七氟醚致幼鼠认知功能障碍与Tau/TTLL6/Spastin信号通路的相关机制

The mechanism of cognitive dysfunction induced by sevoflurane and the Tau/tubulin tyrosine like ligase 6/Spastin signaling pathway in young rats

目的探讨多次暴露于吸入性麻醉药七氟醚后, 七氟醚是否通过Tau/类微管蛋白酪氨酸样连接酶6(TTLL6)/微管切割蛋白(Spastin)信号通路引起幼鼠神经元树突棘重塑。方法选取幼年[出生6 d(P6)]及成年[出生60 d(P60)]小鼠44只, 采用随机数字表法将小鼠分为4组(每组11只):幼年对照组(P6con组)、幼年麻醉组(P6sevo组)、成年对照组(P60con组)、成年麻醉组(P60sevo组)。P6sevo组和P60sevo组给予3%七氟醚+60%氧气3 d, 每天2 h;P6con组和P60con组给予60%氧气3 d, 每天2 h。造模结束后当天取小鼠海马组织采用免疫印迹法(Western blot)检测突触后致密蛋白95(PSD95)、Tau、TTLL6、Spastin水平, 免疫荧光检测Tau、TTLL6、Spastin表达及Tau、TTLL6共定位情况。结果与P6con组比较, P6sevo组海马PSD95水平较低(P<0.05), Spastin水平较高(P<0.05), Tau、TTLL6水平差异无统计学意义(均P>0.05);P60con组与P60sevo组海马组织PSD95、Tau、TTLL6、Spastin水平比较, 差异无统计学意义(均P>0.05)。免疫荧光染色结果显示, P6con组和P6sevo组小鼠海马组织Tau和TTLL6存在共定位, P60con组和P60sevo组小鼠海马组织Tau和TTLL6共定位不明显;与P6con组比较, 多次七氟醚处理可使P6sevo组海马中Tau、TTLL6及Spastin阳性细胞明显增加(均P<0.05), 而在成年小鼠中变化不明显(P>0.05)。结论七氟醚通过Tau/TTLL6/Spastin信号通路引起幼鼠神经元树突棘重塑。

Objective To explore whether the inhaled anesthetic sevoflurane after repeated exposure causes dendritic spine remodeling of neuronal neurons in young mice through the Tau/tubulin tyrosine like ligase 6(TTLL6)/microtubule dissecting protein(Spastin)signaling pathway.Methods A total of 44 juvenile[postnatal 6 d(P6)]and adult[postnatal 60 d(P60)]mice were selected.According to the random number table method,the mice were divided into four groups(n=11):a juvenile control group(the P6con group),a juvenile anesthesia group(the P6sevo group),an adult control group(the P60con group)and an adult anesthesia group(the P60sevo group).The P6sevo and P60sevo groups were administered with 3%sevoflurane+60%oxygen for 3 d,2 h/d;while the P6con and P60con groups were given 60%oxygen for 3 d,2 h/d.On the day after molding,mouse hippocampus tissue was collected to detect the levels of postsynaptic dense protein 95(PSD95),Tau,TTLL6 and Spastin by Western blot.The expression of Tau,TTLL6 and Spastin,and the co‑location of Tau and TTLL6 were detected by immunofluorescence.Results Compared with the P6con group,the P6sevo group showed decreases in the levels of hippocampal PSD95(P<0.05),and increases in the levels of Spastin(P<0.05),without statistical difference in Tau and TTLL6 expression(both P>0.05).There was no statistical difference in hippocampal PSD95,Tau,TTLL6 and Spastin levels between the P60con group and the P60sevo group(all P>0.05).The results of immunofluorescence staining showed that Tau and TTLL6 were co‑localized in the P6con group and the P6sevo group,while the co‑localization of Tau and TTLL6 in the hippocampal tissue of the P60con and P60sevo groups was not obvious.Compared with the P6con group,repeated exposure to sevoflurane resulted in remarkable increases in the number of Tau‑,TTLL6‑and Spastin‑positive cells in the hippocampus of the P6sevo group(all P<0.05).The above changes were not significantly in adult mice(P>0.05).Conclusion Sevoflurane causes dendritic spine remodeling in young rat neurons through the Tau/TTLL6/Spastin signaling pathway.