Oxygen free radical induced damage during intestinal ischemia/reperfusion in normal and xanthine oxidase deficient rats.
This study looks at the role of xanthine oxidase (XO) in ischemia/reperfusion (I/R) induced intestinal mucosal damage using normal and xanthine oxidase deficient rats. Tungstate feeding for 3 days depleted the intestinal mucosal XO by 80%. A ligated loop of the rat small intestine (both normal and XO-deficient) was subjected to 1 h of total ischemia followed by 5 min revascularisation. The ensuing mucosal damage was assessed by biochemical and histological studies. Ischemia or I/R increased the XO levels in normal rats without any change in XO-deficient rats. Myeloperoxidase (a neutrophil marker) level was increased in both group of rats but it was comparatively higher in the XO-deficient rats. Accumulation of peroxidation products such as malondialdehyde, conjugated diene and increased production of hydroxyl radicals by microsomes were seen after ischemia and I/R and were similar in normal and XO-deficient rats. Studies on other parameters of peroxidation showed a decrease in polyunsaturated fatty acids and alpha-tocopherol, an increase in cysteine and cystine levels after I/R and were similar in both normal and XO-deficient rats. Histological results indicated gross morphological changes in the intestinal mucosa due to ischemia and I/R, and the damage was more severe in XO-deficient rats. These observations suggest that oxygen-derived free radicals are involved in the intestinal mucosal damage during I/R and infiltrated neutrophils rather than XO may be the primary source of free radicals under these conditions.
Nalini
S
S
Wellcome Trust Research Laboratory, Department of Gastrointestinal Sciences, Christian Medical College & Hospital, Tamilnadu, India.
Mathan
M M
MM
Balasubramanian
K A
KA
D000818:Animals; D005609:Free Radicals; D007413:Intestinal Mucosa / Q000098:blood supply / Q000201:enzymology / Q000473:pathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D012016:Reference Values; D015427:Reperfusion Injury / Q000209:etiology*; D014969:Xanthine Oxidase / Q000172:deficiency*
D005609:Free Radicals; D017382:Reactive Oxygen Species; D014969:Xanthine Oxidase