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 .
ABSTRACT
Objective To explore the effect of D-galactose(D-gal) on murine pancreatic injury and its pathogenesis.Methods C57BL/6J mice were randomly divided into control group and D-gal model group [D-gal 120 mg/(kg · d) for 42 days].On the 2nd day after drug injection completed,the peripheral blood was taken for measuring the level of fasting blood glucose(FBG) and fasting insulin(FINS);and then the organ index of pancreas was calculated by the ratio of pancreatic wet weight(mg) and mouse body weight(g);HE stain was routinely prepared to observe the histologic structure of pancreatic tissue;the TEM was used to analyze ultrastructural changes of pancreatic cells;the pancreatic frozen sections were prepared to test senescence-associated β-galactosidase (SA-β-gal) and its relative absorbance(RA) of positively stained cells in the pancreatic islets;immunohistochemistry assays to study advanced glycation end products (AGEs) and its RA;pancreas tissue homogenate was made to detect the content of superoxide dismutase(SOD),malonaldehyde(MDA) and total antioxidant capacity(T-AOC).Results In D-gal group mice,the FBG increased(P＜0.05) and FINS reduced;pancreas wet weight and organ increased obviously (P＜0.01);light microscopic structure of the pancreas presented without typical pathologic change,however the single nucleated cell's area within the islet was increased significantly(P＜0.05);the pancreas endocrine and exocrine cells were showed the ultrastructure damaged and lipofuscin formation increased;the RA of positive pancreas cells in SA-β-gal staining increased(P＜0.05);the RA of AGEs positive regional expression markedly increased (P＜0.01);the content of SOD and T-AOC decreased (P ＜ 0.05),the content of MDA increased (P ＜ 0.01).Conclusions Aging mice model replicated by D-gal can cause the pancreatic injury,its mechanisms may be closely related to oxidative injury of pancreatic cells caused by D-gal.
ABSTRACT
Clinic probation teaching is an important part of medical education practice, whose teaching effect andquality have impact on the quality of cultivation for medical students. To solve the existing problems, Gannan MedicalCollege has combined the single clinic probation with social practice activities, expanded the probation teaching area,made the full use of students' capability, reformed the traditional probation teaching pattern, defined teaching objectivereasonably, which gives rise to the improvement in clinic teaching quality.