Flavonoid-rich extract of <i>Parquetina nigrescens</i> prevents intestinal ischemia-reperfusion injury in Wistar rats via modulation of inflammatory cytokines and antioxidant defense

Abstract

The search for relatively safe and cost-effective strategies at minimizing tissue damage following acute inflammatory bowel conditions still continues. To further explore the mechanisms of protection by Parquetina nigrescens in gut ischemia-reperfusion injury, the present study sought to investigate the effects of the flavonoid-rich extracts of Parquetina nigrescens (FPN) on serum levels of inflammatory cytokines (TNF-alpha and IL-1beta), the oxidant-antioxidant status, as well as the morphology of the intestinal mucosa in a rat model of ischemia-reperfusion injury. Thirty six male Wistar rats were randomly allocated into 6 groups with the sham-operated group subjected to laparotomy only. In the ischaemia-reperfusion (IR) group, the superior mesenteric artery (SMA) was occluded for 45 minutes, followed by reperfusion for another 45 minutes. Other groups had ischemic pre-conditioning (IP), melatonin (10 mg/kg), FPN1 (250 mg/kg) or FPN2 (500 mg/kg) before IR. Serum cytokine levels were determined, histopathological examination and biochemical analyses of small intestines were carried out. IR produced significant increases (p<0.05) in MDA and TNF-alpha with significant reductions (p<0.05) in GSH, GPx and SOD. FPN2 produced the best amelioration of effects of IR injury on MDA, H₂O₂, GSH and SOD, as well as the best preservation of mucosal integrity at histology. The increased TNF-alpha level was, however, best ameliorated with ischemic preconditioning. Our results provide evidence for the amelioration of IR injury by flavonoids derived from Parquetina nigrescens via anti-inflammatory effects, mainly involving TNF-alpha reduction. This effect was also positively correlated with reduction in oxidative damage.