Nicotine inhibits the inflammation induced by 6-hydroxydopamine lesion in the striatum of SD rat / 中华老年医学杂志

ABSTRACT

Objective To explore the mechanism through which nicotine protects dopaminergic neurons against 6-OHDA toxicity in SD rat. Methods Rats received nicotine or saline treatment (two doses tested,0. 2 rag/ kg and 2 rag/ kg, 5 injections i.p. per day at 2-h intervals). On day 8after the treatment, a single injection of 20μg of 6-OHDA was administered into right striatum.Nicotine or saline was administered continuously daily until animals were killed. The dopaminergic neurons and CD3, CD4 and CDS-positive lymphocytes were analyzed quantitatively using immunohistochemistry. Microglia activation was quantified by IBA1 immunofluorescence. Results The loss of dopaminergic neurons induced by 6-OHDA in the substantia nigra was significantly less severe in the nicotine treatment group (at both 0. 2 and 2 mg/kg groups) than that in the saline treated group. In the striatum, we observed that the number of CD3, CD4 and CD8-positive lymphocytes reduced significantly in the nicotine treated animals as compared to saline controls. Otherwise, nicotine inhibited CD4 and CD8-positive lymphocytes infiltration equivalently. Quantitative immunofluorescenee analysis indicated the microglia activation was inhibited obviously in nicotine treatment. Conclusions Our data suggest that nicotine may have a neuroprotective effect against dopaminergic lesion induced by 6-OHDA by inhibiting the inflammation.