Effect of Stevia rebaudiana Bertoni aqueous extract on steroid-induced cataract in chick embryo model

Abstract

Stevia has been used for years as a traditional remedy and sweetener, but its effect on the eye has not been adequately studied. In this study, we aimed to investigate the effect of Stevia rebaudiana Bertoni aqueous extract (SAE) on steroid-induced cataract in a chicken embryo model. The phytochemical profile was determined by LCMS/MS. Eggs were treated with SAE (100, 200, and 400 mg/kg) 3 h after injection of hydrocortisone sodium succinate (HC) (0.50 mu mol/100 mu l into the air sac) on day 15. On day 17, lens opacity was assessed. TAS, TOS, GSH, MDA, TUNEL index, caspase-3, and proliferating cell nuclear antigen (PCNA) H -score were determined in the lenses. AlphaA-crystallin (CRYAA) gene expression was also determined using RT-PCR. SAE had high levels of antioxidant compounds such as chlorogenic acid (21.372 mg/g), quinic acid (8.306 mg/g) and quercitrin (6.291 mg/g). While the mean cataract grade in the HC group was 4.25, it was determined to be 3.6, 2.6, and 3, respectively, in the low-to-high dose treatment group. SAE effectively attenuated HC-induced cataract by reducing oxidative stress (increase in TAS and GSH, decrease in TOS and MDA). Histopathologic results confirmed the effect of SAE by decreasing TUNEL and caspase-3 expressions and increasing PCNA expression. In addition, CRYAA gene expression levels increased from the low to the high dose in the treatment groups (1.656fold, 1.369-fold, and 2.010-fold, respectively). The results of the current study provide strong mechanistic evidence for the therapeutic/protective effect of SAE (200-400 mg/kg) against HC-induced cataract formation in chick embryos.