[Effects of Danqi Huayu Recipe on retinal cell apoptosis in rat model of light-induced retinal damage].

This study aims to explore the protective mechanism of Danqi Huayu Recipe against light-induced retinal damage(LIRD) in rats from the perspective of cell apoptosis. Sixty male SD rats were randomly allocated into six groups(n=10): normal group, model group, Ziyin Mingmu Pills group(7.8 g·kg~(-1)), and low-, medium-, and high-dose(3.45, 10.35, and 31.05 g·kg~(-1), respectively) Danqi Huayu Recipe groups. A self-made light damage chamber was used for the modeling of LIRD in rats of other groups except normal group. Seven days after modeling, each group received corresponding agents by gavage. Normal group and model group were administrated with an equal volume of distilled water by gavage for 14 d. The retinal function was evaluated by electroretinography. Hematoxylin-eosin(HE) staining was employed to observe the retinal morphology and measure the thickness of the outer nuclear layer(ONL). The cell apoptosis was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling. The ultrastructure of the retina was observed by transmission electron microscopy. The protein and mRNA levels of factors related to retinal cell apoptosis were determined by Western blot and RT-qPCR, respectively. The results showed that compared with normal group, model group demonstrated significantly decreased amplitudes of ERG a-waves and b-waves, thinned ONL, increased cell apoptosis rate, damaged retinal ultrastructure, down-regulated protein and mRNA levels of the anti-apoptotic factor(Bcl-2), and up-regulated protein and mRNA levels of pro-apoptotic factors(Caspase-3, Caspase-6, p53, and Bax). Compared with model group, Ziyin Mingmu Pills group and medium-and high-dose Danqi Huayu Recipe group recovered the amplitudes of ERG a-waves and b-waves, increased the ONL thickness, decreased the cell apoptosis rate, and improved the retinal ultrastructure. Meanwhile, they up-regulated protein and mRNA levels of Bcl-2 and down-regulated protein and mRNA levels of pro-apoptotic factors in a dose-dependent manner. In conclusion, Danqi Huayu Recipe protects rats from LIRD by regulating the expression of proteins and genes related to cell apoptosis to reduce light-induced retinal cell apoptosis.