Abstract Objective Gastroschisis (GS) is a congenital anomaly in the abdominal wall with the intestinal loops exiting laterally to the umbilicus. The contact of the loops with Amniotic Fluid (AF) causes an inflammatory process in the exposed part, leading to an extended hospital stay and an increased risk of morbidity due to alterations related to intestinal motility. The authors aimed to evaluate the time of exposure to the AF in the experimental GS and to search for potential biomarkers of intestinal inflammation by measuring microRNAs. Methods Rat fetuses were divided into three groups: a) CONTROL, b) GS reared on day 18 (GS = 18), and c) GS reared on day 19.5 (GS = 19) (term = 22 days). On day 21.5, the fetuses were removed for biometric parameters and biochemical analyses: 1) Biometrics: Body and Intestinal Weight (BW, IW), and intestinal-body weight ratio (IW/BW); 2) Descriptive histopathology and 3) miR-143 quantification by real-time Polymerase Chain Reaction (PCR). Results BW was higher in CONTROL than GS 18 and G19 (p < 0.05). IW, IW/BW, intestinal water, and mRNA-143 were higher in GS 18 and GS 19 than in CONTROL, and GS 18 was higher than GS 19 (p < 0.05). The average of the inflammation score from the intestinal wall with mucosal inflammation and intra-epithelial lymphocytes shows worst in GS 18 and GS 19 vs. CONTROL (p < 0.05). Conclusions The tissue expression of mRNA-143 and the morphological changes in the intestine of GS worsened according to the time of exposure to AF, which could be a possible marker of fetal intestinal damage. umbilicus (AF part motility microRNAs groups b 1 18, , 18) c 195 5 19. term 2 days. days . days) 215 21 21.5 analyses Biometrics BW, (BW IW IW) intestinalbody body IW/BW IWBW (IW/BW) 3 miR143 miR 143 miR-14 realtime real PCR. PCR (PCR) G G1 p 0.05. 005 0.05 0 05 0.05) water mRNA143 mRNA mRNA-14 intraepithelial intra epithelial vs damage 21. (IW/BW miR14 14 miR-1 (PCR 00 0.0 mRNA14 mRNA-1 miR1 miR- 0. mRNA1 mRNA-

Resumo Introdução Trauma oclusal primário (TO) é a injúria causada no periodonto de inserção de dentes com periodonto de altura normal devido a forças oclusais que excedem sua capacidade adaptativa. Objetivo Avaliar histometricamente a reabsorção óssea alveolar na região da furca do 1º molar inferior em ratos submetidos experimentalmente a 2 modelos de sobrecarga oclusal. Material e método 45 animais aleatoriamente divididos em 3 Grupos: Interferência Oclusal (GI, n = 15) - fixação de um segmento de fio ortodôntico na face oclusal do 1º molar inferior; Sobrecarga Oclusal (GS, n = 15) - desgaste das cúspides dos molares inferiores contralaterais e dos 2º e 3º molares do lado do 1º molar que teve suas dimensões mantidas; Grupo Controle Negativo (CN, n = 15) - avaliação das dimensões iniciais do ligamento periodontal. Cinco animais/grupo foram submetidos à eutanásia após 14, 21 e 28 dias. Resultado A avaliação intergrupos mostrou que houve reabsorção óssea significativa em GI (p<0,001) e GS (p<0,01) quando comparados com CN. O grupo GI teve reabsorção óssea significativamente maior quando comparado ao grupo GS em 14 (p<0,01), 21 (p<0,01) e 28 dias (p<0,01). A avaliação intragrupos não mostrou influência significativa do tempo na reabsorção óssea em GI e GS, independente da técnica utilizada (p>0,05). A espessura do ligamento periodontal manteve-se estável no grupo CN (p>0,05). Conclusão GI e GS foram eficazes na reprodução experimental do TO e GI promoveu maior reabsorção óssea alveolar quando comparado a GS, mostrando que o impacto causado pela sobrecarga oclusal no grupo GI aumentou a lesão por TO.

Abstract Introduction Primary occlusal trauma (OT) is an injury of the periodontium with normal height as a result of occlusal forces which exceed their adaptive capacity. Objective To evaluate, histometrically, the alveolar bone loss in the furcation region of rats experimentally submitted to 2 models of occlusal overload. Material and method 45 animals randomly divided into 3 groups: Occlusal Interference (OI, n = 15) - fixing an orthodontic wire segment on the occlusal surface of the first lower molar; Occlusal Overload (OO, n = 15) - wearing of the cusps of the lower contralateral molars, the second and third molars next to the first molar that had its dimensions maintained; Negative Control (NC, n = 15) - evaluation of the initial dimensions of the periodontal ligament (PL). Five animals / group were sacrificed after 14, 21 and 28 days. Result Intergroup evaluation showed significant bone loss in OI (p<0.001) and OO (p<0.01) compared to NC. OI had significantly higher bone loss compared to OO at 14 (p<0.01), 21 (p <0.01) and 28 days (p<0.01). The intragroup evaluation showed no significant influence of time on bone loss in OI and OO, regardless of the technique used (p>0.05). The thickness of the PL remained stable in NC (p>0.05). Conclusion OI and OO were effective in the experimental reproduction of OT, and OI promoted greater alveolar bone loss compared to OO, showing that the impact of occlusal overload in OI increased the extent of the OT injury.