Inhibitory effect of puerarin on activity of isolated bladder detrusor muscle in rats

Objective To investigate the effects of puerarin on the activity of bladder detrusor muscle in rats and explore its mechanism. Methods Complete spinal cord transaction was established by cutting out of dura at T10 in 56 female SD rats and rats were randomly allocated into puerarin 10 mg, puerarin 20 mg, puerarin 30 mg and control groups.Each group was intraperitoneally injected with puerarin(10 mg, 20 mg, 30 mg)and 0.9% sodium chloride, respectively, once a day for 30 days.Then Urodynamic monitor was performed to evaluate maximum bladder capacity(MBC), bladder leak point pressures(BLPP)and contraction frequency(CF)in rats of each group, western blot was used to measure the expression of subtype of T-type calcium channelα1G and C-kit under interventions of puerarin in each group. Results Urodynamic showed that MBC in puerarin group was(3.375 0±0.074 7)ml and(0.804 9±0.114 1)ml in saline group, BLPP and CF in puerarin group were(23.82±0.31)cmH₂O and(5.24±0.12)/s respectively, which were significantly lower than saline group (29.62±1.82)cmH₂O, (8.72±0.38)/s, P＜0.01.MBC in puerarin 30 mg, puerarin 20 mg, puerarin 10 mg groups were(3.982 6±0.162 7)ml, (3.261 9±0.135 2)ml and(2.836 7±0.216 5)ml respectively, BLPP in puerarin 10mg, puerarin 20mg, puerarin 30mg groups were(25.08±1.71)cmH₂O, (23.78±1.37)cmH₂O and(22.68±1.91)cmH₂O, which showed successively decline, CF in puerarin 10 mg, puerarin 20 mg, puerarin 30 mg groups were(6.13±0.15)/s, (5.21±0.22)/s, (4.34±0.12)/s, which showed significant decrease(P＜0.01).Western blot showed that the expression quantity of α1G in puerarin(10, 20, 30 mg)groups were(0.832±0.065), (0.541±0.051)and(0.324±0.059), and the expression quantity of C-kit in puerarin(10, 20, 30 mg)groups were(0.673±0.059), (0.519±0.019), (0.316±0.038)with significant decrease(P＜0.01). Conclusion Puerarin can inhibit the contraction of isolated bladder detrusor muscle in rats and its mechanism may relate with the down-regulation of C-kit and α1G expression in bladder.