大黄酸调控自噬相关mTOR信号通路抗肾脏衰老的研究

Anti-renal senescence by Chinese medicine is a hotspot in the field of regimen. Senescence is closely related with kidney, thus anti-renal senescence is a necessary measure to delay senescence. Rhubarb and its bioactive ingredient rhein are commonly used in attenuating renal fibrosis and senescence. However, their underlining mechanisms are obscure. Activating mTOR signaling pathway, following suppressing its downstream autophagy signaling pathway, is a fundamental cause of senescence. Previous study found that autophagic protein LC3 and anti-senescence protein Klotho are vital targets of rhubarb in improving renal senescence in D-galactose induced model; further, mTOR signaling pathway is a key one in regulating autophagy. Supposing that rhein attenuates renal senescence by regulating autophagy-related mTOR signaling pathway. In this study, firstly, using the models of D-galactose-induced renal senescence in SD rats and NRK-52E cells, we purpose to clarify whether rhein could delay renal senescence via regulating autopahgy; and if so，we then aim to demonstrate the molecular mechanism of rhein in delaying renal senescence via regulating autophagy-related mTOR signaling pathway, by agonist, inhibitor and plasmid transfection technique of regulating mTOR signaling pathway. In sum，for the sake of the second developmental clinical application of an classical anti-renal fibrotic Chinese medicine in the field of regimen, we in the present study aim at revealing the new target of rhein in delaying renal senescence on the basis of the novel regulatory mechanism of renal senescence.

中药抗衰老是养生领域的研究热点，衰老与肾密切相关，抗肾脏衰老是延缓衰老的必要措施。大黄及其活性成分大黄酸是改善肾脏纤维化和抗肾脏衰老的常用药，但机制不明。mTOR信号通路活化而导致其下游自噬信号通路活性低下是引起衰老的根本原因。前期研究显示，自噬蛋白LC3和抗衰老蛋白Klotho是大黄改善D-半乳糖衰老模型鼠肾脏衰老的重要靶点，而mTOR信号通路是调控自噬的关键信号途径。假设大黄酸是通过调控自噬相关mTOR信号通路抗肾脏衰老。笔者首先建立D-半乳糖诱导的大鼠肾脏衰老模型和细胞衰老模型，在动物和细胞水平，阐明大黄酸干预自噬抗肾脏衰老的作用，其次借助质粒转染技术以及激动剂、抑制剂调控mTOR信号通路活性，证实大黄酸通过调控自噬相关mTOR信号通路抗肾脏衰老的分子机制。本项目基于对肾脏衰老分子调控机制的新认识，揭示大黄酸延缓肾脏衰老的新靶点，促进经典的抗肾脏纤维化中药在养生领域的二次开发应用。

随着中国人口老龄化的快速发展，衰老和衰老相关性疾病给家庭和社会都带来了沉重的负担，延缓衰老具有很好的现实意义。目前，衰老的内在机制还不明确，缺少有效的干预措施。自噬是调控衰老的重要机制。中医认为，血瘀是衰老的重要致病因素，因此，活血祛瘀是延缓肾脏衰老的重要方法。本研究证实了，D-半乳糖可以诱导肾脏衰老体内外模型，大黄酸和VE可以通过诱导Klotho蛋白的表达并减弱SA-β-gal染色的阳性面积来改善D-半乳糖诱导的肾小管细胞体外衰老和体内肾衰老。大黄酸和VE可以通过减少体内和体外自噬相关蛋白的表达并增加与mTOR信号相关的蛋白的表达来调节mTOR介导的自噬。因此，大黄酸类似于VE，可以通过调节mTOR介导的自噬减轻肾脏衰老。本研究以抗衰老为目的，以传统的中医理论为先导，以前期的基础研究为基石，进一步从深层次揭示大黄酸抗肾脏衰老的分子机制，从而，促进“祛瘀生新”代表中药活性成分大黄酸在中医养生学领域中的广泛应用。通过研究结论说明，靶向自噬和相关信号通路可能为老年患者的年龄相关性肾损伤提供新策略。