Abstract:Objective To observe the effects of chronic heterotypic intermittent stress ( HIS ) on the gastrointestinal immune system, particularly in terms of (1) the morphology of the gastric and colonic mucosa, and (2) intestinal microbial diversity. Methods We randomly divided 24 SD rats into a control group and a model group. The rats in the model group received HIS for 9 days. After the 9 days of modeling, five rats in the control and model group were randomly selected, and fecal samples were collected for gut microbial diversity analysis. Four of the 12 rats from each of the two groups were randomly selected for perfusion and fixation, and tissues from the gastric antrum and colon were taken for morphological observation. Plasma and adrenal tissues were taken from the remaining eight rats for assessment of corticosterone content. Results (1) After 9 days of HIS, the rats in the model group had gained significantly less weight than those in the control group (P= 0. 001). Furthermore, the corticosterone content in adrenal tissue was significantly lower in the model group vs. the control group (P= 0. 006), and the corticosterone content in plasma was higher in the model group vs. the control group (P= 0. 025). (2) After HIS, the arrangement of gastric mucosal epithelial cells in the model group was thinner than that in the control group (P= 0. 034). Additionally, the number of neutrophils in the lamina propria of the gastric mucosa in the model group was lower than that in the control group (P= 0. 016). The number of neutrophils in the colonic mucosa in the model group was higher than that in the control group (P= 0. 013). (3) After 9 days of HIS, Alpha diversity analysis showed that the number of operational taxonomic units in the fecal samples from the model group was significantly higher than that in the control group (P= 0. 001). The proportion of desulfovibrionaceae and helicobacteraceae in the model group was higher than that in the control group (P= 0. 011, P= 0. 047). Furthermore, the proportion of bacteroidaceae in the model group was significantly lower than that in the control group ( P= 0. 001). Conclusions Nine days of HIS induced a stable rat model of chronic stress in which chronic stress-induced immunosuppression occurred concomitantly with dysregulation of the gut microbial flora.

Abstract:Objective To examine the expression level and distribution of TRIM26 in multiple human and mouse tissues and organs. Methods The immunohistochemistry ( IHC) PV- 9000 two-step method ( non-biotin) was used to determine the expression and distribution of TRIM26. BioGPS was used to calculate TRIM26 expression levels in human tissues and organs, whereas RT-qPCR was performed to determine its counterparts in mice. Results The IHC result indicated that the TRIM26 protein is expressed in the cytoplasm and nucleus, mainly in epithelial cells. Its expression distribution in human esophageal squamous cells, gastric epithelial cells, small intestinal epithelial cells, colon epithelial cells, islet cells, brain glial cells, renal tubular epithelial cells, glomerular cells, and endometrial glandular epithelial cells was consistent with that in the mouse equivalent cells. The highest relative expression of TRIM26 was observed in human tracheal cells and mouse spleen. Conclusions Humans and mice show consistent expression distribution of TRIM26 in multiple tissues and organs, but with different expression levels. Revealing the TRIM26 expression profile in human and mouse main organs and tissues lays a foundation for further exploration of the functions of TRIM26 in different tissues and organs by engineering conditional TRIM26-knockout mice.

Abstract:Objective To assess the effects of P21 inhibitor UC2288 on proliferation and apoptosis of nasopharyngeal carcinoma radioresistant cell line CNE-2R and the possible mechanisms. Methods The effect of UC2288 on cell viability was examined by a CCK-8 assay. The colony formation ability was investigated by a colony formation assay. Changes of cell morphology were observed by microscopy and Hoechst 33342 staining. An annexin V-APC/ 7-AAD assay was used to measure apoptosis. The protein levels of Bax, Cleaved-caspase 3, Caspase 3, Bcl-2, Survivin, γ-H2AX, P21, and PARP were measured by Western blot. Results The CCK-8 assay showed that UC2288 significantly reduced the viability and proliferation of CNE-2R cells in dose- and time-dependent manners. UC2288 also inhibited the colony formation of CNE-2R cells. Cells became round and atrophic, the nucleus shrunk, and the cell volume became smaller after treatment with UC2288. Annexin V-APC/ 7-AAD assays demonstrated that UC2288 induced apoptosis of CNE-2R cells in a dose-dependent manner. After treatment with UC2288, the expression levels of Bax, Cleaved-caspase 3, Caspase 3, and γ- H2AX increased accompanied by decreases of Bcl-2, Survivin, P21, and PARP. Conclusions UC2288 significantly inhibits the proliferation of CNE-2R cells, causes DNA damage, and induces apoptosis through possibly reducing the expression of PARP.

