Aim: To evaluate the effect of tetramethylpyrazine (TMP) injection on retinal damage induced by N-methyl-N-nitrosourea (MNU) in rats and on nuclear factorkappa B (NF-κB) family members.Methods: Female Sprague-Dawley (SD) rats were randomly divided into groups: (i), control group; (ii), model group; and (iii),TMP-injection groups, in which the rats were subdivided into 40 mg/kg, 80 mg/kg and 160 mg/kg groups.Drugs were injected ip into 47-day-old SD rats once a day.physiological saline.All rats were killed at different times after MNU or physiological saline treatment.The apoptotic index of photoreceptor cells was calculated by TUNEL labeling; retinal damage was evaluated based on retinal thickness and the expression of NF-κB family members was detected by Weste blot.Results: TMP injections, in a dose-dependent manner, suppressed photoreceptor cell apoptosis and decreased its loss in the peripheral retina.As compared with the MNU-treated group, TMP injection at a dose of 160 mg/kg also timedependently upregulated the NF-κB/p65 protein level in the nucleus and downregulated the Iκ Bα protein level in the cytoplasm.However, no protective effect of TMP injection on MNU-induced central retinal damage was found.Conclusion: TMP injection partially protects against MNU-induced retiral damage by upregulating the nuclear translocation of p65 to inhibit photoreceptor cells apoptosis.