Assessment of the protection of the bowel using hydrogel (biomaterial) in the experimental model of gastroschisis

Orientador: Lourenço Sbragia NetoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias MedicasResumo: Gastrosquise é um defeito congênito da parede abdominal anterior no qual as alças intestinais ficam herniadas e em contato com o líquido amniótico (LA). Assim, a exposição ao LA resulta em várias disfunções intestinais pós-natal. Para reduzir o tempo de exposição ao LA em modelo animal, usou-se um hidrogel de N-isopropilacrilamida (NIPAAm) copolimerizado com ácido acrílico (Aac), que rapidamente intumesce na presença de LA. O hidrogel foi usado para cobrir as alças expostas até o fim da gestação. A gastrosquise foi induzida em fetos de ratas fêmeas da raça Sprague-Dawley através de um corte paramediano à direita do cordão umbilical para exposição parcial das alças com 18,5 dias de gestação. Os fetos foram separados em quatro grupos: controle (C), apenas gastrosquise (G), gastrosquise + cobertura das alças com adesivo de fibrina - Beriplast® (GA) e gastrosquise + cobertura das alças com adesivo de fibrina e aderido um pedaço de hidrogel seco (GAH). Os animais foram colhidos por cesárea com 21,5 dias de gravidez e o hidrogel foi cuidadosamente removido. Os fetos e as alças intestinais foram pesados e análise morfométrica foi realizada. Resultados mostraram que o hidrogel após intumescimento pesou 34X que seu peso seco; ele possui carga elétrica assim como a maioria das proteínas presentes no LA e sua retirada não provocou lesão à camada serosa do intestino exposto como visto na MEV. A comparação dos grupos C e GAH com os grupos G ou GA mostrou que o peso, o diâmetro, a espessura das camadas e da parede intestinais foi significativamente menor nos grupos C e GAH quando comparados aos grupos G e GA indicando processo inflamatório. Sendo assim, a aplicação do hidrogel aderido pelo adesivo de fibrina mostrou servir como uma efetiva proteção das alças herniadas, com uma redução significante da inflamação na gastrosquise.Abstract: Gastroschisis is a congenital defect of the anterior abdominal wall which leads the fetal bowel to herniate into the amniotic cavity. There, exposition to amniotic fluid (AF), results in severe postnatal intestinal dysfunction. In order to reduce exposition time to AF in an animal model, has used a hydrogel of N-isopropylacrylamide (NIPAAm) copolymerized with acrylic acid (Aac), which undergoes rapid swelling in the amniotic fluid. The hydrogel was used to coat the bowel hernia until pregnance is completed. Gastroschisis was induced in the fetuses of female Sprague-Dawley rats by partial evisceration of the bowel through a right paramedian opening of the abdominal wall in day 18,5 of pregnancy. The fetuses were separated in four groups: control (C), gastroschisis alone (G), gastroschisis + coating of the bowel hernia with fibrin adhesive -Beriplast® (GA) and gastroschisis + coating of the bowel hernia with fibrin adhesive topped by a piece of adhered dry hydrogel (GAH). Animals were harvested by cesarean section at day 21.5 of pregnancy and the hydrogel was carefully removed. Fetuses and intestinal tract were weighed and morphometric analysis was performed. Results showed that the hydrogel weight was 34X heavier than its dry weight; its electric charge and also the AF charge were negative and there was no damage to serosa layer of the intestine exposed. Comparison of the C and GAH groups with G and GA showed that the bowel weight, diameter, the layers and wall thickness was significantly reduced in C and GAH compared to G and GA. Thus, application of the hydrogel bound onto the fibrin adhesive was shown to provide an effective protection of the herniated bowel, with a significant reduction of inflammation in gastroschisis.MestradoPesquisa ExperimentalMestre em Cirurgi

Experimental rat model for fetal growth restriction: effects on liver glycogen and intestinal and renal morphometry