Abstract:Objective To investigate whether there are gender differences in cardiac remodeling induced by chronic sympathetic activation. Methods Mice were randomly divided into four groups: male control, male isoprenaline (ISO), female control, and female ISO groups. A cardiac remodeling model was established by subcutaneous injection of ISO for 14 days. The ratio of heart weight to body weight (HW/ BW) and the ratio of heart weight to tibia length (HW/ TL) were used to assess cardiac remodeling; Cardiac function was assessed using echocardiography to determine diastolic left ventricular posterior wall thickness ( LVPW;d). Hematoxylin and eosin staining was used to determine myocyte cross- sectional area. Picric-sirius red staining was used to evaluate cardiac fibrosis. Results Compared with the control group, the HW/ BW and HW/ TL ratios were increased by 9. 1% (P<0. 05) and 42. 8% (P<0. 001), respectively, in the male ISO group and by 12. 9% and 9. 5% (all P<0. 05), respectively, in the female ISO group. The increase was significantly greater in the male ISO group (19. 8%, P< 0. 01) than in the female ISO group. Compared with the control group, the myocyte cross-sectional area in the male ISO group increased by 19. 1% (P<0. 0001), while that in the female ISO group increased by 6. 9% (P< 0. 05). The increase was significantly greater in the male ISO group ( P< 11. 6%) than in the female ISO group. There was no significant difference in cardiac function among groups. Compared with the control group, the cardiac fibrosis area of the male ISO group increased by 158% (P<0. 0001) and by 39. 7% (P<0. 05) in the female ISO group. Compared with the female ISO group, the fibrosis area of the male ISO group increased by 119% (P<0. 0001). Conclusions There are gender differences in cardiac remodeling induced by chronic sympathetic activation. Greater cardiac hypertrophy and cardiac fibrosis occur in male mice compared with female mice.

