Modelo experimental para criação intra-utero de fissuras labiopalatinas em ratos / Experimental model for intrauterine cleft lip and palate in rats

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Cleft lip and palate (CLP) are the most frequent congenital defects of the face. CLP can occur in association, although they don t share the same etiology. These defects may impose face abnormalities and speech problems. Animal models have been used to study embriogenesis and pathogenesis of cleft lip and palate and surgical cleft confection in fetuses of both large and small animals have been described. Fetal rat model has been validated and has the advantages of lower cost, shorter gestation, more fetuses per pregnancy and less abortion and premature labor. Although rat model is in use, the ideal gestational day for cleft confection has never been studied. This study aimed to validate the surgical model for CLP in rat fetuses, determining the ideal gestational day. Pregnant Sprague-Dowley rats (n=16) underwent laparotomy for fetal exposure in three gestational moments (day 17.5, 18.5 and 19.5), being term on 22nd day. Fetal head was exposed and a 2mm punch used to mark the superior lip between midline and left commissure and then CLP created laterally through a triangular excision. For every operated fetus one control (C) and one Sham (S) fetus were present. On day 21.5, fetuses were removed, photographed, weighed and euthanized. Heads were fixed in formaline and 5µm slices stained with hematoxylin eosin for cleft visualization and analysis of reepitelization. A total of 45 fetuses were included, being 15 CLP, 15 C and 15 S. Macroscopic analysis of CLP revealed depression at the defect, lip retraction and asymmetry. Microscopy demonstrated on day 17.5 absence of lip interruption and partial wound regeneration. On day 18.5 lip interruption and partial wound regeneration were identified. On day 19.5 there was complete lip interruption as well as reepitelization of wound borders. All fetuses presented same macroscopic findings, independent of gestational day of operation. Differently, histology demonstrated that fetuses operated on day 19.5 presented CLP most similar to those occurring spontaneously or induced. In this study we confirmed model feasibility and demonstrated that the best gestational age to perform CLP is on day 19.5 of gestation.

ASSUNTO(S)

fetus rats cleft pallate feto fissura palatina fenda labial ratos - estudos experimentais experimental model

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