Alpha-pinene mitigates renal ischemia-reperfusion injury via anti-oxidant, anti-inflammatory, anti-apoptotic effects and favorable eNOS/iNOS shifts in rats

Acute kidney damage frequently results from renal ischemia-reperfusion (RI/R). Alpha-Pinene (AP), a plantderived monoterpene, has antioxidant, anti-inflammatory, and anti-apoptotic properties. We investigated whether AP limits early kidney damage after experimental RI/R. Female Wistar rats (n = 7 per group) were assigned to Sham, RI/R, RI/R + AP 50 mg/kg, or RI/R + AP 100 mg/kg. After 45 min of clamping both renal pedicles, a 24-h reperfusion period ensued. AP (i.p. immediately before reperfusion) was administered immediately before reperfusion. ELISA for inflammatory cytokines (IL-1 beta, TNF-alpha, IL-10), oxidative stress markers (MDA, IMA, SOD), and nitric oxide synthase isoforms (iNOS, eNOS). Histopathology (hematoxylin/Mallory's trichrome staining) for structural kidney injury scoring. Immunohistochemistry for apoptosis/autophagy markers (Bcl-2, cleaved caspase-3, LC3B) and NF-kappa B p65. In kidney homogenates, RI/R increased IL-1 beta, TNF-alpha, MDA, IMA, and iNOS and reduced IL-10, SOD, and eNOS compared to Sham. AP counteracted these alterations in a manner proportional to the dose; the 100 mg/kg dose most consistently approached Sham values. Histology showed diffuse vascular congestion/hemorrhage, tubular degeneration, and widening of Bowman's space after RI/R-all ameliorated by AP, with milder lesions at 100 mg/kg. Immunohistochemistry demonstrated lower cleaved caspase-3, LC3B, and NF-kappa B p65 (trend) with AP, alongside higher Bcl-2, supporting anti-apoptotic and anti-autophagic effects. A single intraperitoneal dose of AP administered immediately before reperfusion mitigated early renal injury after RI/R by improving redox balance, dampening inflammatory signaling, shifting the eNOS/iNOS profile toward endothelial protection, and reducing structural damage. AP merits further study as a potential adjunct to limit I/R-related kidney injury, including longer follow-up with functional renal endpoints and expanded dosing/timing strategies.