Abstract:Objective To examine the effect of modified ectopic pregnancy formula II on levels of apoptosis- related proteins Caspase-7, Caspase-9, and Caspase-3 in the endoplasmic reticulum stress Caspase-12 signaling pathway in human trophoblasts, as well as associated changes in cell ultrastructure, to explore its treatment mechanism for ectopic pregnancy. Methods SD rats were divided into a negative control group ( group B), low-, medium-, and high-dose Chinese medicine groups ( groups C, D, E), a methotrexate group ( group F), and a combined Chinese and Western medicine group ( group G). After receiving the corresponding drug treatment, we collected blood to prepare a drug- containing serum. The drug-containing serum from each group was applied to HTR-8/ SVneo for 24 h, and cells not treated with drug-containing serum were set as a blank control group (group A). The expression levels of apoptotic genes Caspase- 7, Caspase-9, Caspase-3 protein and mRNA in HTR-8/ SVneo cells were detected via Western blot and real-time quantitative PCR. Transmission electron microscopy was used to observe changes in cell ultrastructure. Results (1) There was no difference between group A and group B in terms of Caspase-7, Caspase-9, or Caspase-3 protein levels and relative mRNA expression (P> 0. 05). Compared with group B, expression levels of Caspase-7 mRNA, Caspase-9 protein, and Caspase-3 protein and mRNA were significantly up-regulated in group C ( P < 0. 05), but we found no differences in Caspase-7 protein or Caspase-9 mRNA expression (P> 0. 05). In terms of Caspase-7, Caspase-9, and Caspase-3 protein and mRNA expression, expression was significantly increased in groups D, E, F, and G compared with group B (P < 0. 05), and expression in Group E was significantly up-regulated compared with group D ( P < 0. 05). Group E was compared with group F, expression levels of Caspase-7, Caspase-9 protein and mRNA, and Caspase-3 protein were significantly up-regulated (P < 0. 05). Group E was compared with group G, expression of Caspase-9 protein and mRNA and Caspase-3 protein was significantly increased (P <0. 05). There was no difference between group F and group G (P> 0. 05). ( 2) Transmission electron microscopy indicated that the cell chromatin in group A and group B was evenly distributed in the nuclear membrane, and the endoplasmic reticulum, mitochondria, and Golgi apparatus were clearly visible. Compared with group B, the cell microvilli in groups C, D, E, F, and G were reduced, chromatin was condensed, heterochromatin was marginalized, some mitochondria were swollen, disordered, broken, or even absent, and mitochondrial vacuolation were typical apoptotic characteristics. Conclusions Modified ectopic pregnancy formula II may activate the Caspase-12 signaling pathway of endoplasmic reticulum stress, destroy the morphological structure of trophoblasts, up-regulate the expression of Caspase-7, Caspase-9, and Caspase-3 apoptosis-related genes, and promote trophoblast apoptosis.

Abstract:Objective To develop a method of paraffin-embedded section preparation of whole zebrafish larva. Methods At 4 days post-fertilization, zebrafish larvae were used to explore the effect of two kinds of fixative solution and dehydration reagent on paraffin-embedded sections. Results Overnight 4% PFA fixation was not suitable for brain or muscle tissues of zebrafish larva. The tissue was severely brittle, but it had little effect on the intestines. Bouin’ s fixative solution was suitable for fixation of zebrafish larva, and subsequent use of tert-butanol or ethanol showed little difference. The dehydration by tert-butanol was slightly better than that of ethanol. For Bouin’ s solution-fixed zebrafish larva, brain tissue dehydrated for 1 minute and muscle tissue dehydrated for 4 minutes can obtain a standard paraffin section which has no folds, no cracks and clearly dyed. Conclusions Under optimized conditions, the prepared sections met the standard for paraffin-embedded sections: a complete, uniform thickness, no folds, no knife marks or cracks, a clearly dyed nucleus, moderately red and blue, transparent, and clean. This method can be used as a reference for researchers who need to prepare paraffin-embedded sections of zebrafish larva.

Abstract:Objective To study the pathological changes and virus content of commonly used mice artificially infected with murine norovirus ( MNV). Methods Five strains of common experimental mice ( KM, BALB/ c, NIH, C57BL/ 6 and BALB/ c-nu) were used. Each strain was divided into a control group and an infection group. The infection group was administered MNV solution by gavage and the control group was given saline. Liver, spleen, lung, cecum, colon, and small intestine tissues were collected on days 7, 14, 21, 28, and 55 after infection. Two samples were taken from each tissue; one was for pathological diagnosis and the other was tested for viral nucleic acid content. Results No lesions were found in the cecum, colon, and small intestine. The total incidence of liver, spleen, and lung pathological changes was 8% (10 / 125), 5. 6% (7 / 125) and 4% (5 / 125), respectively. Pathological changes were found in the liver, spleen and lung of KM and BALB/ c mice, the liver and lung of C57BL/ 6 mice, and the liver and spleen of NIH and BALB / c-nu mice. Among them, KM mice were more likely to develop lung lesion. Pathological changes occurred earlier in KM and NIH mice than in C57BL/ 6 mice. MNV nucleic acid positive rates in the cecum and colon were 100% ( 125 / 125), and the positive rates in the small intestine, liver, spleen, lung, and blood were 71. 2% (89 / 125), 17. 6% (22 / 125), 39. 2% (49 / 125), 3. 2% (4 / 125), and 1. 6% (2 / 125), respectively. Comparison of virus contents showed the following order: cecum> colon> small intestine> spleen> lung> liver. BALB/ c-nu mice had significantly higher colon virus contents than the other strains (P < 0. 01), and there was no statistical difference among the remaining tissues of each strain. The cecum and colon virus contents in C57BL/ 6 mice peaked on day 14 after MNV infection (P< 0. 05), but there was no statistical difference in virus contents at other time points in the other strains. There was no correlation between tissue and organ pathological examination and viral nucleic acid test result . Conclusions MNV infection in mice can cause pathological changes in tissues of commonly used experimental mice. It is recommended that MNV-negative mice be selected for pathologically related animal experiments.

