EC Pharmacology And Toxicology

Diabetic retinopathy (DR) is a severe complication of diabetes mellitus characterized by oxidative stress and impaired retinal vascular function. This study investigates the therapeutic potential of Punarnavine, an experimental drug, in mitigating DR in streptozotocin (STZ)-induced diabetic rats. Animals were treated with low (DR+PNLD) and high (DR+PNHD) doses of Punarnavine, and various biochemical assays were conducted to evaluate oxidative stress markers and antioxidant enzyme activities. Treatment with Punarnavine significantly reduced malondialdehyde (MDA) levels, indicative of decreased lipid peroxidation, in both DR+PNLD (2.48 nmol/mg protein, SD = 0.56) and DR+PNHD (2.22 nmol/mg protein, SD = 0.18) groups compared to untreated DR rats. Catalase activity was enhanced in DR+PNHD rats (71.42 units/mg protein, SD = 0.63), showing robust antioxidant defence mechanisms. Similarly, superoxide dismutase (SOD) activity was significantly elevated in DR+PNHD rats (26.1 units/mg protein, SD = 1.28), underscoring effective antioxidant capacity. Glutathione (GSH) activity was also markedly increased in DR+PNHD rats (46.55 units/mg protein, SD = 1.17), further supporting enhanced antioxidant defences. Assessment of vascular permeability as a measure of retinal dysfunction revealed variable responses: DR+PNLD (20.48 µg/mL, SD = 1.05) displayed mixed outcomes, whereas DR+PNHD (20.43 µg/mL, SD = 0.59) showed moderate improvement compared to untreated DR rats. In conclusion, Punarnavine exhibits potent antioxidant properties by reducing oxidative stress markers and enhancing antioxidant enzyme activities in STZ-induced diabetic retinopathy. While high-dose Punarnavine shows promising efficacy in improving retinal antioxidant defences and reducing vascular dysfunction, further studies are warranted to optimize therapeutic outcomes for diabetic retinopathy management.

 Keywords: Diabetic Retinopathy; Punarnavine; Oxidative Stress; Antioxidant Enzymes; Streptozotocin

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