Effect of Leptin Treatment on Small Intestinal Damage Induced by Hypoxia Reoxygenation in Newborn Rats

Abstract

Objective: To evaluate whether leptin has an protective effect on small intestinal damage induced by hypoxia reoxygenation in newborn rats. Materials and Methods: There were three equal Groups each consisted of 10 newborn rats. Group 1; control, Group 2; hypoxia-reoxygenation, Group 3; leptin-hypoxia-reoxygenation. The rats of Group 3 were pretreated with leptin (20 microgram/kg) one hour before experiments then rat pubs in Group 2 and Group 3 were stressed twice daily with asphyxia followed by cold (+4º C for 10 min). Breathing 100% CO2 for ten minutes in a chamber followed 10 minutes 100% O2 breathing was the asphyxia model. This protocol was repeated for the following two days and the rat pups were decapitated on the third day. The entire gastrointestinal tract was removed. A 3-cm section of distal ileum from each animal was taken. Histopathological damage and epidermal growth factor receptors (EGFR) are evaluated. For biochemical evaluation, tissue malondialdehyde (MDA) and nitric oxide (NO) levels were measured. Results: In Group 2 and Group 3 macroscopic intestinal injuries were observed. Histopathological grading and immunohistochemical EGFR evaluation showed similar damage in the Group 2 and the Group 3. In these Groups tissue MDA levels were also in the same ranges but NO levels were different each other with the higher levels of Group 2. Group 3 had same NO levels with control Group. Conclusions: Leptin pretreatment has no protective effect on hypoxia reoxygenation induced intestinal injury in newborn rats although it changes NO levels in the injured intestine.

Keywords

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Leptin Tedavisi Yeni Doğan Rat İncebarsağında Hipoksi/Reoksijenasyon Hasarına Karşı Koruyucu mudur?

Öz

Amaç: Hipoksi reoksijenasyonun neden olduğu yenidoğan rat incebarsak hasarına leptin'in etkinliğini arastırmak. Gereç ve Yöntem: Doğum sonrası rastgele seçilmiş 30 adet yavru rat kendi aralarında üç eşit gruba bölünerek deneysel gruplar oluşturuldu. Grup 1 kontrol, Grup 2 hipoksi-reoksijenasyon , Grup 3 leptin hipoksi-reoksijenasyon grubu olarak belirlendi. Grup 3 deki yavru ratlara deneysel işlemden 1 saat önce ciltaltı enjeksiyonla 20 mikrogram/kg leptin verildi. Bu gruplardaki yavrular bir cam kavanoz içerisine koyuldular. Kavanoz içerisindeki hava aspiratör yardımı boşaltılıp tekrar karbon dioksit ile dolduruldu. Yavruların 10 dk bu ortamda solumaları sağlandı ve ardından kavanoz oksijen ile dolduruldu. Böylece reoksijenasyon yapılmış oldu. Onuncu dakikadan sonra yavrular tekrar dışarı alındı ve 10 dakika soğuğa maruz bırakıldı. Bu işlem birkez daha baştan sona tekrarlandı. Uygulanan bu işlemler serisi 2. ve 3. günlerde de tekrarlandı. Üçüncü günü yavrular dekapite edildi ve gasrointestinal sistemleri çıkarıldı. Histopatolojik ve biyokimyasal inceleme için terminal ileumdan 3 cm uzunluğunda ince barsak dokusu alındı. Histopatolojik incelemede ileum hasarı bakıldı ve immunhistokimyasal boyama ile epidermel büyüme faktörü reseptorleri (EBFR) araştırıldı. Kalan barsak dokularında malondialdehit (MDA), ve nitrik oksit (NO) düzeyleri ölçüldü. Bulgular: Grup 2 ve grup 3 de tipik NEK bulguları gözlendi. Histopatolojik incelemelerde gruplar farksızdı (P>.05) Yine grup 2 ve grup 3 de MDA düzeyleri farksızdı (p>.05) Ancak bu grupların NO düzeyleri birbirinden farklıydı . NO Grup 2 de yüksek ve Grup 3 de kontrol grubu ile aynıydı (P>.05) Sonuç: Leptin'in NO düzeylerini değiştirmesine rağmen yeni doğan ratlarda hipoksi reoksijenasyonun neden olduğu barsak hasarını önleyici etkisi yoktur.

Anahtar Kelimeler

• Leptin, hipoksi/reoksijenasyon, nekrotizan enterokolit

Kaynakça

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33. Kabul Tarihi:09.03.2005