Abstract:Objective To study autophagy as the protective mechanism of Zhenwu decotion in cardiomyocytes of rats with heart-yang deficiency. Methods After removal of the thyroid and intraperitoneal injection of doxorubicin, to establish the rat heart and kidney yang deficiency model, rats were administered with corresponding drugs for 10 days. We measured serum triiodothyronine (T₃), thyroxine (T₄), thyroid-stimulating hormone (TSH), and myocardial tissue BNP, LA, and CaN by ELISAs. LC3, ATG5, and P62 and protein expression was detected by western-blot. Inspected LC3 and P62 expression in rat myocardial tissue was examined by immunohistochemistry. ThePathological changes of myocardial tissue were observed by HE staining. Results Zhenwu decotion reduced the BNP content in myocardial tissue of rats with heart-yang deficiency-induced heart failure, increased the LA content in myocardial tissue, decreased the CaN content, increased LC3, ATG5, and BECLIN1 contents, and decreased the P62 content in myocardial tissue of rats with heart failure. Conclusions Zhenwu decotion improves the heart failure condition and energy metabolism of the heart. In the early stage of heart failure, the damaged cardiomyocytes protected by regulating autophagy.

Abstract:Objective To establish a stable Parkinson’s model in C57BL/ 6 mice by MPTP and assess behavioral scores of the model. Methods Dosing groups (35, 30, and 25 mg / kg body weight MPTP) and control group (30 mg / kg body weight physiological saline) were established. We conducted the paralysis agitans score, open field test, pole test, traction test, swim test, and comprehensive statistical analysis. We then analyzed the differences between each group and the control group. HE staining and TH immunohistochemical staining were performed to observe the substantia nigra, striatum neurons, and nerve fibers. Results Compared with the control group, the scores of drug administration groups were significantly higher. The ethology score of the 25 mg / kg dose group was significantly lower than those of 35 and 30 mg / kg groups. No significant difference was found between 35 mg / kg and 30 mg / kg groups. Substantia nigra TH-positive neurons and striatum TH-positive nerve fibers were decreased. Conclusions A simple method was established to evaluate a Parkinson’s disease model in mice by behavioral data.

Abstract:Objective To compare learning-memory ability in C57BL/ 6J, BALB/ c, and ICR mice. Methods Adult male mice were divided into three groups with 10 C57BL/ 6J, BALB/ c, or ICR mice in each. The learning-memory ability of the three mice strains was evaluated via the open-field test, Barnes maze test, Y-maze test, and fear-conditioning test. Results In the open-field test, the total distance, largest distance, velocity, center distance / total distance, and the center time were significantly lower in the C57BL/ 6J group compared with the BALB/ c and ICR groups (P< 0. 01, P<0.05). The small distance in the C57BL/ 6J group was significantly greater than that in the BALB/ c and ICR groups (P< 0. 01, P< 0. 05). In the Barnes maze test, the latency to reach the entry zone was significantly lower in the C57BL/ 6J group compared with the BALB/ c and ICR groups in the learning stage on the second and fourth days ( P< 0. 05, P< 0. 05). In the test phase, the time spent in the entry zone in the C57BL/ 6J and ICR groups was significantly greater than that in the BALB/ c group (P< 0. 01, P< 0. 05). In the Y maze test, we found no significant differences in spontaneous alternations, time spent in each arm, and number of arm visits among the three groups. In the fear-conditioning test, the percentage of freezing time among the three groups was not significantly different. Conclusions In the open-field test, C57BL/ 6J mice exhibited the lowest spontaneous activity level and the highest anxiety level. In the maze test, spatial reference memory in C57BL/ 6J mice was superior to that of BALB/ c and ICR mice. There were no statistically significant differences in spatial working memory or spatial recognition memory among the 3 strains.

