生姜提取物对链脲佐菌素诱导的糖尿病大鼠晶状体的保护作用

摘要

目的 探讨生姜提取物对链脲佐菌素(streptozotocin,STZ)诱导的糖尿病大鼠晶状体的保护作用.方法 60只SD大鼠随机分为A组(正常对照组)、B组(糖尿病组)、C1组(糖尿病+生姜灌胃50 mg·kg-1组)、C2组(糖尿病+生姜灌胃100mg· kg-1组)、C3组(糖尿病+生姜灌胃300 mg·kg-1组),每组各12只.除A组腹腔注射等体积生理盐水外,其余各组均一次性腹腔注射STZ 65 mg· kg-1.动物模型建立成功后,立即予以C1、C2、C3组大鼠生姜提取物灌胃,A、B组给予等量生理盐水灌胃.观察大鼠成模前与成模后4周、8周、12周时血糖、晶状体变化情况.成模后4周、8周、12周分批处死大鼠并立即取出晶状体,ELISA检测晶状体醛糖还原酶(aldose reductase,AR)含量;Western blot检测糖基化终末产物(glycosylation end products,AGEs)的表达;超氧化物歧化酶(superoxide dismutase,SOD)活性测定试剂盒检测SOD活性,丙二醛(malondialdehyde,MDA)含量测定试剂盒检测MDA含量;TUNEL法检测晶状体上皮细胞(lens epithelial cells,LECs)凋亡率,扫描电镜观察晶状体超微结构变化.结果 糖尿病大鼠晶状体SOD活性呈下降趋势,差异均有统计学意义(均为P＜0.05).除A、C3组外,其余各组大鼠晶状体MDA含量变化在成模后4周、8周、12周时差异均有统计学意义(P =0.003、0.000、0.017).B组大鼠AR持续性增高(P =0.003).C1、C2、C3组大鼠晶状体AR含量呈下降趋势,差异均有统计学意义(P =0.007、0.000、0.000).C1、C2、C3组大鼠晶状体AGEs表达情况差异均有统计学意义(均为P＜0.05).扫描电镜发现,B组大鼠晶状体皮质纤维破坏程度呈进行性加重,C1、C2、C3组大鼠皮质破坏程度随灌胃浓度的增加而呈减轻趋势.A组大鼠LECs凋亡率无明显差异性变化(P=0.191),其余大鼠LECs的凋亡呈现上升趋势,差异均有统计学意义(均为P＜0.05).结论 生姜提取物灌胃可延迟糖尿病大鼠晶状体混浊时间并减慢其进展速度,并有一定的浓度依赖性,这可能是通过抑制醛糖还原酶活性、氧化应激反应、AGEs的产生以及晶状体上皮细胞凋亡等途径实现的.%Objective To observe the protective mechanisms of zingiber officinalis extract on the lens of diabetic rats induced by streptozotocin (STZ).Methods Totally 60 SD rats were randomly divided into A group (normal control rats),B group (diabetic rats),C1 group (DM +50 mg · kg-1 ginger gavage),C2 group (DM + 100 mg ·kg-1 ginger gavage) and C3 group (DM + 300 mg · kg-1 ginger gavage).Each group had 12 rats.And rats in A group received intraperitoneal injection of the same volume of normal saline,while the other groups were intraperitoneally injected with 65 mg · kg-1streptozotocin (STZ).When the animal model was successfully established,both A group and B group were administered orally with normal saline,and the C1,C2 and C3 groups were administered orally with ginger rhizome extract.The changes in blood glucose and lens were observed every week.The rats were sacrificed in succession at 4 week,8 week,12 week,and the lens was removed immediately.The content of aldose reductase (AR) was detected by ELISA,and the expression of glycosylation end products (AGEs) was detected by Western blot.The superoxide dismutase (SOS) activity and malondialdehyde (MDA) content were also detected.Fluorescent Tunel staining was used to detect the apoptosis of the lens epithelial cells.And finally,scanning electron microscopy was used to observe the ultrastructural changes in the lens.Results The activity of SOD in the lens of diabetic rats showed a decreasing trend with statistical significance (all P ＜ 0.05).Changes in the content of MDA in the lens of rats in B,C1,C2 group were statistically significant in 4,8 and 12 weeks after successful modeling (all P ＜ 0.05),but no significant difference in A group and C3 group (both P ＞ 0.05).The persistent increase of AR in group B (P =0.003).The content of AR of the lens in C1,C2,C3 group showed a decreasing trend,and the differences were statistically significant (all P ＜ 0.05).There were significant differences in the expression of AGEs in C1,C2 and C3 group (all P ＜ 0.05).The degree of cortical fiber destruction in group B was progressively aggravated,but the degree of cortical destruction in C1,C2 and C3 group decreased with the increase of ginger gavage concentration through the scanning electron microscopy.It was observed that there was no significant difference in the apoptotic rate of LECs in A group (P =0.191),but the apoptosis of LECs in the rest group showed a rising trend,and the differences were statistically significant (all P ＜ 0.05).Conclusion The effects of ginger gavage extract can delay the opacification of lens and slow down the diabetic development in rats with a dose-independence manner.Ginger gavage extract may play a protective role on the lens of diabetic rats by inhibiting the activity of AR,oxidative stress and the production of AGEs as well as suppress the apoptosis of lens epithelial cells.