Objective       To investigate the effect of histone acetylation on the differentiation capacity of bone marrow mesenchymal stem cells (BMSCs) directly co-cultured with bladder smo

oth muscle cells (BSMCs).       Methods       Density gradient centrifugation and collagenase digestion were used to train the rat BMSCs and BSMCs to the 3rd passage. After the cells were identified

BMSCs co-cultured with BSMCs were regarded as experimental cells

while the cells cultured alone as the control cells. Immunofluorescence assay was used to detect the expression of BMSCs landmark proteins

α-smooth muscle actin (α-SMA)

smooth muscle myosin heavy chain (SM-MHC)

and calponin in the 2 kinds of BMSCs. Western blotting was adopted to detect the protein levels of α-SMA and calponin. Micrococcal nuclease (MNase) was used to detect the promoter regions of the 3 marker genes for open chromatin

while ChIP technical analysis was used to detect the histone acetylation levels in the promoter regions of α-SMA and SM-MHC

and the effects of the levels on BMSCs to smooth muscle differentiation were determined.       Results       Our obtained primary rat BMSCs were positive to CD29 (99.8%)

negative to CD31 and CD45 (positive rate of 6.30% and 1.04%). Immunofluorescence assay showed the expression of the 3 BMSCs landmark proteins was increased with time elapsing. Western blotting showed that the protein levels of α-SMA and calponin were significantly higher in experimental cells than in control cells with the elapse of co-culture time. MNase assay displayed that experimental BMSCs had significantly higher chromatin nuclease sensitivity in promoter regions than the control cells. ChIP showed the experimental BMSCs had significantly higher H4 acetylation level in the promoter regiong of α-SMA

SM-MHC and calponin when compared with the undifferentiated cells (

P

<

0.05).       Conclusion       The enhanced histone acetylation promotes BMSCs differentiation to BSMCs.