Does β-caryophyllene protect against renal dysfunction following ischemia-reperfusion injury in the rat?

Introduction: Renal ischemia-reperfusion injury (IRI) causes renal functional alterations which may lead to permanent renal impairment. β-caryophyllene (BCP), a natural bicyclic sesquiterpene, is an important constituent of many edible plants including spices. It is an FDA-approved food additive which possesses potent anti-inflammatory and antioxidant activities and has been shown to protect against chemotherapeutics-induced organ toxicities and against ischemic injuries to heart, liver and brain. Oxidative stress and inflammation is a main accompaniment of renal dysfunction, however, the effect of BCP on IRI-induced renal dysfunction has not been investigated yet and therefore the aim of this study was to investigate the effect of BCP on IRI-induced renal dysfunction. Methods: Wistar rats underwent left renal warm ischemia for 40 minutes. G-BCP (n=13) received oral BCP (50 mg/kg/day) dissolved in a vehicle starting 7 days prior to IRI and continued 7 days thereafter when the renal functions of both kidneys and the markers of oxidative stress and pro-inflammatory cytokines were measured. G-Vx (n=13) underwent similar protocol but received vehicle only. Results: IRI affected hemodynamic (renal blood flow and glomerular filtration rate) and tubular (urine volume, total and fractional urinary sodium excretion) parameters in the left ischemic kidney in G-Vx. Though, BCP did not affect any of these alterations in the ischemic kidney (P>0.05 for all). However, it attenuated the alterations in malondialdehyde (MDA) and glutathione (GSH) in the left ischemic kidney in G-BCP compared to G-Vx (9.3±2.1 vs. 4.8±1.0, P=0.047 and 18.1±2.5 vs. 13.6±1.7, P=0.09, respectively). Conclusion: Our study results demonstrate that BCP attenuated the alterations in some of the oxidative stress markers. However, these were not translated in to the protective effects on the haemodynamic and tubular glomerular functions when measured seven days post-IRI. This suggests that BCP has a weak reno-protective effect under ischemic conditions.