藏红花素对视网膜缺血再灌注损伤大鼠视网膜组织结构及肿瘤坏死因子-α、白细胞介素-1β表达的影响

目的观察藏红花素对视网膜缺血再灌注损伤（RIR）大鼠视网膜组织结构及肿瘤坏死因子-α（TNF-α）、白细胞介素-1β （IL-1β ）表达的影响。方法采用随机数字表法将80只8～10周龄健康无眼疾Sprague—Dawley（SD）雄性大鼠随机分为正常对照组、模型组、藏红花素低剂量组和藏红花素高剂量组，每组20只。正常对照组大鼠不作任何处理。其余组采用前房灌注生理盐水升高眼内压法建立RIR模型。藏红花素低剂量组、藏红花素高剂量组均于建模前30min和建模后每天定时分别以5mg／kg、50mg／kg的剂量腹腔注射藏红花素溶液。建模后6、12、24、48h，作视网膜石蜡切片行苏木精-α红染色，光学显微镜观察各组大鼠视网膜组织结构；作视网膜组织匀浆，采用酶联免疫吸附试验测定各组TNF-α、IL-1β 的表达。结果光学显微镜观察发现，正常对照组大鼠视网膜组织结构正常；模型组大鼠出现视网膜水肿、结构紊乱、细胞排列疏松等病理改变；藏红花素低剂量组大鼠视网膜病理改变程度较模型组轻；藏红花素高剂量组大鼠视网膜组织结构与正常对照组相似。TNF-α在建模后24h表达量最高，IL-1β 在建模后12、48h时表达量最高。建模后6、12、24、48h，模型组（t=5．42、7．94、9．32、9．18）、藏红花素低剂量组（t=3．94、4．12、4．98、3．84）TNF-α表达均较正常对照组升高，差异有统计学意义（P〈0．05）；藏红花素高剂量组TNF-α表达较正常对照组有所升高，但差异无统计学意义（t=2．13、2．34、2．96、2．78，P〉0．05）。与模型组比较，藏红花素低剂量组（t=3．95、4．56、4．01、5．12）、藏红花素高剂量组（t=5．23、7．65、7．74、7．63）TNF-α表达均降低，差异有统计学意义（P％0．05）。建模后6、12、24、48h，模型组（t=7．23、7．87、7．15、15．60）、藏红花素低剂量组（t：5．65、5．10、5．54、6．87）、藏红花素高剂量组（t=4．38、5．21、4．56、4．75）IL-1β表达均较正常对照组升高，差异有统计学意义（P〈0．05）。与模型组比较，藏红花素低剂量组仅于建模后48h降低最为明显，差异有统计学意义（t=7．56，P％0．05）；各时间点藏红花素高剂量组IL-1β表达均降低，差异均有统计学意义（t=6．94、5．36、6．05、10．50，P〈0．05）。结论藏红花素可以改善RIR大鼠视网膜组织结构的病理改变，降低TNF-α、IL-1β的表达。

Objective To observe the effect of Crocin on structure and the expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in rat retina after injury by ischemia-reperfusion.Methods A total of 80 Sprague-Dawley male rats at the age of 8-10 weeks were divided into control group,model group,low-dose Crocin group and high-dose Crocin group,with 20 rats in each group.The rats of control group were not treated.The rats in model,low-dose Crocin and high-dose Crocin group were induced with normal saline by anterior chamber perfusion creating a retinal ischemia-reperfusion (RIR) model.The rats of the low-dose Crocin and high-dose Crocin group received intraperitoneal injection with different doses of Crocin solution (5 mg/kg,or 50 mg/kg) 30 minutes prior to ischemic injury and one time per day after successful RIR.Optical microscopy was used to observe the retinal structure.Enzyme-linked immunosorbent assay (ELISA) was used to measure the expression of TNF-α and IL-1β 6,12,24 and 48 hours after RIR.Results The retinal structure of control group was normal.Pathological changes were found in the RIR model and low-dose Crocin group,such as retinal edema,disorganized structure and loosely packed cells.The degree of pathological changes in low dose Crocin group was less than the RIR model group.The retinal structure of high-dose Crocin group was similar to the control group.The expression of TNF-α was the highest at 24 hours after modeling,while the expression of IL-1β was the highest at 12 and 48 hours after RIR modeling.Six,12,24 and 48 hours after RIR modeling,compared with the control group,the TNF-α expression of model (t=5.42,7.94,9.32,9.18; P＜0.05),low-dose Crocin (t=3.94,4.12,4.98,3.84; P＜0.05) and high-dose Crocin group (t=2.13,2.34,2.96,2.78;P＞0.05) were increased.Compared with the RIR model group,the TNF-α expression of low-dose Crocin (t=3.95,4.56,4.01,5.12) and high-dose Crocin group (t =5.23,7.65,7.74,7.63) was decreased.Compared with the control group,the IL-1β expression of model (t=7.23,7.87,7.15,15.60),low-dose Crocin (t 5.65,5.10,5.54,6.87;P＜0.05) and high-dose Crocin group (t=4.38,5.21,4.56,4.75) was increased (P＜0.05).Compared with the model group,the IL-1β expression of low-dose Crocin group was decreased significantly 48 hours after RIR modeling (t=7.56,P＜0.05) ; but it decreased significantly at each time point in high-dose Crocin group (t=6.94,5.36,6.05,10.50; P＜0.05).Conclusion Crocin can improve the retinal pathologic changes,while down regulating TNF-α and IL-1β expression in RIR rats.