Signal Pathways Involved In The Regulation From Carbon Nanotubes On The Apoptosis Of BMSCs In Hunger

In present study,cell apoptosis model by serum starvation were established in bone marrow mesenchymal stem cells from rat.The serum starvation is to simulate the nutritional deficiencies during the tissue regeneration,The effects of carbon nanotubes on the cell apoptosis were investigated by studying the changes of cell viability,cell apoptosis rate and the expressions of related biological signal molecules after co-culture of cells and single-walled carbon nanotubes.The flill bone marrow adherence method was employed to isolate and culture rat BMSCs.To further purifying the cells,the culture media were changed frequently by the 1 d,2 d,5 d and 7 d,and the digestion time is limited to 1min.The homogeneous morphology and the high proliferative ability in isolated cells were achieved in present study.Serum deficiency is one of the important factors in the survival of donor BMSCs in cell therapy.The aim of this study was to assess the effect of serum deficiency on the apoptosis of BMSCs.The apoptosis of BMSCs was examined by Hoechst 33342/PI staining,and the expression of apoptotic-related biomarkers was analyzed by western blotting.The results showed that the apoptosis of BMSCs appeared within 72 h after culture in serum-free media.Furthermore,the expressions of Bax,Bcl-2,Casepase-3,Casepase-8,GRP78 and CHOP proteins were changed during the serum-free culture.The data indicate that mitochondria pathway,the exogenous apoptosis pathway and the ER stress pathway are involved in BMSCs apoptosis.The enhancement of CHOP protein expression and the decrease of Bcl-2 protein expression were significantly synergistic,indicating that three must be crosstalks between mitochondrial and endoplasmic reticulum(ER)responses.BMSC were co-cultured with different kinds of single-walled carbon nanotubes in the serum-free media.Cell apoptosis was detected by Hoechst 33342/PI staining,and the expression of apoptosis-related biomedical molecules was analyzed by western blotting.The results showed that carbon nanotubes exacerbated the apoptosis of BMSCs in serum-free cultures.Moreover,carboxylated short single-walled carbon nanotubes had the most significant induction effects on cell apoptosis.The changes of expressions of Bax,Bcl-2,Casepase-3,Casepase-8,Caspase-9,GRP78 and CHOP proteins were involved in the apoptotic mechanisms,suggesting that single-walled carbon nanotubes activated the mitochondrial pathway,the exogenous apoptosis pathway and endoplasmic reticulum stress pathway simultaneously.