RESUMO
AIM:To evaluate the effect of α2-macroglobulin(α2M) against X-ray induced obstacle on osteo-genic differentiation of human bone marrow mesenchymal stem cells(hBMMSCs). METHODS:hBMMSCs were cultured in vitro. The 4th generation of hBMMSCs was irradiated with 8 Gy X-ray,then induced osteogenic differentiation and trea-ted with different concentrations of α2M(0.5 and 1.0 g/L). The alkaline phosphatase(ALP) activity and the mRNA ex-pression of runt-related transcription factor-2 (RUNX2) were detected on day 7 after osteogenic induction. The protein ex-pression of osteoglycin (OGN) was evaluated by Western blot on day 14 after osteogenic induction. The formation of calci-um nodules was detected by alizarin red staining on day 21 after osteogenic induction. The activity of superoxide dismutase (SOD) and the protein expression of MnSOD of irradiated hBMMSCs with 8 Gy X-ray were determined at 24 h after α2M treatment. RESULTS:Compared with 8 Gy X-ray group,the activity of ALP,the mRNA expression of RUNX2,the pro-tein expression of OGN and MnSOD,as well as SOD activity were higher than those in the hBMMSCs treated with α2M at 0.5 and 1.0 g/L after 8 Gy X-ray irradiation,and the calcium nodules were also increased. CONCLUSION:α2M signifi-cantly improves the osteogenic differentiation ability,the SOD activity and MnSOD protein expression of hBMMSCs after ra-diation injury.
RESUMO
Objective To establish an assay for detecting α2-macroglobulin activity in Cohn fraction Ⅳ.Methodsα2-M reacted with trypsin to form α2-M-trypsin complex.After the chromogenic substrate Na-benzoyl-DL-arginine 4-nitroanilide hydrochloride ( BAPNA) was added, absorption at 410 nm was detected with the microplate reader .α2-M activity in Cohn fractionⅣwas quantitatively detected according to the established standard curve of plasma α2-M activity. Result Several critical parameters in this assay were optimized .A standard curve of plasma α2-M activity was established . According to this standard curve ,α2-M activity in Cohn fraction Ⅳsample was detected to be 1.578 PU/ml.Conclusion Using normal human plasma as the reference material , theα2-M activity in Cohn fractionⅣcan be detected through chro-mogenic substrate assay.This study provides a simple method to detect α2-M activity during the purification process of α2-M from Cohn fraction Ⅳ.
