ABSTRACT
Aim To explore the roles of miRNA-132 and its related proteins(Mecp2, CREB)in the mechanism of methamphetamine(MA)-induced neurotoxicity and dependence.Methods The rats were intraperitioneally injected(ip)with MA(10 mg·kg-1·d-1)to establish methamphetamine dependence model with different dependent time courses of 1 week, 2 weeks, and 4 weeks respectively.The miRNA-132 and Mecp2 mRNA were detected by RT-qPCR, and the Mecp2, p-Mecp2, CREB and p-CREB proteins were detected by Western blot in the tissues of frontal cortex and hippocampus.Results In the frontal cortex, the miRNA-132 and Mecp2 mRNA were up-regulated in MA-dependent groups(P<0.05 and P<0.01), while the Mecp2 protein were down-regulated(P<0.01).MA could promote the phosphorylation of Mecp2 protein in the frontal cortex(P<0.01).In hippocampus, the miRNA-132 was down-regulated in the MA-dependent groups, but Mecp2 mRNA was up-regulated(P<0.05).Mecp2 protein increased in MA-dependent 1 week group(P<0.05), and then recovered with the prolonged time of MA dependence, then decreased in MA-dependent 4 weeks groups(P<0.05)in hippocampus.The phosphorylation level of Mecp2 was significantly decreased in the 1 week group(P<0.01), and then increased in the 2 weeks group(P<0.01)in hippocampus.Conclusions MA could induce an abnormal expression of miRNA-132 in the frontal cortex and hippocampus, and miRNA-132 might inhibit the translation of Mecp2 mRNA and induce the decrease expression of Mecp2 protein in the frontal cortex.But in hippocampus, miRNA-132 does not show the correlation with the Mecp2 expression trend of the frontal cortex.And miRNA-132 regulation does not depend on the expression of Mecp2 in hippocampus.
ABSTRACT
Objective To observe the curative mechanism and effect of neurotoxicity injury induced by methamphetamine (MA) and the neuroprotective effects of gastrodin interfered. Whether the expression of astrocyte and proinflammatory cytokines has contributed to the effects of gastrodin.Methods 48 healthy male SD rats were randomly divided into three groups: control group (Daily intraperitoneal injection of saline for 8 weeks),MA group (A dose of 10 mg/kg MA was administered every day for four weeks,then given daily intraperitoneal injection with 10 mg/kg saline for 4 weeks) and gastrodin group (A dose of 10 mg/kg MA was administered every day for four weeks,then given daily intraperitoneal injection with 10 mg/kg gastrodin for 4weeks) . The behavioral changes of rats were measured by conditioned place preference ( CPP) and sterotyped behavior ( SB) induced by methamphetamine. Immunofluorescence staining was used to detect the expression of glial fibrillary acidic protein (GFAP) and NEUN in rat frontal cortex.The expression of IL－6 and TNF－α were detected by quantity RT－PCR and westrn bloting.Results Compa MA depndent 4 weeks group with control group, the scores of sterotyped behavior of MA depndent groups had signficantly increased (P＜0.01) . Comparing MA depndent 4 weeks group with MA depndent 4 weeks+gastrodin group, the scores of sterotyped behavior of MA dependent 4 weeks group had obviously decreaseed (P＜0.01) . Compared with the control group, the expression of GFAP of MA dependent 4 weeks group decreased and the expression of NEUN increased. Compared MA dependent 4 weeks group with control group, the expression of IL－ 6 and TNF－α increased (P＜0.01) . Compared MA dependent 4 weeks+gastrodian group with MA dependent 4 weeks group, the expression of TNF－α and IL－6 significantly reduced (P＜0.01) . Conclusion The neurological damage induced by methamphetamine might be related to the activation of astrocytes and the high expression of inflammatory cytokines including IL－6 and TNF－α. Gastrodin could abate the neurological injury of methamphetamine dependence via reducing the activation of astrocytes and decreasing the expression of IL－6 and TNF－α.