Abstract:Objective To analyze the use of animal models of chloasma, and to lay a good foundation for future animal studies designed to explore the basic biology of chloasma, test new therapies, and develop new drugs, so as to generate scientific, rigorous, and safe treatment approach for chloasma. Methods The CNKI, Wanfang and Weipu databases were searched for all publication pertaining to the key word “chloasma”, with the following time ranges: 1960 – 2019, 1990 – 2019, and 1979 – 2019. The application of animal models in the literature and the detection of relevant indicators were analyzed and summarized. Results A total of 104 experimental studies were retrieved. Female KunMing (KM)mouse models of chloasma were the most common, and UV irradiation was the most common method used to induce chloasma. The most common experimental duration was 30 days, and all of the studies lasted for at least 7 days. Drugs were typically administered for between 28 and 31 days. The indicators that were assessed can be divided into apparent indicators, biochemical indicators, and pathological indicators. Assessment of biochemical indicators was most common, primarily focusing on changes in oxidation-related factors in the skin and serum. Conclusions There is a serious imbalance between experimental research and theoretical discussions related to chloasma and the clinical need for chloasma treatments. The establishment of a compound animal model and an animal model with TCM disease characteristics will be an important focus for future research. Existing studies of the mechanisms of drug activity are limited to imbalances in the body, surface oxidation, and anti-oxidation, and ignore factors related to endocrine disorders. In-depth studies of body surface NEI networks to identify factors that can alter body properties may be an important research direction for developing new treatments for chloasma, whether they exhibit full or partial effectiveness.

Abstract:Objective We investigated the role of miR-181b in regulating atherosclerotic plaque formation in atherosclerosis (AS) by targeting Mex3B expression. Methods Male Sprague-Dawley rats were randomly divided into a normal group, model group, control group, and experimental group. A mixture of miR-181b-inhibitor-NC and miR-181b- inhibitor was injected into the control group and the experimental group, while rats in the normal group and model group received the same amount of saline. At 24 hours after the injection, a 600, 000 U/ kg dose of vitamin D3 was intraperitoneally injected into the rats in the model group, control group, and experimental group, which then received a daily 100 g high-fat diet. The rats in the normal group always received the same amount of a basic diet. After 60 days of feeding, the rats underwent carotid ultrasound examination to measure the intima-media thickness of the posterior wall of the artery (IMT) and the plaque area (square, S). RT-PCR was used to detect miR-181b expression and the mRNA of Mex3B protein, and a Western blot was used to detect the expression of Mex3B protein. A luciferase reporter gene analysis was used to examine the regulatory relationship between miR-181b and Mex3B. Results Compared with the normal group, carotid intima hyperplasia was evident in the model group, and we observed significant increases in carotid IMT, plaque S, miR-181b and Mex3B mRNA expression, and Mex3B protein expression (P< 0. 05). Compared with the model group, carotid intima hyperplasia was evident in the experimental group, and we observed significant decreases in carotid IMT, plaque S, miR-181b and Mex3B mRNA expression, and Mex3B protein expression (P< 0. 05). Luciferase reporter gene analysis demonstrated that miR-181b targets Mex3B. Conclusions miR-181b is involved in the inflammatory stress response in atherosclerosis by targeting Mex3B expression. Inhibition of miR-181b expression may significantly inhibit inflammatory responses and reduce plaque formation in AS.

