[Effects of mitophagy on aerobic exercise intervention for depression in rats].

Objective: This experiment was designed to observe the effects of aerobic exercise on depressive behavior in rats induced by chronic unpredictable mild stress (CUMS), and to explore the possible mechanism by detecting the proteins related to mitochondrial autophagy. Methods: SD rats were randomly divided into three groups: blank control group (C, n=12), depression model group (D, n=12) and post-depression exercise group (D+E, n=12). Group D and D+E were modeled with CUMS for 28 days, and group D+E underwent aerobic exercise intervention for 4 weeks after model establishment. Then the behavior of rats was evaluated. The concentrations of whole brain dopamine and norepinephrine were determined by ELISA kits. The morphology and structure of mitochondria in the frontal lobe were observed with the transmission electron microscope (TEM). Mitochondrial autophagy lysosomes were localized by immunofluorescence colocalization. The expressions of LC3 and P62 proteins in the frontal lobe were measured with Western Blotting. The relative content of mitochondrial DNA was detected using Real-time PCR. Results: ①Compared with group C, the sucrose preference ratio in group D was decreased significantly(P＜0.01); Compared with group D, the sucrose preference ratio in group D+E was increased significantly (P＜0.01). ②In the open field experiment, compared with group C, group D had a significant decrease in activity, average speed and total distance (P＜0.05); Compared with group D, the average rate of activity in group D+E was significantly higher (P＜0.05). ③ELISA results showed that the levels of whole brain dopamine and norepinephrine were significantly lower in group D rats than those in group C (P＜0.05). ④Under transmission electron microscopy, compared with group C, group D had different degrees of mitochondrial swelling, decreased crest density, and intermembrane space dilation.; Compared with group D, a significant increase in mitochondrial autophagosomes and autophagic lysosomes was observed in neurons in group D+E. Increased co-localization of mitochondria with lysosomes in the D+E group could be observed under fluorescence microscopy. ⑤Compared with group C, the expression of P62 was increased significantly(P＜0.05), and LC3II/LC3I ratio was decreased significantly (P＜0.05) in group D; Compared with group D, LC3II/LC3I ratio was significantly higher in group D+E than that in group D (P＜0.05). ⑥Compared with group C, the relative number of mitochondrial DNA in the frontal lobe of group D was increased significantly (P＜0.05). Conclusion: Aerobic exercise has a significant improvement effect on depression induced by CUMS in rats, and its mechanism may be related to the upregulation of the level of linear autophagy.目的: 观察有氧运动对慢性轻度不可预测应激(CUMS)所致的大鼠抑郁行为的影响,并通过检测线粒体自噬的相关蛋白探讨其可能机制。方法: 将SD大鼠随机分为3组:对照组(C)、抑郁模型组(D)和抑郁造模运动组(D+E),每组12只。D组和D+E组进行28 d的CUMS造模,D+E组在造模结束后进行4周有氧运动干预。随后对大鼠进行行为学评估;ELISA测定全脑多巴胺、去甲肾上腺素的浓度;透射电镜(TEM)观察额叶线粒体形态和结构;免疫荧光共定位线粒体自噬溶酶体;Western blot测定额叶中LC3、P62蛋白表达量;Real-time PCR检测线粒体DNA相对含量。结果: ①与C组相比,D组蔗糖偏好比值显著降低(P＜0.01);与D组相比,D+E组蔗糖偏好比值显著增高(P＜0.01)。②旷场实验中,与C组相比,D组的活跃度、平均速度和总路程显著下降(P＜0.05);与D组相比,D+E组活动平均速度显著增高(P＜0.05)。③ELISA结果显示:相比C组,D组大鼠全脑多巴胺和去甲肾上腺素的含量均显著降低(P＜0.05)。④透射电镜显示:与C组相比,D组有不同程度的线粒体肿胀、嵴密度降低、膜间隙扩张等现象;与D组相比,D+E组神经元中可见明显增多的线粒体自噬体和自噬溶酶体。荧光显微镜可观察到D+E组增多的线粒体与溶酶体共定位。⑤与C组相比,D组的P62表达量显著增加(P＜0.05),LC3II/LC3I比值显著降低(P＜0.05);与D组相比,D+E组LC3II/LC3I比值显著升高(P＜0.05)。⑥与C组相比,D组额叶线粒体DNA相对数量显著增多(P＜0.05)。结论: 有氧运动对大鼠CUMS诱发的抑郁有明显的改善作用,其机制可能与上调线线体自噬水平有关。.