枸杞对大鼠肾草酸钙结石生成的干预效果及其机制

Effects and mechanism of Fructus lycii on renal calcium oxalate stone formation in rats

目的研究枸杞对大鼠肾草酸钙结石生成的干预效果及可能机制。方法Wistar大鼠根据诱石方式(吸烟或饮用乙二醇或两者联合)、枸杞浸泡剂干预与否以及干预浓度(10%或25%)进行分组,设立空白对照组,每组10只。分组处理40d后,收集24h尿液并采集肾组织样本。检测尿液中钙、草酸及枸橼酸浓度;观察各组大鼠肾小管草酸钙结晶沉积情况并进行等级评分;检测肾组织脂质过氧化物丙二醛(MDA)含量及总超氧化物歧化酶(T-SOD)活性;TUNEL染色观察肾小管细胞凋亡并计算凋亡指数。结果吸烟联合乙二醇诱石组尿钙浓度明显高于空白对照组(P<0.01);单纯饮用乙二醇和吸烟联合乙二醇诱石组大鼠肾小管草酸钙结晶评分、肾组织MDA含量及肾小管上皮细胞凋亡指数均高于空白对照组,而尿液中枸橼酸浓度和肾组织T-SOD活性均低于空白对照组。10%和25%枸杞浸泡剂干预可显著降低吸烟联合乙二醇诱石组大鼠尿钙浓度(P<0.01);同时使单纯饮用乙二醇和吸烟联合乙二醇诱石组大鼠肾小管草酸钙结晶评分、肾组织MDA含量及肾小管上皮细胞凋亡指数下降,而尿液中枸橼酸浓度和肾组织T-SOD活性升高。枸杞浸泡剂两种浓度间未见明显量效关系。结论枸杞能有效抑制吸烟和(或)乙二醇诱导的大鼠肾草酸钙结石的生成,其机制可能与降低肾组织内自由基水平,抑制肾小管上皮细胞凋亡,以及减少尿液中促石成分而增加抑石成分有关。

Objective To investigate the effects and possible mechanism of Fructus lycii on renal calcium oxalate stone formation in rats. Methods Wistar rats were divided into several groups according to different stone inducer （cigarette smoking, ethylene glycol solution drinking or combination of both）, either Fructus lycii infusion interference or not and different interfering concentrations （10% and 25%）. Besides, a blank control group was set. After treatment for 40 d, 24 h urine was collected, and renal tissue samples were obtained. The concentrations of calcium, oxalate and citric acid in urine were measured. The deposit condition of calcium oxalate crystals in nephric tubules was observed and scored. The levels of malondialdehyde （MDA） and activity of total-superoxide dismutase （T-SOD） in renal tissues were detected. Apoptosis cells in kidney were observed with TUNEL staining, and index of apoptosis was calculated. Results Compared with blank control group, the urine calcium concentration in group of combination of cigarette smoking and ethylene glycol solution drinking were significantly higher （P〈0.01）, the scores of calcium oxalate crystals in renal tubules, the levels of MDA in renal tissues and the index of apoptosis of renal tubule epithelial cells in groups of ethylene glycol solution drinking and combination with smoking were higher, while the concentrations of citric acid in urine and activity of T-SOD in renal tissues were lower. Ten percent and 25% Fructus lycii infusion significantly decreased the urine concentrations of calcium in group of combination of cigarette smoking and ethylene glycol solution drinking （P〈0.01）, decreased the scores of calcium oxalate crystals in renal tubules, the levels of MDA in renal tissues and the index of apoptosis of renal tubule epithelial cells in groups of ethylene glycol solution drinking and combination with smoking, and increased the concentrations of citric acid in urine and activity of T-SOD in renal tissues. There was no significant dose-effect relationship between two concentrations of Fructus lycii infusion. Conclusion Fructus lycii infusion can effectively inhibit the formation of renal calcium oxalate stone in rats with smoking and/or ethylene glycol drinking by reducing the free radicals and apoptosis of renal tissue, decreasing the concentration of elements for stone formation and increasing the concentration of elements for inhibition of stone formation in urine.