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本研究观察葛根素是否减轻部分由过氧亚硝基阴离子(peroxynitrite,ONOO–)导致的糖尿病大鼠晶状体上皮细胞(lensepitheliumcell,LEC)凋亡。采用大鼠腹腔注射链脲佐菌素(streptozotocin,STZ)的方法建立糖尿病动物模型。36只大鼠作为对照组,腹腔注射生理盐水;其他72只大鼠腹腔注射STZ(45mg/kg)后分为STZ组和STZ+葛根素组,每组36只。STZ注射3d后,STZ+葛根素组大鼠每天腹腔注射葛根素(140mg/kg)。于实验开始后第20、40和60天用裂隙灯检查晶状体的形态学变化后处死动物。用流式细胞仪检测LEC凋亡,用免疫组化方法检测晶状体中ONOO–的标志物——硝基酪氨酸(nitrotyrosine,NT)的表达,用基因芯片分析技术检测LEC凋亡相关基因iNOS等的表达。结果发现,对照组大鼠晶状体均透明,各项指标基本正常;STZ组大鼠第20天时即出现晶状体混浊,40~60d期间混浊不断加重;STZ+葛根素组大鼠20~40d时晶状体混浊呈加重趋势,但40~60d以后明显减轻。对照组LEC轻度凋亡,而STZ组凋亡细胞呈持续性增长,STZ+葛根素组大鼠20~40d时细胞凋亡呈增长趋势,但40~60d以后明显下降。对照组大鼠晶状体NT未见明显表达;STZ组大鼠NT表达明显加强;STZ+葛根素组大鼠20~40d时NT表达呈增长趋势,但40~60d以后明显下降。对照组凋亡相关基因未见明显变化,STZ组凋亡相关基因iNOS表达明显上调。其他凋亡相关基因如BCL-2、SOD表达明显下调,但NF-κB和TNFR1-FADD-caspase信号转导途径明显上调;STZ+葛根素组凋亡相关基因表达则呈相反改变。上述结果表明,在糖尿病大鼠晶状体中有ONOO–的标志物NT表达,证明糖尿病大鼠LEC凋亡部分由ONOO–诱导,这可能是氧化损伤导致白内障形成的新途径。葛根素能够部分逆转ONOO–对LEC的致凋亡作用,提示葛根素可能是治疗糖尿病性白内障的有效药物,其治疗机制可能与葛根素直接抑制凋亡和对抗ONOO–对糖尿病大鼠LEC的损伤有关。
This study was to observe whether puerarin alleviated apoptosis of lens epithelial cells (LEC) in diabetic rats partially caused by peroxynitrite (ONOO–). The rat model of diabetes was established by intraperitoneal injection of streptozotocin (STZ). Thirty-six rats were used as control group and intraperitoneal injection of physiological saline. The other 72 rats were intraperitoneally injected with STZ (45 mg/kg) and divided into STZ group and STZ+Puerarin group, 36 rats in each group. After STZ injection for 3 days, rats in STZ + puerarin group were given intraperitoneal injection of puerarin (140 mg/kg) daily. At 20, 40 and 60 days after the start of the experiment, the animals were sacrificed after examining the morphological changes of the lens with a slit lamp. LEC apoptosis was detected by flow cytometry, and the expression of nitrotyrosine (NT) was detected by immunohistochemistry. The microarray analysis was used to detect the apoptosis-related gene iNOS in LECs. Expressions such as. The results showed that the lens of the control group was transparent and the indexes were basically normal; the lens of the STZ group appeared turbid on the 20th day, and the turbidity continued to increase during the 40th to 60th days; the lens turbidity of the STZ+puerarin group rats was 20-40 days. Aggravating trend, but significantly reduced after 40 ~ 60d. In the control group, LECs were slightly apoptotic, while the apoptotic cells in STZ group continued to increase. The apoptosis of STZ+puerarin group increased from 20 to 40 days, but decreased significantly after 40 to 60 days. There was no obvious expression of NT in lens of control group; NT expression in STZ group was significantly increased; NT expression in STZ+puerarin group showed an increasing trend from 20 to 40 days, but decreased obviously after 40 to 60 days. There was no significant change in the apoptosis-related genes in the control group, and the expression of iNOS was significantly up-regulated in the STZ group. Other apoptosis-related genes such as BCL-2 and SOD were significantly down-regulated, but NF-κB and TNFR1-FADD-caspase signal transduction pathways were significantly up-regulated. The expression of apoptosis-related genes in STZ+puerarin group was reversed. The above results indicate that there is NT expression of the ONOO–marker in the lens of diabetic rats, which proves that the apoptosis of LEC in diabetic rats is partially induced by ONOO–, which may be a new way for oxidative damage to cause cataract formation. Puerarin can partially reverse the ONOO--induced apoptosis of LEC, suggesting that puerarin may be an effective drug for the treatment of diabetic cataract. Its therapeutic mechanism may be that puerarin directly inhibits apoptosis and fights against ONOO--an injury to LEC in diabetic rats. related.