葛根素对糖尿病性白内障大鼠晶状体上皮细胞的保护作用

Protective effects of puerarin on lens epithelial cells in rat diabetic cataract

目的 通过葛根素全身与局部用药治疗糖尿病大鼠白内障疗效的比较,探讨葛根素的最佳用药途径.方法 实验研究.将192只健康无热源SD雄性大鼠按随机数字表法均分为对照组、链脲佐菌素（STZ）组、腹腔注射组及球旁注射组.采用STZ制作大鼠糖尿病模型.对照组与STZ组大鼠腹腔注射生理盐水,腹腔注射组和球旁注射组分别注射葛根素.分别于注射后20、40、60 d检查大鼠的全身情况和晶状体形态;光镜下观察晶状体上皮细胞（LEC）的形态;同时采用生物化学方法检测一氧化氮（NO）含量与一氧化氮合酶（NOS）活性;采用免疫印迹法及反转录聚合酶链反应法检测iNOS蛋白与iNOS mRNA在晶状体中的表达;应用透射电镜和扫描电镜观察LEC的亚细胞结构变化.数据采用两因素析因设计方差分析.结果 注射后20、40、60 d,对照组大鼠晶状体均透明,STZ组大部分晶状体核及核周皮质出现混浊,部分晶状体完全混浊;腹腔注射组和球旁注射组大鼠晶状体仅轻度混浊;光镜下LEC形态对照组无改变,STZ组细胞体积缩小,胞核浓缩,赤道部皮质出现大量特征性空泡性改变;而60 d腹腔注射和球旁注射组大鼠LEC形态为STZ组20 d时的改变;晶状体NO与NOS含量,iNOS蛋白与iNOS mRNA的表达对照组一直处于极低水平,未见表达及上调;随实验时间延长,STZ组NO2-/NO3-含量逐渐增多,NOS活性、iNOS蛋白与iNOS mRNA的表达与上调逐渐增强,在20、40及60 d均明显高于对照组（F=684.09,P＜0.01）,腹腔注射及球旁注射组以上指标在各个时限点均明显低于STZ组,但仍高于对照组（F=1938.62,P＜0.05）.透射电镜和扫描电镜观察,对照组大鼠LEC未见异常,STZ组LEC呈异常改变且病变逐渐加重.线粒体肿胀变性,粗面内质网结构不清,部分核固缩且大小不一,核周间隙加大（F值分别等于14 590.65和177.85,P＜0.001）.晶状体纤维间窝球状结构逐渐消失,膜破裂脱落堆积形成球样小体;腹腔注射组和球旁注射组大鼠LEC细胞核与晶状体纤维正常,但可见少许线粒体肿胀、内质网扩张及细胞间隙增宽.结论 葛根素腹腔注射与球旁注射两种给药途径对糖尿病大鼠LEC均有保护作用并且疗效相当.

Objective The therapeutic effects of general and local applications of puerarin in the treatment of streptozotocin （STZ）-induced rat diabetic model were compared. Methods Experimental research. We equally divided normal Sprague-Dawley （SD） rats into a STZ group, a peritoneal injection group, a peribulbar injection group and a control group. STZ, peritoneal injection and peribulbar injection groups were first treated with STZ. Subsequendy, the STZ group was injected with normal saline intraperitoneally, while in the later two groups puerarin was injected through peritoneal and peribular routes,respectively. Control group only received peritoneal injection of saline. The morphology of lens epithelial cells （LEC） and their subcellular structure were examined by bright-field microscopy, transmission electron microscopy （TEM） and scanning electron microscopy （SEM） 20, 40 and 60 days after the injection.Nitrogen oxide （NO） and nitric oxide synthase （NOS） were measured by biochemistry methods. Finally,inducible nitric oxide synthase （iNOS） protein and mRNA levels were monitored by Western blot and RTPCR, respectively. Data was processed with two factorial experiment analysis of variance. Results Twenty to sixty days after the injection, marked or complete lens opacities appeared in the STZ group, whereas only slight opacities appeared in the lens in peritoneal and peribulbar puerarin groups and the lens in the control group remained clear. At the 20th, 40th and 60th day after the injection, optical microscope detected pathological changes of LEC in the STZ group. The cell volume was decreased with a dense nucleus and many bubbles appeared around the equator ares. Under TEM, enlargement of cell gap, vacuoles in the cytoplasm, swelling of mitochondria and unclear structure of rough endoplasmic reticulum appeared in the LEC of the STZ group. Part of the nucleus was in karyopyknosis and peripheral nucleus gap was enlargement. Under SEM, normal fiber conjunction structure of the lens disappeared, fibers were swelling,part of fiber membranes were discontinuous, detached, and accumulated in certain areas. Mild lens opacities detected by bright-field microscope were developed in peritoneal and peribulbar puerarin injection groups.Nucleus and fibers in the lens cells of both groups appeared to be normal, with minor swelling of mitochondria, minor enlargement of endoplasmic reticulum and slight increase of intracellular space. NO,NOS and iNOS protein and mRNA of the lens were increased and up-regulated in STZ group. In the other two groups only minor changes were present and the changes were significantly less than that of the STZ group but greater than that in the control group. Conclusion Peritoneal and peribulbar injection of puerarin have similar therapeutic effects in the treatment of rat diabetic cataract.