骨髓间充质干细胞修复衰老大鼠肾脏损伤的研究

Study on the repair effect of bone-marrow mesenchymal stem cells on kidney damage in aging rat

目的探讨骨髓来源的间充质干细胞对衰老模型大鼠肾脏衰老损伤的修复作用及机制。方法体外培养、鉴定SD大鼠骨髓来源的间充质干细胞（mesenchymalstemcells，MSC）。将健康SD大鼠随机分为正常对照组、衰老模型组和MSC治疗组。通过每日给予大鼠注射D-半乳糖（剂量为400mg/kg），制备衰老模型。MSC治疗组通过给予衰老模型大鼠输注3×106个MSC，以制备MSC治疗组。采用表达绿色荧光蛋白(greenfluorescentprotein，GFP）的腺病毒载体标记MSC，观察MSC在肾脏的迁移情况。检测各组大鼠肾组织的谷胱甘肽过氧化酶（glutathioneperoxidase，GSH-Px）活性，晚期糖基化终产物(advancedglycationendproducts，AGEs)的含量；HE染色行肾组织病理学检查；应用实时定量逆转录PCR法检测肾组织中衰老相关基因P53和P21mRNA的表达。结果GFP标记的MSC细胞移植给衰老模型大鼠后，能向肾组织迁移。与对照组相比，衰老模型组肾组织GSH-Px活性降低，AGEs含量增加(P<0.05)；而MSC治疗组GSH-Px活性升高，AGEs含量减少(P<0.05)。病理切片显示模型组大鼠肾脏损伤严重，而MSC治疗组大鼠的肾脏损伤有明显修复。MSC能够调控衰老相关基因的表达，MSC组肾组织P53和P21mRNA表达降低(P<0.05)。结论骨髓MSC能够减少衰老大鼠的肾脏损伤，MSC修复衰老损伤的机制可能是通过抑制氧化应激损伤，降低P53和P21基因的表达。

Objective To investigate the repair effect of bone-marrow mesenchymal stemcells on the kidney of aging model rats and its relative mechanism. Methods Bone marrowmesenchymal stem cells (MSC) were isolated and identified in vitro. Healthy SD rats wererandomized into three groups, including normal control group, aging model group and MSCgroup. The rats were injected with D-galactose at 400mg/kg every day to establish the agingmodels. The 3×106 MSC cells were injected into the aging models rats via the tail vein toestablish MSC group, and the MSC were transfected by adenovirus vector expressing greenfluorescent protein (GFP) to construct GFP-MSC. Then the migration of MSC in kidney ofaging model was examined by fluorescence microscope. The activity of glutathione peroxidase(GSH-PX),the content of advanced glycation end products (AGEs) in kidney were detected.The pathological morphological changes of kidney tissue were observed by hematoxylin andeosin (HE) staining. The expression of P53and P21 mRNA in kidney tissue was detected withreal-time PCR.Results MSC marked by GFP could migrate into the kidney of aging model rats.Compared with control group, the activity of GSH- PX decreased, and the content of AGEsincreased in the aging model group (P<0.05). While in MSC group,the activity of GSH-PXincreased,and the content of AGEs decreased significantly (P<0.05). Aging could impair kidney tissue gradually. The treatment of MSC improved the pathological damage of kidney, comparedwith aging group. In addition, MSC can regulate senescence associated mRNA expression. MSCgroup had lower P53 and P21 mRNA levels compared with model group (P<0.05).ConclusionTransplantation of MSC can reduce kidney damage induced by D-galactose. MSC can inhibit theoxidative stress, reduce the expression of P53 and P21 mRNA. Thus, it plays a key role in theanti-aging on rats’ kidneys.