ObjectiveTo explore the relationship between the pressure level within the scope of promoting proliferation and cell injury of human bladder smooth muscle cells (HBSMCs). MethodHBSMCs in vitro were divided into the experimental group and control group. The cells in the experimental group were exposed to 40 cm H2O (1 cm H2O=0.098 kPa) pressure and those in the control group were cultured in normal condition for 24 hours. We investigated the cell morphology and cytoskeleton with indirect immunofluorescence staining for α-actin. Propidium iodide (PI) staining was applied to evaluate the level of cell apoptosis. ResultsThere was no significant difference in the cell morphology between the two groups. However, the expression of α-actin in the experimental group[(50.93±1.99)%] was significantly reduced comparing with that in the control group[(24.70±1.61)%] (t=32.404, P<0.001). The results of PI staining showed that compared with the control group[(3.50±2.12)%], the number of PI staining positive cells in the experimental group [(9.00±1.41)%] was significantly higher (t=6.110, P<0.001). ConclusionsPressure condition can promotes cell proliferation, but at the same time, it can also lead to cell injury of HBSMCs.