simulated physiological stretchinduced proliferation of human bladder smooth muscle cells is regulated by mmps mechanical stimulation is an essential factor for organisms to develop normally in bladder development matrix metalloproteinases mmps play an important role through structure remodeling and regulating the cell proliferation in this study we investigated the simulated physiological stretch induced proliferation of hbsmcs mmpstimps expression in stretch and nonstretch groups hbsmcs were exposed to cyclic stretch with defined parameters 5 10 and 15 elongation the expression of mmps and timps in each parameter and nonstretch groups was examined at the transcriptional and translational levels respectively 5ethynyl2deoxyuridine edu assay was used to assess cell proliferation in the presence of the broad spectrum mmps inhibitor batimastat cells proliferation mmps and tissue inhibitors of metalloproteinases timps expression were assessed again compared with nonstretch group hbsmcs in stretch groups showed higher proliferation the expression of mmp1 2 3 7 was upregulated in stretch groups and it remained at the same high level in 10 and 15 stretch groups timp1 2 expression only increased under 15 stretch stretch resulted in elevated cell proliferation was abolished by batimastat in conclusion the proliferation of hbsmcs induced by stretch was resulted from the stretchinduced mmps expression and release