OBJETIVO: avaliar a eficácia do modelo de RCIU por ligadura da artéria uterina simulando insuficiência placentária em ratos. MÉTODOS: fetos de ratas prenhes Sprague-Dawley foram divididos em três grupos: RCIU (restrição de crescimento intrauterino), com fetos submetidos à ligadura da artéria uterina com 18,5 dias de gestação (termo = 22 dias), C-RCIU (controle da restrição), com fetos do corno contralateral à ligadura, CE (Controle Externo), com fetos de ratas sem manipulação. Com 21,5 dias de gestação, foi realizada cesárea, os fetos foram pesados e dissecados para análise morfométrica e histológica do fígado, intestino e rins. RESULTADOS: os dados morfométricos avaliados mostraram o peso corpóreo (PC), hepático (PH) e intestinal (PI) dos fetos com RCIU menor que C-RCIU e CE (p<0,001). O peso placentário (PP), renal (PR) e as relações PH/PC, PI/PC e PR/PC não se alteraram. A espessura renal foi menor nos fetos com RCIU (p<0,001) e houve diminuição da camada mucosa e submucosa intestinal (p<0,05). A avaliação histológica mostrou diminuição do glicogênio hepático nos fetos com RCIU em relação aos grupos C-RCIU e CE. CONCLUSÕES: o modelo descrito foi eficiente e causou RCIU fetal simétrica com diminuição da maioria dos órgãos, especialmente do peso hepático, e alteração nos depósitos de glicogênio.PURPOSE: to evaluate the effectiveness of the IUGR model by uterine artery ligation mimicking placental insufficiency in rats. METHODS: sprague-Dawley rat fetuses were divided into three groups: IUGR (intrauterine growth restriction), with fetuses in the right horn of pregnant rats subjected to right uterine artery ligation at 18.5 days of gestation (term = 22 days); C-IUGR (control of restriction), with control fetuses in the left horn, and EC (external control), with fetuses of intact rats. Animals were harvested by cesarean section at day 21.5 days of gestation. Fetuses were weighed and then sacrificed. The intestine, liver, kidney and placenta were weighed and dissected for morphometric and histological analysis. RESULTS: the morphometric data showed decreased body weight (BW), liver weight (LW) and intestinal weight (IW) of fetuses with IUGR compared to C-IUGR and EC (p<0.001). The placental weight (PW), renal weight (RW) and LW/BW, IW/BW, and RW/BW ratios did not change. IUGR fetuses had decreased kidney thickness (p<0.001) and decreased thickness of the intestinal mucosa and submucosa (p<0.05). Histological evaluation showed reduction of liver glycogen storage in fetuses with IUGR compared to C-IUGR and CE. CONCLUSIONS: the model described was efficient and caused symmetric fetal IUGR with decreased size of most organs, especially the liver, and changes in glycogen stores

Experimental rat model for fetal growth restriction : effects on liver glycogen and intestinal and renal morphometry

