18α－GA通过上调蛋白酶体活性促进晚期骨髓间充质干细胞增殖

摘要

目的：明确18α－甘草次酸（18α－glycyrrhetinic acid，18α－GA）对晚期骨髓间充质干细胞（bone marrow mesenchymal stem cells ，BMSCs）衰老标志物和增殖能力的影响。方法：晚期BMSCs （≥14代）应用2．0 mg／L的18α－GA持续作用30 d，比较18α－GA组与DMSO组蛋白酶体活性；衰老相关β－半乳糖苷酶（ senescence－associatedβ－galactosidase，SA－β－Gal）染色和Western blot检测衰老相关蛋白p53、p21和p16的表达变化；CCK－8、BrdU掺入试验、流式细胞术和Western blot分别检测细胞增殖能力、细胞周期分布及细胞周期相关分子表达变化。结果：应用18α－GA后BMSCs蛋白酶体活性较DMSO组增高约0．2倍（P＜0．01）。18α－GA组SA－β－Gal阳性衰老细胞较DMSO组减少，且细胞着色浅淡；衰老相关蛋白p53和p21表达水平分别较对照组降低（P＜0．05）。 CCK－8实验及流式细胞术结果显示18α－GA组细胞增殖能力较DMSO组增高，S期细胞显著增多（P＜0．05），18α－GA组BrdU染色阳性细胞率较DMSO对照组增高（P＜0．05）。18α－GA组细胞周期相关蛋白cyclin D1及CDK4表达水平分别较DMSO组增高（P＜0．05）。结论：18α－GA可激活晚期BMSCs蛋白酶体活性延缓细胞衰老，并且可能通过上调细胞周期相关蛋白表达水平促进晚期BMSCs增殖。%AIM:To investigate the effect of 18 alpha-glycyrrhetinic acid (18α-GA) on delaying the senescent progress and promoting the proliferation in late-passage bone marrow mesenchymal stem cells ( BMSCs ) .METHODS:Late-passage BMSCs were incubated with 2.0 mg /L 18α-GA or the same volume of DMSO for 30 d, and the cells were harvested to determine the proteasome activity .The expression of senescence-related proteins p53, p21 and p16 was detec-ted by senescence-associated β-galactosidase ( SA-β-Gal) staining and Western blot .The cell proliferation , the expression level of cell cycle-related proteins and cell cycle distribution of the cells were measured by CCK -8 assay, BrdU incorpora-tion, Western blot and flow cytometry.RESULTS:Compared with DMSO group, the proteasome activity in 18α-GA group increased significantly by about 0.2 times (P<0.01).SA-β-Gal-positive cells in 18α-GA group decreased, and cell stai-ning was lighter.The contents of p53 and p21 in 18α-GA group were decreased (P<0.05).The results of CCK-8 assay showed that the A value in 18α-GA group was 0.3 times higher than that in DMSO group (P<0.01).BrdU incorporation showed the increased proliferation in 18α-GA group compared with DMSO group ( P<0.05).The cells in G1 phase in 18α-GA group decreased significantly compared with DMSO group , while the cells in S phase increased significantly ( P<0.05).The expression level of cyclin D1 in 18α-GA group was 2.8 times higher than that in DMSO group (P<0.01), and the CDK4 level was 1.4 times higher than that in DMSO group (P<0.05).CONCLUSION:Activation of the pro-teasome activity by 18α-GA delays the aging process in the BMSCs and promotes the cell proliferation via up -regulation of the cell cycle-related proteins .