Objective: To study the protective effects of triptolide (Tri) on the lipopolysaccharide (LPS)-mediated degeneration of dopaminergic neurons in substantia nigra.
Methods: Forty SD rats were randomly divided into four groups: the sham group, the LPS model group, the Tri group and the normal saline group, 10 in each group. Fourteen days later, the apomorphine-induced rotational behavior, the content of dopamine (DA) and its metabolites in the striatum of the injured side, the number of tyrosine-hydroxylase (TH) positive neurons and activation of microglia in rats were observed.
Results: Injection of LPS in substantia nigra could induce cerebral simulated immunoinflammatory reaction, leading to degeneration of dopaminergic neuron and induce ipsilateral directed rotational behavior of rats, which could be improved by Tri. Moreover, Tri could raise the lowered content of DA and its metabolites as well as the TH positive neurons in striatum, and suppress the activation of microglia significantly (P<0.01).
Conclusion: Tri could protect the dopaminergic neurons from degeneration due to the inflammation mediated by LPS through inhibiting the activation of microglia.