ABSTRACT
OBJECTIVE@#To investigate the activation characteristics of microglia (MG) in the rats striatum with MA-induced neurotoxicity.@*METHODS@#Male Wistar rats were divided randomly into control group (n=24) and experimental group (n=24). The rats of experimental group were injected intraperitoneally with MA (15 mg/kg x 8 injections, at 12 hours interval). The rats of control group were administrated with saline. The tissues of striatum of two rat groups were harvested at 0.5 d, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d and 7 d post initial administrations of MA or saline. The structure changes were observed by transmission electron microscopy and CD-11b immunohistochemistry. The ratio of activated MG was calculated and statistically analyzed.@*RESULTS@#In the control group, the morphological characteristics of the MG showed that the cell bodies were small with slender processes, high electronic density nucleus, and fewer organelles known as the "fork-type". In contrast, the MG in the MA-induced neurotoxicity group displayed larger cell body, shorter cell processes or disappeared, lower electronic density nucleus and rich organelles, resembling "bush-like" or "amoeba-like". The ratio of activated MG in control group was below 0.15 at all timepoints, whereas in the experimental group, the ratio of activated MG increased significantly from day 1 to day 7 (P<0.001).@*CONCLUSION@#The continuous MA stimulation of the CNS results in prominent MG activation.