Abstract： Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.