Study on the changes of mammalian target of rapamycin with aging in rat kidneys / 中华老年医学杂志

ABSTRACT

ObjectiveTo investigate the changes in mammalian target of rapamyein (mTOR) with aging in rat kidneys.MethodsMale Wistar rats at the ages of 3, 12, 24 months were used for this study. Therenaltissuesandmesangialcellswereprocessedfor senescenceassociated β-galactosidase (SA-β-gal) staining. The expression and location of roTOR in kidneys and mesangial cells were studied by immunohistochemistry and immunocytochemistry, respectively. The mRNA and protein levels of the roTOR and p-roTOR were detected by Western blot assay and RT-PCR,respectively.ResultsThe expression of neutral β-galactosidase activity was increased in kidneys and mesangial cells with advancing age. Percentages of SA-β-gal staining positive ceils were (11.9±3.6)% versus ( 39.0±4.0)% versus ( 86.9±7.4) % in young, middle and aging glomerular mesangial cells (P<0.05). The mTOR staining appeared in the mesangial matrix and interstitium in kidneys, while the mTOR protein showed localization in cytoplasm and nucleus in mesangial cells. The staining intensity of mTOR in kidneys and mesangial cells in aged rats was markedly increased as compared to that in young and middle aged rats (P<0.05). The mRNA level of roTOR was significantly increased in kidneys and mesangial cells of agedrats versus young and middle aged rats,meanwhile, the roTOR and p-mTOR protein expressions were dramatically increased with advancing age (P<0.05 ).ConclusionsmTOR expression is increased with aging, which may play an important role in the aging process of kidneys.