avaliar a eficácia do modelo de RCIU por ligadura da artéria uterina simulando insuficiência placentária em ratos. fetos de ratas prenhes Sprague-Dawley foram divididos em três grupos: RCIU (restrição de crescimento intrauterino), com fetos submetidos à ligadura da artéria uterina com 18,5 dias de gestação (termo = 22 dias), C-RCIU (controle da restrição), com fetos do corno contralateral à ligadura, CE (Controle Externo), com fetos de ratas sem manipulação. Com 21,5 dias de gestação, foi realizada cesárea, os fetos foram pesados e dissecados para análise morfométrica e histológica do fígado, intestino e rins. os dados morfométricos avaliados mostraram o peso corpóreo (PC), hepático (PH) e intestinal (PI) dos fetos com RCIU menor que C-RCIU e CE (p<0,001). O peso placentário (PP), renal (PR) e as relações PH/PC, PI/PC e PR/PC não se alteraram. A espessura renal foi menor nos fetos com RCIU (p<0,001) e houve diminuição da camada mucosa e submucosa intestinal (p<0,05). A avaliação histológica mostrou diminuição do glicogênio hepático nos fetos com RCIU em relação aos grupos C-RCIU e CE. o modelo descrito foi eficiente e causou RCIU fetal simétrica com diminuição da maioria dos órgãos, especialmente do peso hepático, e alteração nos depósitos de glicogênio324FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP08/51497-9to evaluate the effectiveness of the IUGR model by uterine artery ligation mimicking placental insufficiency in rats. sprague-Dawley rat fetuses were divided into three groups: IUGR (intrauterine growth restriction), with fetuses in the right horn of pregnant rats subjected to right uterine artery ligation at 18.5 days of gestation (term = 22 days); C-IUGR (control of restriction), with control fetuses in the left horn, and EC (external control), with fetuses of intact rats. Animals were harvested by cesarean section at day 21.5 days of gestation. Fetuses were weighed and then sacrificed. The intestine, liver, kidney and placenta were weighed and dissected for morphometric and histological analysis. the morphometric data showed decreased body weight (BW), liver weight (LW) and intestinal weight (IW) of fetuses with IUGR compared to C-IUGR and EC (p<0.001). The placental weight (PW), renal weight (RW) and LW/BW, IW/BW, and RW/BW ratios did not change. IUGR fetuses had decreased kidney thickness (p<0.001) and decreased thickness of the intestinal mucosa and submucosa (p<0.05). Histological evaluation showed reduction of liver glycogen storage in fetuses with IUGR compared to C-IUGR and CE. the model described was efficient and caused symmetric fetal IUGR with decreased size of most organs, especially the liver, and changes in glycogen store

Evaluation of histological changes after tracheal occlusion at different gestational ages in a fetal rat model

OBJECTIVES: To evaluate the histological changes of tracheal cartilage and epithelium caused by tracheal occlusion at different gestational ages in a fetal rat model. METHODS: Rat fetuses were divided into two groups: a) External control, composed of non-operated rats, and b) Interventional group, composed of rats operated upon on gestational day 18.5 (term = 22 days), divided into triads: 1) Tracheal occlusion, 2) Internal control and 3) Sham (manipulated but not operated). Morphological data for body weight, total lung weight and total lung weight/body weight ratio were collected and measured on gestational days 19.5, 20.5 and 21.5. Tracheal samples were histologically processed, and epithelial, chondral and total tracheal thicknesses were measured on each gestational day. RESULTS: The tracheal occlusion group exhibited an increase in total lung weight/body weight ratio (

Temporal profile of intestinal tissue expression of intestinal fatty acid-binding protein in a rat model of necrotizing enterocolitis

OBJECTIVES: Necrotizing enterocolitis is a severe multifactorial intestinal disorder that primarily affects preterm newborns, causing 20-40% mortality and morbidity. Intestinal fatty acid-binding protein has been reported to be a biomarker for the detection of intestinal injuries. Our aim was to assess intestinal tissue injury and the molecular expression of intestinal fatty acid-binding protein over time in a necrotizing enterocolitis model. METHODS: A total of 144 Newborn rats were divided into two groups: 1) Control, which received breastfeeding (n=72) and 2) Necrotizing Enterocolitis, which received formula feeding and underwent hypoxia and hypothermia (n=72). A total of six time points of ischemia (2 times a day for 3 days; 12 pups for each time point) were examined. Samples were collected for analysis of body weight, morphological and histological characteristics, intestinal weight, intestinal weight/body weight ratio, injury grade, and intestinal fatty acid-binding protein levels. RESULTS: Body and intestinal weights were lower in the Necrotizing Enterocolitis group than in the Control group (

Corticosteroid effect upon intestinal and hepatic interleukin profile in a gastroschisis rat model

