Objective To investigate protective effect of tribulus terrestris L (TTL) on photoreceptor in the model of light-induced retinal degeneration.Methods BALB/c mice were exposed to bright light at the intensity of 10 000 lux for 30 minutes to establish the retinal light damage models.The BALB/c mice were divided into normal control group,model group and treatment group,6 cases in each group.TTL decoction was intraperitoneally administered to mice 30 minutes prior to illumination in the treatment group.Saline vehicle was administered in the normal control group and model group.Photoreceptor protection of TTL was assessed by optical coherence tomography (OCT) at 3 hours and 7 days after illumination.Gross histology and immunohistochemistry approaches were also taken to examine the retinal protection conferred by TTL at 7 days after bright light exposure.Results Compared to normal retinal morphology in the normal control group,prominent photoreceptor loss and diminished rod and cone photoreceptors evidenced by attenuated retinal expression of rhodopsin and M-opsin were observed in the model group.In contrast,TTL treatment resulted in significant protection against bright light-induced photoreceptor degeneration and remarkable preservation of rod and cone photoreceptor cells.The outer retinal nuclear layer in the model group was thinner than that in the normal control group (P ＜ 0.05),but the treatment group was thicker than the model group (P ＜ 0.05).Conclusion Bright light induces obviously degeneration in photoreceptors in BALB/c mice.Moreover,TTL is shown for the first to significantly protect the photoreceptors from bright light-induced degeneration.