摘要
背景糖尿病可以诱发视网膜细胞凋亡并下调视网膜内源性降钙素基因相关肽（CGRP）表达，辣椒素可引起CGRP等感觉神经递质释放并且参与器官保护，然而CGRP在糖尿病视网膜病变（DR）细胞凋亡中的作用如何尚待进一步阐明。目的观察辣椒素预处理对链脲佐菌素（STZ）诱发的DR视网膜细胞凋亡的影响以及视网膜和血清CGRP表达的变化。方法将40只健康成年雄性sD大鼠按随机数字表法随机分为DR模型组、药物干预组、药物对照组、DR对照组和空白对照组，每组8只。DR模型组大鼠腹腔内注射质量分数1％STZ溶液（60mg／kg）1．2ml制作DR模型；DR对照组大鼠腹腔内注射0．1mol／L、pH4．5的柠檬酸缓冲液1．2ml；药物干预组大鼠造模前3d皮下注射质量分数1％辣椒素溶液（20mg／kg）0．4ml，第4天腹腔注射STZ溶液；药物干预对照组大鼠造模前3d皮下注射1％辣椒素溶液（20mg／kg）0．4ml，第4天腹腔注射0．1mol／L、pH4．5的柠檬酸缓冲液1．2ml；空白对照组不做任何处理。造模成功后饲养10周，采用TUNEL法染色和半胱氨酸天冬蛋白酶3（caspase-3）活性检测法分别检测各组大鼠视网膜细胞凋亡程度，同时采用酶联免疫吸附法（ELISA）检测各组视网膜和血清中CGRP的表达。结果DR模型组大鼠视网膜神经节细胞（RGCs）层凋亡率为（43．4±5．0）％，明显高于药物干预组的（30．0±5．1）％，差异有统计学意义（t=5．930，P〈0．01）；DR对照组和药物对照组大鼠RGCs凋亡率分别为（12．4±9．9）％和（17．6±6．1）％，与各自的DR组比较，差异均有统计学意义（t=8．800、4．925，P〈0．01）。空白对照组大鼠RGCs凋亡率为（16．2±6．9）％，与DR对照组和药物对照组比较，差异均无统计学意义（t=-0．989、0．951，P〉0．05）。DR模型组大鼠视网膜中caspase-3比活性值为2．19±0．86，药物干预组为1．96±O．56，差异有统计学意义（t=-0．515，P〈0．05），而DR对照组和药物对照组大鼠视网膜caspase-3的活性比值分别为1．47±0．14和0．74±0．27，与各自的实验组比较，差异均有统计学意义（t=2．142、2．797，P〈0．05）。DR模型组视网膜和血清中CGRP质量浓度分别为（424．4±44．2）ng／L和（148．8±39．1）ng／L，明显低于药物干预组的（543．2±74．4）ng／L和（237．5±78．7）ng／L，差异均有统计学意义（t=3．070、2．359，P〈0．05）。结论DR可引起RGCs凋亡，小剂量辣椒素可减少凋亡细胞数量，并诱导视网膜组织和血液内CGRP水平上调，提示CGRP对DR引起的RGCs凋亡可能有保护作用。
Background Diabetes mellitus （DM） can provoke the apoptosis of retinal cells and down- regulate the expression of calcitonin gene related peptide （CGRP） in the retina. Capsaiein promotes the release of CGRP and elicits protective effects on human organs. However, whether CGRP protects retinal cells in diabetic retinopathy （DR） is still unclear. Objective The study was designed to examine the effect of eapsaicin on the apoptosis of retinal cells in diabetic rats and its relationship with CGRP. Methods Forty clean healthy adult male Sprague-Dawey rats were randomly divided into the diabetes group, capsaicin pretreated group, streptozocin （STZ） control group, capsaicin control group and plain control group, with 8 rats per group. The diabetic model was established by the intraperitoneal injection of 60 mg/kg in all rats except those of the plain control group. 0.4 mL of a 1% capsaicin injected at 20 mg/kg was subcutaneously injected for 3 consecutive days prior to model establishment in the capsaicin pretreated group,after which 1.2 mL of STZ was intraperitoneally injected on the fourth day. Rats from the STZ control group were administered intraperitoneally 1.2 mL of 0. 1 tool/L, pH 4.5 ,citrate buffer. The capsaicin control group received subcutaneous injections of 0.4 mL of 1% capsaicin at 20 mg/kg for 3 consecutive days, after which 1.2 mL of 0. 1 mol/L, pH 4.5 ,eitrate buffer was administered intraperitoneally. The rats were sacrificed at the tenth week after model establishment and retinal specimens were prepared for the apoptosis assay by TUNEL staining and the quantitative analysis of caspase-3 activity. Expression of CGRP in the retina and serum was detected using ELISA. The use of experimental animals followed the Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission. Results Retinal cell apoptosis was mainly localized to the retinal ganglion cell （RGC） layer. The apoptosis rate of RGCs was （43.4±5.0）% in the DR model group and （30.0±5. 1 ）% in the capsaicin pretreated group,showing a significant difference （t=5. 930,P〈0.01 ）. Compared with the DR model group and capsaicin pretreated group,the apoptosis rates of the DR control group （12.4 ±9. 9） % and the capsaicin control group （ 17.6±6. 1 ） % The apoptosis rate of the plain control group was （ 16.2±6 were significantly lower （t = 8. 800, t = 4. 925, P〈0. 01 ）. 9） % , exhibiting significant differences in comparison with the DR control group and capsaicin control group （ t = -0. 989, t = 0.951, P〉0.05 ）. The specific activity of caspase-3 was （2. 19±0.86） in the DR model group and （1.96±0.56） in the capsaicin pretreated group, presenting a significant difference （t=-0. 515 ,P〈0.05 ）. Those of the DR control group and capsaicin control group were （1.47± 0. 14） and （0.74 ±0.27）, respectively, with considerable decline in comparison with the DR model group and capsaicin pretreated group （t = 2. 142 ,t= 2. 797 ,P〈0.05 ）. The retinal and serum CGRP levels were （424.4±44.2） and （ 148. 8±39. 1 ） ng/L,respectively, displaying significantly lower levels than （543.2±74.4） and （237.5±78.7） ng/L （t = 3. 070,2. 359 ,P〈0.05 ） from the capsaicin pretreated group. Conclusions Apoptosis of retinal ganglion cells occurs in the STZ-induced diabetic rats. Pretreatment of capsaicin reduces retinal cell apoptosis, which may be associated with an increase of CGRP in the retina.
出处
《中华实验眼科杂志》
CAS
CSCD
北大核心
2013年第1期34-38,共5页
Chinese Journal Of Experimental Ophthalmology
基金
国家自然科学基金项目（30772083）
山西省科技攻关项目（2007031096-2）