Abstract:Objective To evaluate the mechanism of ceramide in aged platelets mediated by transfusion-related acute lung injury (TRALI). Methods The second hit model of TRALI was established in mice via lipopolysaccharide prestimulation, and platelets were transfused and stored for 1-5 days. ARC39 (a specific acid sphingomyelinase inhibitor) or platelets from acid sphingomyelinase-deficient mice were used to treat BALB/ c mice. Temporal changes in platelet sphingomyelin composition were analyzed. We examined the accumulation of neutrophils in the lungs of TRALI mice, as well as the function of the endothelial barrier and the histology of injured lung tissue. Results Platelets were collected and stored for 1~ 5 days from mice prestimulated by LPS, which caused characteristic lung injury, and the severity of lung injury increased with time. Ceramide in platelets accumulated and decreased during storage. Compared with the control group, transfusion of ARC39 preconditioned platelets or acid sphingomyelinase deficient platelets significantly alleviated lung injury. Conclusions Aging platelets can lead to TRALI in mice, but this damage can be reversed and treated by an acid sphingomyelinase inhibitor or specific knockout of the acid sphingomyelinase gene. Such intervention measures for sphingolipid formation are expected to be an effective strategy for increasing the storage safety and shelf life of blood products.

Abstract:Objective To explore the relationship between expression of brain derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the hippocampus and forebrain cortex and depression induced by chronic stress in mice. Methods We randomly divided 58 SPF KM mice (29 male, 29 female) into a control group and observation group. We induced stress in the mice in the observation group via fasting, electric shock, and other techniques. The mice in the control group were not exposed to experimental stressors. We weighed the mice before stress induction, 10 days after, and 20 days after stress induction. We then observed and recorded the result of the Morris water maze test and open field test in both groups. We measured BDNF and VEGF expression in the hippocampus and forebrain cortex in each group, and analyzed the correlation. Results Before stress induction, there were no significant differences between the two groups (P> 0. 05). After stress induction, the mice in the observation group weighed significantly less than those in the control group ( P< 0. 01). The escape latency, swimming distance, and time spent in the second quadrant were significantly higher in the observation group vs. the control group (P< 0. 05 or P< 0. 01), but there were no significant differences in the time spent in the other quadrants ( P> 0. 05). The modification times and vertical movement scores of the mice in the observation group were significantly lower than those in the control group, and the retention time in the central area was significantly higher than that in the control group ( P< 0. 01). There was no significant difference in the number of defecation particles (P> 0. 05). The BDNF and VEGF expression levels in the CA1 area of the hippocampus and forebrain cortex were lower in the observation group vs. control group, but this difference was not significant (P> 0. 05). Conclusions Chronic stress can induce depressive behavior in mice, which may be related to decreased BDNF and VEGF expression in the hippocampus and forebrain cortex.

Abstract:Online teaching of laboratory animal science during the COVID-19 epidemic situation is an effective supplement and improvement to the traditional teaching model. It is necessary to know the operation of network software packages and apply them to realize the transformation of teaching consciousness. Teachers should maintain continuity of teaching ideas, focusing on the presentation of PPT, and demonstrate animal experimental operations using the existing Massive Open Online Course (MOOC) resources. All efforts are to teach students how to effectively master the content of lectures in the network environment. Moreover, the content related to COVID - 19, especially for animal experiments, should be included in lectures to stimulate the students’ interest in learning. We should also improve course evaluation method , promote the reform of laboratory animal science teaching, and constantly enrich the teaching model of laboratory animal science.

