Original article
Protective effects of Y-27632 on hypoxia/reoxygenation-induced intestinal injury in newborn rats

https://doi.org/10.1016/j.jpedsurg.2010.11.034Get rights and content

Abstract

Background/Purpose

Necrotizing enterocolitis (NEC) is a major cause of mortality in neonates and is associated with a disruption in the protective intestinal barrier. The precise cause of NEC is elusive. However, ischemia/reperfusion injury of the intestine has been considered a major contributing factor. We examined the role of Y-27632, a selective Rho-kinase inhibitor, on a hypoxia/reoxygenation (H/R)-induced intestinal injury of newborn rat pups.

Methods

Hypoxia/reoxygenation was achieved by placing rat pups in an airtight chamber aerated with 95% N2 + 5% CO2 for 10 minutes followed by 10-minute 100% oxygen. Forty newborn rat pups were randomly allocated into 4 groups. Group 1 served as untreated controls. The pups in group 2 were subjected to H/R only. In groups 3 and 4, the rats were treated with intraperitoneal injection of 0.3 and 3 mg kg−1 day−1 of Y-27632 for 5 days following H/R, respectively. The pups were killed 6 days following the H/R injury. Intestine specimens were evaluated for histopathology and biochemical investigation.

Results

The microscopic lesions in H/R rat pups were virtually the same as those seen in neonatal NEC, with severe destruction of villi and crypts. Hypoxia/reoxygenation resulted in significant elevation in malondialdehyde levels, but decreased tissue nitric oxide levels (P < .05). Protective effects of Y-27632 on H/R-induced intestinal injury of newborn rat pups were observed with a significant decrease in the intestinal injury score, suppression in malondialdehyde levels, and increase in nitric oxide levels (P < .05).

Conclusions

In this experimental study, Y-27632 significantly attenuated H/R-induced intestinal injury. These findings indicate that inhibition of Rho-kinase may offer a novel therapeutic approach in the treatment of NEC.

Section snippets

The animals

The investigation conforms with the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised 1996). The experimental protocol was reviewed and approved by the local ethics committee of the University of Gaziantep. The study was carried out on 1-day-old Wistar albino rat pups whose mothers were housed at 22°C to 24°C with a 12-hour light/12-hour dark cycle and supplied with standard rat chow and water ad libitum.

Experimental design

A

Histopathology

The microscopic lesions in H/R rat pups were similar to those seen in neonatal NEC, with severe destruction of villi and crypts (Fig. 1). Nonhypoxic rat pups had essentially no intestinal tract alteration. The results of the histopathologic examinations are shown in Fig. 2. Intestinal injury score of the H/R group was significantly higher when compared with the nonhypoxic untreated controls. Y-27632 treatment following H/R led to significant decrease in the intestinal injury score. The scores

Discussion

In this experimental study, H/R resulted in marked elevation in tissue MDA levels and decreased tissue NO levels in rat pup intestine. Histologic examination revealed that H/R led to injuries in the intestine, which were similar to those seen in neonatal NEC. The major novel finding of our study was that Y-27632 treatment after H/R injury demonstrated beneficial effects on H/R-induced intestinal injury in newborn rats. Y-27632 significantly decreased the severity of histologic lesions, resulted

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