Effects of Different Sustained Hydrostatic Pressures on Connexin 43 in Human Bladder Smooth Muscle Cells

Abstract

Objectives: To cultivate primary human bladder smooth muscle cells (hBSMCs) in vitro and to study the influences of different sustained hydrostatic pressures upon hBSMCs in terms of cell proliferation and expression of gap-junction connexin 43 (Cx43). Methods: hBSMCs were exposed to 0, 20, 40, 60, 80 and 100 cm H₂O sustained hydrostatic pressures for 6, 12, 24 and 72 h, respectively. hBSMC proliferation was quantified with Cell Counting Kit-8 (CCK-8) afterwards. Immunofluorescence staining and Western blotting were employed to determine hBSMC Cx43 expression. Results: hBSMC proliferation increased with time (6–72 h) without significant differences between pressure levels at each time point. Expression of Cx43 on Western blotting and immunofluorescence staining was similar under varied pressures for 6 and 12 h while seeing significant decreases under hydrostatic pressures >60 cm H₂O for 24 h or pressures >40 cm H₂O for 72 h. Conclusions: Different sustained hydrostatic pressures (<100 cm H₂O) bear no significant effects on proliferation of hBSMCs. Interestingly, hydrostatic pressures above the physiological level seem to cause the gap junctions of hBSMCs to decrease significantly and affect the cellular functions in the cultivation group over a longer period of time.