Enteral resveratrol supplementation attenuates intestinal epithelial inducible nitric oxide synthase activity and mucosal damage in experimental necrotizing enterocolitis.
OBJECTIVE
The release of various enzymes including inducible nitric oxide synthase (iNOS) leads to enterocyte apoptosis through free nitrogen radicals, which in turn leads to impaired mucosal barrier and bacterial translocation with resultant sepsis in necrotizing enterocolitis (NEC). Resveratrol, a polyphenol compound from phytoalexins with antioxidant and scavenger properties, also play a critical role in modulating key enzymes in cell cycle including iNOS. We therefore hypothesized that resveratrol would prevent mucosal damage in experimental NEC in rats.


METHODS
Newborn rats were randomized into 3 groups: group 1 was left to breast-feed (BF), whereas group 2 (NEC) was induced by enteral formula feedings twice daily and by being subjected to hypoxia thrice. The third group (R) received the same treatment as the NEC group but the enteral feeds were supplemented with resveratrol. Rats were killed on day 4, and their terminal ileal samples were harvested for histopathologic analysis. Expression of iNOS was assessed by sodium dodecyl sulfate polyacrylamide-gel electrophoresis analysis and immunohistochemistry. Band densities were quantified by using the software NIH image.


RESULTS
The epithelial structure in group BF was normal. In the NEC group, there were marked loss of the brush border, vacuolization, and necrosis. The epithelial structure was found to be preserved in group R. Western blot analysis revealed marked elevation in the expression of iNOS protein at 130 kD molecular weight (band densities in groups BF, NEC, and R were 0.3 +/- 3.5, 3.7 +/- 2.9, and 0.6 +/- 5.1, respectively; P < .01). Immunohistochemical analysis revealed that iNOS staining was significantly increased in the NEC group, whereas it remained minimal for the BF and R groups. Ileal tissue nitrate/nitrite levels for groups BF, NEC, and R were 178.3 +/- 7, 191.4 +/- 4.1, and 181 +/- 3.6 micromol/(L x g), respectively (P < .01).


CONCLUSIONS
These findings may provide insights for the beneficial effect of enteral resveratrol supplementation on inflammatory conditions of the bowel including NEC through attenuating the release of iNOS and preservation of mucosal integrity.
Ergün
Orkan
O
Department of Pediatric Surgery, Ege University Faculty of Medicine, Izmir 35100, Turkey. orkan.ergun@ege.edu.tr
Ergün
Güliz
G
Oktem
Gülperi
G
Selvi
Nur
N
Doğan
Hakan
H
Tunçyürek
Müge
M
Saydam
Güray
G
Erdener
Ata
A
D000284:Administration, Oral; D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D020345:Enterocolitis, Necrotizing / Q000188:drug therapy* / Q000201:enzymology / Q000209:etiology / Q000473:pathology; D005260:Female; D007082:Ileum / Q000187:drug effects / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D008871:Microvilli / Q000201:enzymology; D009566:Nitrates / Q000032:analysis; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors*; D009573:Nitrites / Q000032:analysis; D011247:Pregnancy; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D000077185:Resveratrol; D013267:Stilbenes / Q000008:administration & dosage / Q000627:therapeutic use*
D000975:Antioxidants; D009566:Nitrates; D009573:Nitrites; D013267:Stilbenes; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D000077185:Resveratrol