Investigation of chrysin's antioxidant effect in experimental cataract model created in chick embryos

Cataract, which is the result of opacification of the lens, is one of the most common causes of vision loss. In the literature, deterioration of the antioxidant system due to the increase in reactive oxygen species and oxidant levels is shown among the causes of cataract formation. One of the complications of long-term steroid use is the formation of cataracts. Chrysin, a natural flavonoid, has various properties such as antioxidant, anti-inflammatory and anticancer. Considering these data, the aim of our study is to determine the antioxidant effect of chrysin in a steroid-induced cataract formation in experimental chick embryo model. Within the scope of the study, 150 specific pathogen free (SPF) fertilized eggs were used. Eggs divided into 6 groups as control group, corn oil group, HC group, low (0.1 ml HC and 25 mg/kg chrysin), medium (0.1 ml HC and 50 mg/kg chrysin) and high dose (0.1 ml HC and 100 mg/kg chrysin) chrysin. Chrysin and HC applications were made in to the air sac using an insulin injector on the 15th day of incubation. On day 17, all chick embryos were removed from the eggs and the bulbus oculi of the embryos were dissected. In each group; 9 embryos for cataract grading, 8 embryos for biochemical analysis of glutathione (GSH), malondialdehyde (MDA), total antioxidant level (TAS), total oxidant level (TOS), caspase 3 and caspase 9 levels, and 7 embryo for histological evaluation (TUNEL method) was used. Opacity was not observed in any lens in the control group. In the HC group only, cataracts were detected in all of the lenses, and the mean cataract grade was calculated as 3.5. The mean opacity grades were determined as 3.1, 2.3 and 1.5 in the HC+chrysin groups from low dose to high dose, respectively, and the difference between high dose chrysin group and HC group was statistically significant (p<0.05). GSH and TAS levels, which statistically decreased significantly (p<0.05) in the lenses compared to the control group due to HC application, increased in direct proportion to the application dose of chrysin (p<0.05). The increased levels of MDA, TOS, caspase 3 and caspase 9 in the HC group decreased significantly inversely with the chrysin dose (p<0.05). In addition, when the rate of apoptotic cells determined by the TUNEL method was compared between the groups; while it was statistically significantly higher in the HC administered group than in the control group (p<0.05), it was statistically significantly decreased in chrysin groups, inversely proportional to the dose rate (p<0.05). These findings are important in terms of demonstrating chrysin as a potential antioxidant agent that prevents cataract formation. We consider that our study may serve as a reference for similar studies to be conduded in future.