车前草总黄酮对大鼠膀胱和尿道平滑肌收缩反应的影响

Impact of Total Flavonoids of Plantago Asiatica L. on Contraction Response of Bladder and Urethral Smooth Muscles in Rats

目的研究车前草治疗泌尿系结石的可能机理。方法水负荷法筛选尿量敏感大鼠40只,随机分为空白对照组、阳性对照组和黄酮低、中、高剂量组,每组8只。各实验组大鼠禁食不禁水15 h后,给予水负荷生理盐水30 ml/kg,30 min后阳性对照组给予氢氯噻嗪片11.6 mg/kg灌胃,黄酮低、中、高剂量组分别给予车前草总黄酮120、240、480 mg/kg灌胃,空白对照组给予等体积纯净水灌胃。第1天给药后压迫大鼠下腹,使膀胱中余尿排尽,然后置代谢笼中收集6 h尿液,比较各组大鼠1、2、4、6 h时尿重量,并检测尿液中Na+、Cl-、K+离子的含量。连续给药7天后,以乙酰胆碱和去甲肾上腺素为工具药,比较各组大鼠膀胱及尿道平滑肌收缩反应情况。结果与空白对照组比较,黄酮低、中、高剂量组均可显著增加大鼠尿重量及尿液中Na+、Cl-的含量(P<0.05,P<0.01),对K+含量无明显影响(P>0.05)。黄酮低、中、高剂量组大鼠离体膀胱平滑肌收缩率、尿道平滑肌抑制率较正常对照组和阳性对照组升高(P<0.01)。结论车前草总黄酮利尿作用明显,又可显著增强膀胱的排泄作用,其利尿兼促排的作用可能是车前草治疗泌尿系结石的重要机理之一。

Objective To explore the possible mechanism of plantago asiatica L. treating urinary calculus.Methods Forty urine volume sensitive rats were selected by water load method and randomized into blank control group,positive control group,low-dose,middle-dose and high-dose flavonoids groups,8 rats in each group. Rats in every group were given water but fasting. After 15 hours,all rats were given water load normal saline 30 ml / kg. After30 minutes,positive control group were given hydrochlorothiazide tablets 11. 6 mg / kg by gavage; flavonoids low,middle and high dose groups were given total flavonoids of plantago asiatica L. 120,240,480 mg / kg by gavage.Blank control group were given isovolumetric pure water by gavage. On the first day,after administration,pressed lower abdomen to exhaust residual urine in bladder,put rats in metabolic cages,collected 6h urine,compare urine weight at 1,2,4,6 h; and detected the contents of urine Na＋,Cl-,and K＋. After 7 days of continuous administration,taking acetylcholine and noradrenaline as tool drug,compared the contraction response of bladder and urethral smooth muscles. Results Compared with control group,urine weight and content of urine Na＋and Cl-in flavonoids low,middle and high dose groups increased significantly（ P〈0. 05,P〈0. 01）; there was little impact on K＋content（ P〈0. 05）. Contraction rate of in vitro bladder smooth muscles and inhibition rate of urethral smooth muscles in flavonoids low,middle and high dose groups were higher than those in control group and positive control group（ P〈0. 01）. Conclusion Total flavonoids of plantago asiatica L. have obvious diuretic effect and could enhance bladder excretion function. Its diuretic and excretive effect might be one of the important mechanisms of plantago asiatica L. treating urinary calculus.