Abstract:Cardiac hypertrophy is a slow and effective compensatory function that mainly occurs under long-term stress loads. It is an adaptive response to changes in hemodynamics or myocardial injury. Decompensation of myocardial hypertrophy can eventually lead to an increased incidence of heart failure and sudden death, and no effective treatments have been established. In this paper, we summarize and compare the preparation method and characteristics of animal models of cardiac hypertrophy, including mice, rats, and large animals. We also summarize and compare the classical molecular signaling mechanisms of cardiac hypertrophy, including the mitotic protein kinase signaling pathway and the Ca²⁺ mediated signaling pathway, as well as the molecular mechanisms of decompensation induced by cardiac hypertrophy, including catecholamine and the cardiomyocyte apoptosis signaling pathway.

Abstract:Danio rerio has many advantages as a model animal for nanotoxicology research, such as small size, easy propagation, high reproduction rate, short reproduction cycle, amenable to in vitro fertilization, transparent embryo and easy observation. We review the toxic effects of nanomaterials on Danio rerio, including digestive toxicity, reproductive toxicity, neurological toxicity and embryonic toxicity. The mechanisms of toxicity include oxidative stress, apoptosis, and perturbed gene expression and cell cycle. The main factors influencing the toxicity of nanomaterials are analyzed, including chemical composition, concentration or dose, particle size, shape, drug administration and material preparation method . This review provides a reference for the use of zebrafish as a model for nanotoxicology research.

Abstract:“One Health” is a health concept that aims to achieve common health for people, animals and the environment through the joint efforts of multiple disciplines at local, national and global levels. Its embryonic form first appeared in 18th century European comparative medicine. It has gradually matured in the 21st century after more than 100 years of development. Under the guidance of this concept, many countries and regions have adjusted the use of antibiotic- containing animal growth promoters and zoonotic disease prevention programs to varying degrees. This has achieved many positive result , showing that "One Health" has a positive impact on national health. In addition, because of the special nature of laboratory organisms, improper use may lead to biological accidents that could pose a huge threat to public health. Therefore, the elimination of safety hazards concerning laboratory organisms is an important part of achieving universal health. This article summarizes the development of " One Health " with respect to public health issues and safety management of laboratory organisms and discusses connotations of its application.

Abstract:Mice are a small mammal model for scientific research. Before studying non-human primates and human embryos, it must be determined whether the experiment can be carried out in mice and then employ higher mammals. The limitation of the existing system is that mouse embryos can only be cultured in vitro to E6. 5. Establishment of a mouse embryo in vitro culture system is very important to understand the critical events and molecular mechanisms of embryo peri- implantation. The development of single-cell RNA sequencing technology provides new possibilities for in vitro time-lapse culture of mouse embryos. Here, we introduce an in vitro time-lapse culture system and 3D culture system for mouse embryo implantation, the application of single-cell RNA sequencing technology in the field of embryos, and its possible future direction of development.

Abstract:Mesenchymal stem cells (MSCs) are a type of adult stem cell that originates in the early mesoderm, which are capable of self-renewal and multi-directional differentiation. A large number of studies have shown that MSCs have great potential in the field of regenerative medicine. MSCs can be used to treat many types of diseases such as spinal cord injury, liver damage, kidney damage and autoimmune diseases. They are generally derived from placenta, fat, dental pulp, bone marrow, umbilical cord, and fetal internal organs as well as other organs and tissues. Among them, the umbilical cord as a link between the mother and fetus to transport nutrients contains a large number of MSCs. Compared with bone marrow mesenchymal stem cells that are affected by the donor’s age and fetal mesenchymal stem cells that have ethical issues, umbilical cord mesenchymal stem cells ( hUCMSCs) have a high proliferation efficiency and wide range of donor sources, and low virus infection rate. Therefore, hUCMSCs are considered to be a better choice for treatment of virous diseases. These advantages also make hUCMSCs attractive in the field of regenerative medicine. This article focuses on the current research progress of hUCMSCs related to disease treatment.