Objective To investigate the effect of dexmedetomidine on the renal function and the expression of tight junction protein ZO-1 and occluding in the kidney of rats with septicopyemia induced by lipopolysaccharide.Methods Thirty adult male SD rats were randomly divided into 3 groups (n=10 each):control group(group C), LPS group (group M), and dexmedetomidine group (group Dex). In the groups Dex and LPS, the rats were infused with saline and lipopolysaccharide (5 mg/kg, i.v.) respectively. In the Dex group, after intravenous injection of lipopolysaccharide (5 mg/kg), the rats were firstly infused the loaded dose of dexmedetomidine (7 μg/kg) for 15 minutes, and then changed to 5 μg/kg·min for 30 minutes. Blood samples were collected at 24 h later for measuring TNF-α, IL-1β, Scr and BUN. The kidney tissues were examined by histopathology. The expression of ZO-1 and occludin was detected by Western blot. Results Compared with the group C, the kidney tissue of group M was extensively damaged with tubular dilatation and inflammation, while reduced in the group Dex. Compared with the group C, the expressions of Scr, BUN, IL-1β and TNF-α were all enhanced in the groups M and Dex (P<0.05), while the inflammatory factors in the group Dex were significantly lower than those of the group M (P<0.05). The Results The Western blot analysis showed that the expressions of protein ZO-1 and occludin in the group Dex were significantly higher than those of the group M (P<0.05). Conclusions Dexmedetomidine can improve the renal function of rats with septicopyemia, inhibit the acute renal injury and inflammation, increase the expression of protein ZO-1, and exert certain protective effect on the kidneys.