Experimental Study on the Connection of Nigral Apoptosis of Normal Rats and Rats of Parkinson Disease with Different Doses of Levodopa

Objective: To evaluate the neuronal toxicical effects induced by levodopa and explore the method in which PD can be treated reasonably with levodopa. Method: The rat models of Parkinson disease (PD) were made by injecting stereotaxically 6-OHDA to right side of the mesencephic ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). The PD rats were treated intraperitoneally with different dosages (10 mg/kg/d, 50 mg/kg/d, 100 mg/kg/d) and different durations (1 d, 3 d, 5 d, 7 d) of levodopa. At the same time, we observed the injury of substantia nigral by the way of treating PD rats with levodopa for 7 days and then stopped for 7 days. In this study, we used TUNEL to detect the injury of substantia nigra by different doses and durations of levodopa. Results: The number of substantia nigral apoptosis was increased with the changes of doses and durations of levodopa. Conclusions: If we use levodopa intermittently or as little as possible, the toxical action of levodopa may be reduced.