灵芝孢子干预糖尿病大鼠睾丸组织线粒体自噬及细胞的凋亡

Effect of ganoderma spore on mitochondrial autophagy and apoptosis in testicular tissue of diabetic rats

背景:男性生殖障碍作为糖尿病的常见并发症近年来受到越来越多的关注。灵芝孢子具有降糖、抗氧化、抗炎等功效,但其对于糖尿病睾丸组织的调控机制尚未完全阐明。目的:探讨灵芝孢子对糖尿病大鼠睾丸组织PTEN诱导激酶1/E3泛素蛋白连接酶通路及细胞凋亡的影响。方法:采用随机数字表法将40只雄性SD大鼠分为正常组、高脂高糖组、糖尿病组、灵芝孢子干预组,每组10只:高脂高糖组、糖尿病组、灵芝孢子干预组给予高脂高糖饮食至实验结束;高脂高糖饮食1个月后,糖尿病组、灵芝孢子干预组腹腔注射链脲佐菌素30 mg/kg建立2型糖尿病模型;造模成功后,灵芝孢子干预组灌胃给予灵芝孢子300 mg/(kg·d),其余3组灌胃给予等量生理盐水,持续给药12周。给药结束后,检测大鼠精子数量和形态、睾丸组织形态结构、血清睾酮和睾丸组织氧化应激水平,免疫组化分析PTEN诱导激酶1、E3泛素蛋白连接酶、抗核孔蛋白表达,Western blotting检测睾丸组织中PTEN诱导激酶1、E3泛素蛋白连接酶、抗核孔蛋白、程序性死亡受体1、微管相关蛋白轻链3Ⅱ/Ⅰ、caspase3、剪切caspase3的蛋白表达。结果与结论:①与正常组和高脂高糖组相比,糖尿病组大鼠精子数量减少(P<0.01),精子畸形率增加(P<0.01),血清睾酮浓度降低(P<0.01);与糖尿病组相比,灵芝孢子干预组大鼠精子数量增加(P<0.05),畸形率降低(P<0.01),血清睾酮浓度升高(P<0.01);②与正常组和高脂高糖组相比,糖尿病组大鼠睾丸组织中丙二醛水平升高(P<0.01),谷胱甘肽还氧化物酶和超氧化物歧化酶水平降低(P<0.01);与糖尿病组相比,灵芝孢子干预组大鼠睾丸组织中丙二醛水平降低(P<0.01),谷胱甘肽还氧化物酶和超氧化物歧化酶水平升高(P<0.01);③免疫组化染色显示,与正常组和高脂高糖组对比,糖尿病组大鼠睾丸组织中PTEN诱导激酶1、E3泛素蛋白连接酶阳性表达减少,抗核孔蛋白阳性表达增加;与糖尿病组相比,灵芝孢子干预组大鼠睾丸组织中PTEN诱导激酶1、E3泛素蛋白连接酶阳性表达增加,抗核孔蛋白阳性表达减少;④Western blotting检测显示,与正常组和高脂高糖组相比,糖尿病组PTEN诱导激酶1、E3泛素蛋白连接酶、程序性死亡受体1蛋白表达及微管相关蛋白轻链3Ⅱ/Ⅰ蛋白比值降低(P<0.05或P<0.01),抗核孔蛋白、caspase3、剪切caspase3的蛋白表达升高(P<0.01);与糖尿病组相比,灵芝孢子干预组PTEN诱导激酶1、E3泛素蛋白连接酶、程序性死亡受体1蛋白表达及微管相关蛋白轻链3Ⅱ/Ⅰ蛋白比值升高(P<0.05或P<0.01),抗核孔蛋白、caspase3、剪切caspase3的蛋白表达降低(P<0.05或P<0.01);⑤结果显示,灵芝孢子可能通过激活PTEN诱导激酶1/E3泛素蛋白连接酶信号通路增强睾丸组织自噬水平,减少组织细胞的凋亡,以此保护睾丸组织。