PURPOSE: To evaluate the effect of corticosteroids on intestinal and liver interleukin profile in an experimental model of gastroschisis in fetal rats. METHODS: Sprague-Dawley rats at 19.5 days of gestation had its fetuses operated for the creation of gastroschisis. Two groups of fetuses were studied with and without maternal administration of dexamethasone. Each group was composed of fetuses who underwent gastroschisis (G), control fetuses without manipulation (C) and sham fetuses (S). A dosage of the following interleukins was carried out in fetal intestinal and liver tissues: IL-1, IL-6, IL-10, tumor necrosis factor-alpha (TNF-&#945;) and interferon-gamma (IFN-&#947;). The differences between the groups and subgroups were tested by ANOVA with Tukey post-test, with significant values of p<0.05. RESULTS: Dexamethasone led to an increase in intestinal and liver IL-6 (p<0.05) and a decrease in intestinal TNF-&#945; (p<0.001) in fetuses with gastroschisis. CONCLUSION: Corticosteroids had an effect on the intestinal interleukin profile and a small effect on the liver interleukin profile due to immunological immaturity of the fetus, and also of fetuses with gastroschisis. The steroid action may not be exclusively anti-inflammatory, but also pro-inflammatory, varying with time of pregnancy

The role of gut-liver axis in the restriction of intrauterine growth in a model of experimental gastroschisis

PURPOSE: To evaluate the intrauterine growth restriction (IUGR) by the expression of IR-&#946;, IRS-1, IRS-2, IGF-IR&#946; and Ikappa&#946; in experimental model of gastroschisis. METHODS: Pregnant rats at 18.5 days of gestation were submitted to surgery to create experimental fetal gastroschisis (term = 22 days) were divided in three groups: gastroschisis (G), control (C) and sham (S). Fetuses were evaluated for body weight (BW), intestinal (IW), liver (LW) and their relations IW/BW and LW/BW. IR-&#946; and IGF-IR&#946; receptors, IRS-1 and IRS-2 substrates and Ikappa&#946; protein were analyzed by western blotting. RESULTS: BW was lower in G, the IW and IW / BW were greater than C and S (p<0.05) groups. The liver showed no differences between groups. In fetuses with gastroschisis, compared with control fetuses, the expression of IGF-IR&#946; (p<0.001) and Ikappa&#946; (p<0.001) increased in the liver and intestine, as well as IR-&#946; (p<0.001) which decreased in both. In contrast to the intestine, IRS-1 (p<0.001) increased in the liver and IRS-2 decreased (p<0.01). CONCLUSION: The axis of the intestine liver has an important role in inflammation, with consequent changes in the metabolic pathway of glucose can contribute to the IUGR in fetuses with gastroschisis

Effect of nitrofen in the final stages of development of the diaphragm muscle in rats

PURPOSE: To evaluate the expression of myosin in muscle fibers of the diaphragm in experimental congenital diaphragmatic hernia (CDH). METHODS: Fetuses of pregnant rats were divided into four groups: External Control (EC), composed of non-manipulated rats; Nitrofen, composed of pregnant rats that received 100 mg of nitrofen (2,4-dichloro-4'nitrodiphenyl ether) diluted in olive oil on gestational day (GD) 9.5, whose fetuses developed CDH (N+) or not (N-), and Olive Oil Placebo (OO), composed of pregnant rats that received the oil on the same GD. The fetuses were collected on GD 18.5, 19.5, 20.5 and 21.5 (term = 22 days). We obtained body weight (BW) and photographed the diaphragm area (DA), hernia area (HA) and subsequent calculated the HA/DA ratio in N+ group. Samples of Diaphragm muscle were processed for histological staining with H/E and immunohistochemistry (IHQ) for myosin.} RESULTS: The fetuses of N- and N+ groups had decreased BW and DA compared to EC and OO groups (p <0.001). HA was decreased on GD 18.5 compared to 21.5 (p <0.001) and the HA/DA ratio showed no difference. IHQ showed decreased expression of myosin in nitrofen groups. CONCLUSION: CDH induced by nitrofen model contributes to the understanding of muscularization in the formation of the diaphragm where the myosin expression is decreased

