目的 探讨延缓衰老基因Klotho对骨髓间充质干细胞（BMSCs）增殖和分化的影响。 方法 体外条件下培养大鼠骨髓间充质干细胞，构建分泌型Klotho(sKL)过表达的BMSCs。Western blotting检测细胞及培养基中sKL的表达；MTT法检测细胞增殖能力；Western blotting检测衰老标志物P53、P21蛋白的表达。利用成骨诱导液定向诱导BMSCs向成骨细胞分化，应用碱性磷酸酶(ALP)染色鉴定成骨效果；利用成脂诱导液定向诱导BMSCs向脂肪细胞分化，应用油红O染色鉴定成脂效果。 结果 Western blotting结果显示，sKL组细胞和培养基中sKL蛋白表达显著上调（P<0.05），P53、P21表达显著下调（P<0.05）；MTT结果显示，各组细胞吸光度值（A值）差别无显著性（P>0.05），sKL组成骨及成脂能力明显强于对照组（P<0.05）。 结论 sKL增强了大鼠BMSCs的延缓衰老能力，对BMSCs的成骨分化和成脂分化产生一定的促进作用，而对BMSCs的增殖无显著影响。

Objective To investigate the effect of antiaging gene Klotho on the proliferation and differentiation of rat bone marrow mesenchymal stem cells(BMSCs). Methods Rat BMSCs overexpressing secreted Klotho(sKL) were cultured and constructed in vitro. MTT assay was used to detect the cell proliferation. Western blotting was used to measure the expression of sKL in the cells and medium of three groups. As markers of aging, P53 and P21 in three cells were also detected. BMSCs were induced to osteogenic differentiation by osteogenic induction medium, the result of differentiation was observed by alkaline phosphatase(ALP) staining; BMSCs were induced to adipogenic differentiation by adipogenic induction medium, the result of differentiation was identified by oil red O staining. Results Western blotting showed that the expression of sKL increased significantly in the sKL group (P<0.05), in addition, the expression of P53 and P21 decreased significantly in the sKL group(P<0.05). MTT assay indicated that there was no significant differences about absorbance value between sKL group and control group(P>0.05). The ability of osteogenic differentiation and adipogenic differentiation was significantly stronger than that of the control group(P<0.05). Conclusion sKL effectively enhances the anti-aging ability of BMSCs, meanwhile it also promotes osteogenic and adipogenic differentiation of BMSCs. Besides, this study also suggests that Klotho may have no effect on the proliferation of BMSCs.