Ameliorative Effects of Methanol Leaf Extract of Justicia carnea on Streptozotocin-Induced Diabetic Organopathy in Wistar Rats: A Histopathological Assessment

Diabetes mellitus is a chronic metabolic disorder marked by persistent hyperglycemia, which progressively impairs multiple organ systems. This study evaluated the histopathological effects of streptozotocin (STZ)-induced diabetes on the pancreas, liver, and kidneys of Wistar rats, and also assessed the protective potential of the methanol leaf extract of Justicia carnea. Thirty-six male Wistar rats were assigned to six groups (n = 6). Group 1 served as the normal control, while diabetes was induced in the remaining groups with STZ (50 mg/kg). Group 2 remained untreated, Group 3 received metformin (50 mg/kg), and Groups 4 – 6 were administered 100, 200, and 500 mg/kg of J. carnea extract, respectively, for 28 days. Untreated diabetic rats showed severe hepatic lesions, including marked vascular congestion and periportal inflammation, whereas the extract-treated groups exhibited progressive restoration of normal hepatic architecture, most notably at 200 and 500 mg/kg. Renal tissues from untreated diabetics displayed glomerular shrinkage, tubular necrosis, and interstitial congestion; these abnormalities were substantially reversed by J. carnea, with the highest dose producing histology comparable to that of normal and metformin-treated rats. Pancreatic sections from diabetic controls revealed pronounced islet degeneration and vascular congestion, while extract treatment resulted in dose-dependent improvement, including islet regeneration and reduced inflammation. Overall, Justicia carnea methanol leaf extract demonstrated significant protective and restorative effects on pancreatic, hepatic, and renal tissues in STZ-induced diabetic rats. These results support its potential as a promising phytotherapeutic agent for mitigating diabetes-related organ damage and as a possible adjunct to conventional therapies.