Macaranga tanarius Reduces the Expression of Vascular Endothelial Growth Factor and Tumor Necrosis Factor-Alpha in Diabetic Retinopathic Rats

Diabetic retinopathy (DR), a microvascular consequence of diabetes mellitus, leads to blindness in the elderly due to damage to the retinal blood barrier. Macaranga tanarius (L.) Mull. Argument. Leaves (MT) include prenylflavonoids and other bioactive substances that are advantageous for managing diabetes mellitus. This study aimed to evaluate the efficacy of MT as an alternative treatment for DR by reducing levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α). Rats were divided into five groups (n=5 per group): Group I (diabetic control, NA-CMC 1%), Group II (positive control, glibenclamide 0.45 mg/Kg BW orally), and Groups III to V received ethanol extract of MT orally at doses of 0.64, 1.28, and 1.92 g/Kg BW, respectively. All groups were induced with STZ-NA (45 and 110 mg/kg BW intraperitoneally) and subsequently rested for four weeks before receiving treatment once daily for four weeks, after which the rats were confirmed to have diabetes mellitus with fasting blood glucose (FBG) levels ≥250 mg/dL. FBG was evaluated on days 3, 31, and 59, while TNF-α and VEGF levels were tested on days 31 and 59 using blood samples obtained from the orbital sinus. MT extract at a dosage of 1.92 g/kg BW can enhance body weight (p˂ 0.05), induce a 17.10% drop in FBG levels (comparable to glibenclamide's effect of 17.03%), and achieve a 57.06% and 52.39% decrease in TNF-α and VEGF levels, respectively, outperforming the other four groups. MT extract from these results proved to be an effective alternative treatment for DR in DM rats induced with STZ-NA.