RESUMO
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 100 μL 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-1 β),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 fight-induced degeneration in part through suppressing light-induced retinal oxidative stress and inflammatory responses.