Gastrodin inhibits neuroinflammation in rotenone-induced Parkinson's disease model rats★

The present study showed that the latency of rats moving on a vertical grid was significantly prolonged, and the number of rats sliding down from the declined plane was increased remarkably, in rotenone-induced Parkinson's disease model rats compared with control rats. The moving latency recovered to normal levels, but the number of slides was significantly increased at 28 days after model establishment. The slope test is a meaningful approach to evaluate the symptoms of Parkinson's disease model rats treated with rotenone. In addition, loss of substantia nigral dopaminergic neurons in model rats was observed at 1 day after the model was established, and continued gradually at 14 and 28 days. The expression of tyrosine hydroxylase-positive cells was significantly increased in gastrodin-treated rats at 14 days. Significant numbers of activated microglia cells were observed in model rats at 14 and 28 days; treatment of rats with Madopar at 28 days suppressed microglial activation. Treatment of rats with gastrodin or Madopar at 28 days significantly reduced interleukin-1β expression. The loss of substantia nigral dopaminergic neurons paralleled the microglial activation in Parkinson's disease model rats treated with rotenone. The inflammatory factors tumor necrosis factor-α and interleukin-1β are involved in the substantia nigral damage. Gastrodin could protect dopaminergic neurons via inhibition of interleukin-1β expression and neuroinflammation in the substantia nigra.