Neonatal necrotizing enterocolitis rat model attenuated by a remote ischemic preconditioning in the pregnant

Abstract

Neonatal necrotizing enterocolitis rat model attenuated by a remote ischemic preconditioning in the pregnant 1Acta Cir. Bras. 2017;32(3):236-242 Abstract Purpose: To evaluate the effect of remote ischemic preconditioning (r-IPC) administered to pregnant rats, in the ileum of newborn rats subjected to hypoxia and reoxygenation. Methods: We used three pregnant rats and their newborn rats distributed in three groups: 1) Control (C) -Newborn rats born from a pregnant rat which did not undergo any intervention; 2) Hypoxia-Reoxygenation (H/R) -Newborn rats born from a pregnant rat which did not undergo any intervention, and were subjected to hypoxia-reoxygenation; 3) Remote Ischemic Preconditioning (r-IPC) -newborn rats born from a pregnant rat which was subjected to remote ischemic preconditioning twenty-four hours before giving birth and the newborn rats were subjected to hypoxia-reoxygenation. Segments of ileum were prepared for histological analysis by HE and immunohistochemistry by the Ki67 to evaluate cell proliferation, crypt depth and villus height and evaluation of apoptosis by cleaved caspase-3. Results:The intensity of the lesions was lower in the r-IPC than in the H/R group, showing significant difference (p<0.01). The r-IPC group showed a higher proliferative activity compared to the H/R group (p<0.01), with deeper crypts (r-IPC > H/R -p < 0.05), and higher villi, showing significant difference (r-IPC > H/R -(p <0.01). The occurrence of apoptosis in the H/R group was lower in comparison to groups C and r-IPC, with significant difference (H/R < r-IPC; p<0.05). Conclusion:The remote ischemic preconditioning applied to the pregnant rat protected the ileum of newborn rats subjected to hypoxia and reoxygenation, with decreased intensity of the lesions in the ileum mucosa and preservation of proliferative activity, keeping the villus height and crypt depth similar to group C. Key words: Enterocolitis, Necrotizing. Ischemic Preconditioning. Pregnancy, Animal. Rats. The characteristic of r-IPC is the occurrence of two distinct phases of protection: early, which begins immediately after reperfusion, having protective action in a period of two to three hours, and the late one, which manifests itself between twelve and twenty-four hours after the initial reperfusion, acting for up to 72 hours 6,12 . 8-Experimental SurgeryIn our lab, it was shown that r-IPC applied on pregnant rat minimized the occurrence of colonic NEC in their pups 13 . Considering the systemic effect of r-IPC against IR lesions and that ischemia is a relevant factor in the occurrence of NEC; further, the ileum is also compromised in this disease; it was decided to test the hypothesis that r-IPC applied in pregnant rat might attenuate the small bowel lesions in an experimental NEC model. ■ MethodsThe experiments were conducted after approval by the Research Ethics Committee, Universidade Federal de São Paulo, under protocol no. CEP 0341/07.It was used three pregnant rats and their 31 newborns from the OUTBRED EPM-1 Wistar strain (Rattus norvegicus ...

Oxidative stress assessment in intestine of newborn rats submitted to hypoxia and reoxygenation with tadalafil

“…However, even though the drug has demonstrated to be effective, the histological evaluation did not show lesion compatible with the damages that occur in NEC, as in our previous studies 14 - 16 . The hydropic degeneration degree and ballooning of enterocytes may be a precursor lesion of necrosis, corresponding to an initial stage of the injury proposed previously 17 , 18 .…”

“…Gomes et al 16 had to move to another experimental model 10 , augmenting the time of hypoxia exposition, to obtain a similar degree of lesion obtained by Cintra et al 15 . This protocol 10 , already consolidated, which reproduces the issue of oxidative stress and intestinal mucosa injury, it was not enough to get the same morphological alterations.…”

Intestinal tract and parenteral multi-organ sequential pathological injury caused by necrotizing enterocolitis

“…Their average weight is 6.7 g, and their gender is random. A rat model for NEC was established by artificial feeding of dairy substitutes, hypoxia and cold stimulation (100% nitrogen hypoxia 90 s, 4°C cold stimulation 10 min, twice a day for 3 consecutive days) [6][7][8]. In the NEC group, the induction of NEC was initiated on the 3rd day after birth.…”

Intestinal tract and parenteral multi-organ sequential pathological injury caused by necrotizing enterocolitis

“…Their average weight is 6.7g, and their gender is random. A rat model for NEC was established by arti cial feeding of dairy substitutes, hypoxia and cold stimulation (100% nitrogen hypoxia 90 seconds, 4℃ cold stimulation 10 minutes, twice a day for 3 consecutive days) [6][7][8]. In the NEC group, the induction of NEC was initiated on the 3rd day after birth.…”