İnvestigation of the effect of asiatic acid in an experimental cataract model

Cataract is an ocular disorder characterized by the loss of lens transparency and is one of the leading causes of reversible blindness worldwide. Oxidative stress is known to play a significant role in the development of cataracts. An increase in free radicals and insufficient antioxidant defense mechanisms disrupt the structural integrity of lens proteins, leading to the formation of opacities. Globally, the rapid increase in the elderly population—driven by socioeconomic development and improved access to healthcare—has led to a rise in the incidence of age-related cataract surgery, substantially increasing healthcare expenditures. The financial burden of surgery and the risk of complications have spurred research into strategies for cataract prevention or delay. Consequently, compounds with antioxidant properties have attracted attention for their potential to inhibit or slow the onset of cataracts. This study investigates the effects of asiatic acid (AA), a natural pentacyclic triterpenoid compound, on a sodium selenite-induced experimental cataract model in rats. Based on the hypothesis that AA may suppress cataract formation through its antioxidant and anti-inflammatory properties. In this study, an experimental cataract model was created with Na selenite and treated with AA. Cataract stages were clinically evaluated. In lens tissues, levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), calcium (Ca) ions, Ca-ATPase activity, and the expression of Bax and Bcl-2 proteins were measured, and Bax/Bcl-2 ratios were analyzed. The findings demonstrated a significant increase in the mean cataract grade in the sham group compared to the control group (p<0.01). However, this parameter was significantly decreased in Group 3 (10 mg/kg) and Group 4 (30 mg/kg) (p<0.05 and p<0.01, respectively). SOD levels were significantly decreased in the sham group relative to controls (p<0.01), whereas a significant increase was observed in both Group 3 and Group 4 (p<0.01 for both). GSH-Px levels were also decreased in the sham group (p<0.05); no significant change was found in Group 3 (p=0.243), but a significant increase was noted in Group 4 (p<0.01). MDA levels were markedly increased in the sham group (p<0.01) and significantly decreased following treatment in Group 3 and Group 4 (p<0.05 and p<0.01, respectively). Calcium ion levels showed a significant increase in the sham group (p<0.05), while both treatment groups demonstrated a significant decrease (p<0.01 for both). Ca-ATPase activity was reduced in the sham group (p<0.01), but significantly increased in Groups 3 and 4 (p<0.05 and p<0.01, respectively). Finally, the Bax/Bcl-2 ratio was significantly elevated in the sham group (p<0.01) and reduced in Groups 3 and 4 (p<0.05 and p<0.01, respectively). These findings demonstrate that AA administration significantly reduces cataract development, improves oxidative stress markers, and modulates intracellular apoptotic mechanisms. While both tested doses exhibited therapeutic effects, the improvements in biochemical parameters were more pronounced and statistically significant in Group 4, indicating a dose-dependent effect of AA and suggesting that its therapeutic efficacy increases with higher doses. The results support the potential of AA as a pharmacological agent for the prevention or deceleration of cataract progression. Keywords: Cataract, Asiatic acid, Antioxidant, Sodium selenite, Oxidative stress, Apoptosis