白蒺藜对光感受器细胞的抗炎、抗氧化保护效应机制研究

Tribulus terrestris L protects the photoreceptors against light-induced degeneration in part through suppression of retinal inflammation and oxidative stress

目的探讨白蒺藜对光损伤诱导的光感受器细胞退行性改变的保护作用。方法 36只小鼠随机分为3组,每组各12只,采用10×10~3 Lux白炽光光照30 min建立BALB/C小鼠视网膜光损伤模型,光照前30 min白蒺藜给药组腹腔注射白蒺藜水煎液100μL,正常对照组和光损伤模型组腹腔注射等量生理盐水。光照后22 h,腹腔注射二氢乙锭,2 h后摘取眼球制备冰冻切片,观察视网膜原位氧化应激状态。分别于光照后6h、24 h摘取视网膜组织,进行总RNA抽提、逆转录制备cDNA样品,通过实时荧光定量PCR分析小鼠视网膜炎症相关因子。检测白细胞介素-1β(interleukin-1β,IL-1β)、趋化因子CcL2(chemokine,Ccl2)、环氧合酶-2(cyclooxygenase-2,COX-2)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、细胞间黏附因子-1(intercellular cell adhesion molecules-1,ICAM-1)、血管细胞黏附分子-1(vascular cell adhesion molecule-1,VCAM-1)基因的mRNA表达水平。结果光照24 h后,与正常对照组、白蒺藜给药组相比较,光损伤模型组视网膜色素上皮细胞及光感受器细胞氧化应激标志物呈显著阳性,差异均有统计学意义(均为P<0.001)。与正常对照组相比较,光损伤模型组视网膜IL-1β、Ccl2、COX-2、TNF-α、ICAM-1、VCAM-1的mRNA表达水平显著升高,差异均具有统计学意义(均为P<0.01);与光损伤模型组相比,白蒺藜给药组视网膜IL-1β、Ccl2、COX-2、TNF-α、ICAM-1、VCAM-1的mRNA表达水平显著降低,差异均有统计学意义(均为P<0.01)。结论在视网膜退行性病变模型中,白蒺藜表现出良好的光感受器细胞保护作用。抗氧化、抗炎可能是白蒺藜防治光感受器细胞损伤效应的相关机制之一。

Objective To investigate the protective effects of tribulus terrestris L(TTL)against light-induced photoreceptor degeneration and its underlying mechanisms.Methods BALB/c mice were randomly divided into normal control group,light exposure group and TTL administration group,with 12 mice in each group,and then exposed to light at the intensity of 10,000 lux for 30 min for the establishment of a retinal damage model of BALB/C mice.And 100μL TTL decoction was intraperitoneally administered into mice of TTL administration group 30 min prior to illumination.Saline vehicle was administrated into the mice of normal control group and light exposure group.Next,intraperitoneal injection of dihydroethidium(DHE)was performed 22 h after illumination,and the eyes were enucleated 2 h later and subjected to cryosectioning for microscopic detection of the in situ retinal oxidative stress.Then,retinas were dissected 6 and 24 h after illumination,which was followed by total RNA extraction,reverse transcription and RT-PCR to assess the expression level of proinflammatory cytokines.Meanwhile,the expression levels of interleukin-β(IL-1β),chemokine(Ccl2),cyclooxygenase-2(COX-2),tumor necrosis factor-α(TNF-α),cell adhesion molecule-1(ICAM-1)and vascular cell adhesion molecule-1(VCAM-1)mRNA were determined.Results Prominent oxidative stress was observed in retinal pigment epithelial cells and photoreceptor cells in the light exposure group when compared with the normal control group and TTL administration group,with significant difference(both P<0.001).Moreover,results of RT-PCR revealed that the expression of IL-1β,Ccl2,COX-2,TNF-α,ICAM-1 and VCAM-1 mRNA was significantly elevated as a result of light exposure compared to those from vehicle-treated normal controls with a significant difference(all P<0.01).TTL treatment resulted in significantly decreased expression of IL-1β,Ccl2,COX-2,TNF-α,ICAM-1 and VCAM-1 mRNA compared to those from light-exposed vehicle-treated controls with significant differences(all P<0.01).Conclusion In the retinal degeneration model,TTL protects the photoreceptor cells against light-induced degeneration in part through suppressing light-induced retinal oxidative stress and inflammatory responses.