Running exercise has been shown to relieve symptoms of depression, but the mechanisms underlying the antidepressant effects are unclear. Microglia and concomitant dysregulated neuroinflammation play a pivotal role in the pathogenesis of depression. However, the effects of running exercise on hippocampal neuroinflammation and the number and activation of microglia in depression have not been studied. In this study, rats were subjected to chronic unpredictable stress (CUS) for 5 weeks followed by treadmill running for 6 weeks. The depressive-like symptoms of the rats were assessed with a sucrose preference test (SPT). Immunohistochemistry and stereology were performed to quantify the total number of ionized calcium-binding adapter molecule 1 (Iba1)⁺ microglia, and immunofluorescence was used to quantify the density of Iba1⁺/cluster of differentiation 68 (CD68)⁺ in subregions of the hippocampus. The levels of proinflammatory cytokines in the hippocampus were measured by qRT-PCR and ELISA. The results showed that running exercise reversed the decreased sucrose preference of rats with CUS-induced depression. In addition, CUS increased the number of hippocampal microglia and microglial activation in rats, but running exercise attenuated the CUS-induced increases in the number of microglia in the hippocampus and microglial activation in the dentate gyrus (DG) of the hippocampus. Furthermore, CUS significantly increased the hippocampal levels of inflammatory factors, and the increases in inflammatory factors in the hippocampus were suppressed by running exercise. These results suggest that the antidepressant effects of exercise may be mediated by reducing the number of microglia and inhibiting microglial activation and neuroinflammation in the hippocampus.

跑步锻炼已被证明可以缓解抑郁症状，但抗抑郁作用的潜在机制尚不清楚。小胶质细胞和伴随的神经炎症失调在抑郁症的发病机制中起着关键作用。然而，跑步运动对海马神经炎症的影响以及抑郁症中小胶质细胞的数量和激活尚未得到研究。在这项研究中，大鼠经受慢性不可预测的压力 (CUS) 5 周，然后在跑步机上跑步 6 周。通过蔗糖偏好测试 (SPT) 评估大鼠的抑郁样症状。^{进行免疫组织化学和体视学以量化离子化钙结合接头分子 1 (Iba1) +}的总数小胶质细胞和免疫荧光用于量化 Iba1 ⁺ / 分化簇 68 (CD68) ^+的密度在海马体的子区域。通过 qRT-PCR 和 ELISA 测量海马中促炎细胞因子的水平。结果表明，跑步运动可以逆转 CUS 诱导的抑郁症大鼠对蔗糖的偏好降低。此外，CUS 增加了大鼠海马小胶质细胞的数量和小胶质细胞的激活，但跑步运动减弱了 CUS 诱导的海马小胶质细胞数量增加和海马齿状回 (DG) 小胶质细胞激活。此外，CUS显着增加了海马炎症因子的水平，而跑步运动抑制了海马炎症因子的增加。