有氧运动对去卵巢应激大鼠学习记忆行为及海马内质网应激介导的细胞自噬及凋亡的影响

Effects of Treadmill Exercise on Learning Memory Behaviour and Hippocampal Autophagy-Induced Apoptosis in Ovariectomized Stressed Rats

目的:通过检测海马内质网应激相关蛋白PERK、elf2α、CHOP和自噬标志物LC-3Ⅱ/Beclin-1及凋亡因子Caspase-3的表达,探讨为期4周的中等强度跑台训练对去卵巢结合慢性应激大鼠学习记忆能力改善的可能机制。方法:40只SD大鼠随机分为对照组(sham,n=10)、卵巢切除组(OVX,n=10)、卵巢切除应激组(OVX+S,n=10)和卵巢切除应激运动组(OVX+S+E,n=10)。除假手术对照组大鼠外,其余3组大鼠摘除卵巢建立围绝经期大鼠模型,再运用慢性不可预测性应激(chronic unpredictable stress,CUMS)构建抑郁大鼠模型。同时,运动组的去卵巢应激大鼠接受4周中等强度跑台运动。在运动及应激结束后采用八臂迷宫实验测试大鼠学习记忆行为。Western blot检测海马PERK/elf2α/CHOP、海马凋亡因子Caspase-3蛋白水平及自噬标志物LC-3Ⅱ/Beclin-1蛋白表达。结果:(1)去卵巢使大鼠学习记忆能力下降,行为学表现为在八臂迷宫实验中大鼠工作记忆错误次数、参考记忆错误次数和完成时间均显著增加。结合慢性不可预测性应激后,上述测量指标增加更为明显,去卵巢(OVX)及去卵巢应激(OVX+S)组大鼠海马凋亡因子Caspase 3蛋白表达显著升高,内质网应激相关蛋白PERK、elf2α、CHOP表达水平增加,自噬相关蛋白Beclin 1和LC3Ⅱ蛋白表达也显著降低。OVX+S组更为显著。(2)4周中等强度跑台运动可显著增强大鼠学习记忆能力。与去卵巢应激组相比,去卵巢应激运动组大鼠细胞凋亡因子Caspase 3蛋白表达下降,内质网应激相关蛋白PERK、elf2α、CHOP表达降低,自噬标志物Beclin 1和LC3Ⅱ蛋白表达显著升高。结论:跑台运动可增强去卵巢抑郁模型大鼠的学习记忆能力,其作用机制可能与长期跑台运动通过促进细胞自噬抑制内质网应激PERK/elf2α/CHOP信号通路,降低细胞凋亡有关。

This paper aims to investigate the possible mechanism of the improvement of learning memory ability in ovariectomized stressed rats by 4 weeks of moderate-intensity trendmill exercise by detecting the expression of hippocampal autophagy-related proteins PERK,elf2α,CHOP and autophagy markers LC-3II/Beclin-1 and apoptosis factor Caspase-3.Forty SD rats were randomly divided into four groups,namely sham operation group(sham group,n=10),ovary removal group(OVX group,n=10),ovary removal stress group(OVX+S group,n=10)and ovary removal stress exercise group(OVX+S+E group,n=10).Except for the sham-operated group of rats,the remaining three groups of rats had their ovaries removed to establish a perimenopausal rat model,and then a depressed rat model was established by chronic unpredictable stress(CUMS),while the rats in the ovariectomized stress exercise group underwent a 4-week moderate-intensity treadmill exercise.The eight-arm maze experiment was used to test the learning and memory behavior of rats after exercise and stress,and Western blot was used to detect the protein levels of PERK/elf2α/CHOP,hippocampus apoptotic factor Caspase-3 and the protein expression of autophagy markers LC-3II/Beclin-1 in the hippocampus.Results show firstly ovary removal reduced the learning memory abacity of rats,as evidenced behaviorally by a significant increase in the number of working memory errors,the number of reference memory errors,and the completion time in the eight-arm maze experiment,and an even more pronounced increase in the above measures when combined with chronic unpredictable stress,the expression of hippocampal apoptotic factor Caspase 3 protein was significantly elevated in the ovary removal(OVX)and ovary removal stress(OVX+S)groups the expression of autophagy-related proteins PERK,elf2α,CHOP was increased,whereas the expression of mTOR protein was elevated,and the expression of Beclin 1 and LC3II proteins was also significantly decreased,which was more significant in the OVX+S group.Secondly,four weeks of moderate-intensity treadmill exercise significantly enhanced the learning memory ability of rats.Compared with the de-ovo stress group,the expression of apoptosis factor Caspase 3 protein decreased,the expression of autophagy-related proteins PERK,elf2α,CHOP was decreased,and the expression of autophagy markers Beclin 1 and LC3II protein was significantly elevated in the ovary remoral stress exercise group.It is concluded that treadmill exercise can enhance the learning memory ability of rats in the ovariectomized depression model,and its mechanism of action may be related to the fact that long-term treadmill exercise promotes cell autophagy and reduces apoptosis by inhibiting the ERS of PERK/elf2α/CHOP signaling pathway.