Does zinc pretreatment have a protective effect on the injury severity of the newborn rats small intestine subjected to hypoxia-reoxygenation injury? Çinko tedavisi hipoksi reoksijenasyonun neden oldugu yenidoǧan rat incebarsak hasanna karşi koruyucu mudur?


ÖZKAN K. U. , Inanç F., Boran Ç., Kilinç M.

Cocuk Cerrahisi Dergisi, vol.19, no.1, pp.6-12, 2005 (Refereed Journals of Other Institutions) identifier

  • Publication Type: Article / Abstract
  • Volume: 19 Issue: 1
  • Publication Date: 2005
  • Title of Journal : Cocuk Cerrahisi Dergisi
  • Page Numbers: pp.6-12

Abstract

Aim: It is tought that free radical damage following ischemia reperfusion injury is an important factor for the pathogenesis of necrotizing enterocolitis (NEC). It is demonstrated that metal aspartates reduce free radical damage in many tissues. Thus, in this study, we aimed to evaluate whether zinc pretreatment has a protective effect on injury severity the newborn rats small intestine subjected to experimental necrotizing enterocolitis. Method: A total of 30 newborn Sprague-Dawley rats (from seven different mothers) collected immediately after birth to prevent suckling of maternal milk were divided into three groups. The groups were labeled as group 1, control; group 2, hypoxia-reoxygenation; and group 3, zinc-hypoxia-reoxygenation group. The rats of group 3 were pretreated with "zinc bis DL hydrogen aspartate" (50 mg/kg) one hour before experiments via subcuticular injection then rat pups in group 2 and group 3 were stressed twice daily with asphyxia followed by cold (+4°C for 10 min) to induce hypoxic intestinal injury which is relevant to human necrotising enterocolitis. % 100 CO2, inhalation for ten minutes in a chamber followed 10 minutes of % 100 O2 inhalation was the asphyxia model repeated twice daily. After hypoxia-reoxygenation and cold stres, newborn rats were returned to their mother's cages. 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 and examined macroscopically. A 3-cm section of distal ileum and 1 g liver tissues from each animal was taken for histopathological and biochemical examinations. Histologic changes in ileal architecture were scored and gradedjrom 1 to 5 and epidermal growth factor receptors (EGFR) were evaluated immunohistochemically. The remaining intestinal tissues and liver tissues of the animals were used to measure the levels of malondialdehyde (MDA) and nitrit. Also, zinc levels were measured in all tissues by atomic absorbtion spectrophotometry. Results: Typical signs of hypoxia induced intestinal injury were observed in groups 2 and 3, macroscopically. Histopathological grading and immunohistochemical EGFR evaluation showed less damage in group 3 compared to group 2 (p<.05). In group 2, MDA and nitrit levels in all tissues were increased (p<.001) and zinc levels were decreased (p<.001) in comparison to group 3. Conclusion: Zinc pretreatment has a protective effect on hypoxia reoxygenation induced intestinal injury in newborn rats.