BACKGROUND:As a common complication of diabetes mellitus,male reproductive disorders have received increasing attention in recent years.Ganoderma spore have hypoglycemic,antioxidant and anti-inflammatory effects,but the regulatory mechanism for diabetic testicular tissue has not been fully elucidated.OBJECTIVE:To investigate the effect of ganoderma spore on the PTEN-induced kinase 1/E3 ubiquitin ligase pathway and cell apoptosis in testicular tissue of diabetic rats.METHODS:Forty male Sprague-Dawley rats were randomly divided into normal group,high fat and high sugar group,diabetic group and ganoderma spore group,with 10 rats in each group.The latter three groups were given high fat/high sugar diet until the end of the experiment.After 1 month of high fat/high sugar diet,the diabetic and ganoderma spore groups were given intraperitoneal injection of streptozotocin(30 mg/kg per day)to establish type 2 diabetic rat models.After successful modeling,the ganoderma spore group was intragastrically given ganoderma spore(300 mg/kg per day),and the other groups were given the same amount of normal saline for continuous 12 weeks.The sperm number and morphology were detected.The histopathological changes of the testicle were observed.Serum testosterone and oxidative stress levels in testicular tissue were measured.The levels of PTEN-induced kinase 1,E3 ubiquitin ligase,and anti-nucleoporin p62 were analyzed by immunohistochemistry and the expression of PTEN-induced kinase 1,E3 ubiquitin ligase,anti-nucleoporin p62,programmed cell death-1,microtubule-associated protein light chain 3 II/I,caspase 3,cleaved-caspase 3 were detected by western blot assay.RESULTS AND CONCLUSION:Compared with the normal group and the high fat and high sugar group,the diabetic group had decreased sperm number(P<0.01),increased sperm malformation rate(P<0.01),and decreased serum testosterone level(P<0.01).Compared with the diabetic group,ganoderma spore intervention could increase the sperm number(P<0.05),decrease the malformation rate(P<0.01),and increase the serum testosterone level(P<0.01).Compared with the normal group and the high fat and high sugar group,the malondialdehyde level in testis tissue was increased in the diabetic group(P<0.01),while the levels of glutathione deoxidase and superoxide dismutase decreased(P<0.01).Compared with the diabetic group,the malondialdehyde level in testis tissue was decreased in the ganoderma spore group(P<0.01),and the levels of glutathione deoxidase and superoxide dismutase increased(P<0.01).Immunohistochemical staining showed that compared with the normal group and the high fat and high sugar group,the positive expressions of PTENinduced kinase 1 and E3 ubiquitin ligase in testicular tissue were decreased in the diabetic group,while the positive expressions of anti-nucleoporin p62 were increased.Compared with the diabetic group,the positive expressions of PTEN-induced kinase 1 and E3 ubiquitin ligase in testicular tissue e were increased in the ganoderma spore group,while the positive expression of anti-nucleoporin p62 was decreased.Western blot assay results indicated that compared to the normal group and the high fat and high sugar group,the expression of PTEN-induced kinase 1 and E3 ubiquitin ligase,programmed cell death-1 and the ratio of microtubule-associated protein light chain 3 II/I protein were decreased in the diabetic group(P<0.05 or P<0.01),while the expressions of anti-nucleoporin p62,caspase3 and cleaved-caspase3 were increased(P<0.01).Compared with the diabetic group,ganoderma spore intervention could elevate the expression of PTEN-induced kinase 1 and E3 ubiquitin ligase,programmed cell death-1 and the ratio of microtubule-associated protein light chain 3 II/I protein(P<0.05 or P<0.01)as well as reduce the expressions of anti-nucleoporin p62,caspase3 and cleaved-caspase3(P<0.05 or P<0.01).Overall,ganoderma spores may activate the PTEN-induced kinase 1/E3 ubiquitin ligase pathway to enhance autophagy in testicular tissue and reduce apoptosis in tissue cells,so as to protect testicular tissue.