Abstract:Objective To observe the effect of early exercise intervention on motor dysfunction in a Parkinson′s disease (PD) model in rats, and to explore the cumulative effect of early exercise on improving motor dysfunction. Methods Male specific pathogen?free SD rats were randomly divided into four groups: sham?operated quiet (SHAM?S), sham?operated exercise (SHAM?E), PD quiet (PDS), and PD exercise (PDE) groups. A unilateral PD rat model was established by injecting 6?hydroxydopamine (6?OHDA) into the right medial forebrain bundle (MFB) of rats. The exercise group started running on a treadmill at 24 hours after surgery. Rats were assessed for behavioral functions using cylindrical and grid tests every 7 days after modeling. Tyrosine hydroxylase ( TH) content in striatum ( Str) was assessed by immunohistochemistry and western blotting on days 14 and 28 after modeling. Results (1)The number of TH+ cells in Str on the affected side of PD model rats was significantly decreased and then gradually decreased over time. The number of TH+ cells in Str on the affected side of PDE group rats was significantly increased, but there was no significant change over time. (2)The cylinder test score of PD model rats was significantly increased, but there was no significant change over time. In the PDE group, no statistically significant difference was found in test scores on days 1, 4, 7, 11, and 14. However, the scores were significantly decreased on days 21 and 28, indicating significant recovery in left forelimb activity. (3)The number of forelimb drops on the affected side was significantly increased in the PDS group, but did not show any significant change over time. Conversely, the number of forelimb drops on the affected side of PDE group rats was significantly decreased and continued to decrease over time. (4)Additionally, the number of grids and total steps of PDS group rats were significantly decreased at each time point, exhibiting a significant downward trend over time. Conversely, PDE group of rats showed a significant increase starting from day 4 and did not show any significant change over time. Conclusions Unilateral MFB injection of 6?OHDA into rats leads to motor dysfunction. Early exercise intervention effectively improves the motor dysfunction of PD model rats, while also suppressing the decrease in dopamine content in the substantia nigra striatum. Moreover, the effect of exercise intervention increases over time.