ABSTRACT
Objective To establish an aging model of rat bone marrow stromal cells (BMSCs) in vitro and in vivo, in order to study the senescence biology of aging BMSCs .Methods The control cell group ( in vitro):isolating, puri-fying and culturing BMSCs from healthy male SD rats .collecting the third generation ( P3) of BMSCs for analysis . The aging model group (in vitro):the P3 BMSCs were incubated with D-Galactose (D-Gal, 30 g/L) for 48 hours. The aging rat model group ( in vivo): the rats were given 120 mg D-Gal by the way of daily neck subcutaneous injection for 42 consecutive days .The control rat group ( in vivo):the rats were administrated with the same volume of saline for the same times .On the second day after the aging model was established , the BMSCs were collecting and culturing for study.1)The proliferative potency was detected by cell counting Kit-8(CCK-8);the distribution of cell cycle and apoptosis was detected by flow cytometry (FCM);2)the ratio of aging BMSCs was examined by the senescence-associated β-Galactosidase(SA-β-Gal) staining;3)malonaldehyde(MDA) content and total super-oxide dismutase(SOD) was examined activity by enzymatic assay; the level of reactive oxygen species (ROS) by DCFH-DA fluorescent staining was counted with FCM;4 ) the expression level of senescence-related signaling was proteins of P16 , P21 , P53 , CDK2 and cyclin D by Western blot .Results Compared with the matched control group, the BMSCs of aging model group displayed a significant decrease in proliferation; the BMSCs were held in G1 phase arrest as the proportion of the cells in G 1 phase increased , while that decreased in S phase ( P<0.05 );and the positive ratio of SA-β-Gal stained BMSCs also significantly increased ( P <0.05 ); BMSCs in the aging model group showed an increasing level of ROS and MDA , meanwhile a decline in total SOD activity was decreased (P<0.05);P16,P21 and P53 protein expression in aging BMSCs was obviously enhanced (P<0.05), at the same time the expression of CDK2 and cyclin D was also decreased ( P<0.05 ) .Conclusions D-Gal can be used to develope an aging model of BMSCs .It acts through up-regulation of expressions of aging-related proteins and in-hibition of oxidative stress injury and chronic inflammation .