Evaluation of protection and treatment of fetal bowel using hydrogel (biomaterial) and S-nitrosoglutathione (GSNO) in the experimental model of gastroschisis

Orientador: Lourenço Sbragia NetoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: Gastrosquise é um defeito congênito da parede abdominal anterior no qual as alças intestinais ficam herniadas e em contato com o líquido amniótico (LA) cuja exposição crônica resulta em várias disfunções intestinais no período pós-natal. Para reduzir o efeito danoso desta exposição utilizou-se em modelo animal, dosagens diferentes de S-nitrosoglutationa (GSNO), doador de óxido nítrico (NO) e para a concentração mais diluída acrescentou-se o hidrogel de N-isopropilacrilamida (NIPAAm) copolimerizado com ácido acrílico (Aac) para cobrir as alças fetais expostas fetais afim de avaliar o tratamento com NO e a proteção oferecida pelo biomaterial. A gastrosquise foi induzida cirurgicamente em fetos de ratas com 18,5 dias de gestação. Os fetos foram separados em dez grupos: controle externo (CE), gastrosquise (G), controle interno (CI), Sham (S), gastrosquise + adesivo de fibrina - Beriplast® (GA), gastrosquise + adesivo de fibrina + hidrogel seco (GAH), gastrosquise + GSNO a 50 µM (GNO1), gastrosquise + GSNO a 5 µM (GNO2), gastrosquise + GSNO a 0,5 µM (GNO3), gastrosquise + GSNO a 0,05 µM (GNO4), gastrosquise + adesivo de fibrina + hidrogel seco + GSNO a 0,05 µM (GAHNO4). Com 21,5 dias de gestação, os fetos foram colhidos por cesárea e o hidrogel foi cuidadosamente removido. Ao grupo GNO1 não foi dada continuidade, pois a dosagem foi nociva aos animais. Dados de peso corporal e intestinal foram aferidos e algumas amostras do intestino foram fixadas para estudo histométrico e imunoistoquímico e outras congeladas para western blotting e quimioluminescência. Resultados das medidas morfológicas e histométricas, como peso, diâmetro, espessura das camadas e da parede intestinal, demostraram que o grau de proteção e tratamento das alças intestinais foi eficaz nos grupos GAH e GAHNO4, pois apresentaram valores significamente menores, assim como os grupos CE e CI e diferente dos grupos G, GA, GNO2, GNO3 e GNO4 que indicaram processo inflamatório. A expressão das enzimas nNOS, iNOS e eNOS por meio de western blotting e imunoistoquímica dimunuiu principalmente nos grupos GAH, GNO4 e GAHNO4 ficando iguais aos grupos CE e CI. A quantificação de nitrato e nitrito (NOx) no intestino e no LA por quimioluminescência nos grupos G, CI e S, mostrou que o NO se difunde do tecido intestinal para o LA, no grupo G e isso pode ser a causa para o aumento da expressão da enzima NOS. Sendo assim, a aplicação do hidrogel aderido pelo adesivo de fibrina mostrou servir como uma efetiva proteção das alças herniadas e o tratamento concomitante com GSNO a 0,05 ?M também ajudou na redução significante da inflamação na gastrosquiseAbstract: Gastroschisis is a congenital defect of the anterior abdominal wall in which the herniated bowel is in contact with the amniotic fluid (LA) whose chronic exposure results in several postnatal bowel dysfunction. To reduce the harmful effect of this exposure it was used in an animal model, different doses of S-nitrosoglutathione (GSNO), donor of nitric oxide (NO) and the more dilute concentration was added to the hydrogel of N-isopropylacrylamide (NIPAAm) copolymerized acrylic acid (Aac) to cover the exposed fetal handles in order to assess fetal treatment with NO and the protection offered by the biomaterial. Gastroschisis was surgically induced in fetuses of female Sprague-Dawley rats at 18.5 days of gestation. The fetuses were separated into ten groups: external control (CE), gastroschisis (G) internal control (CI), Sham (S), gastroschisis + fibrin adhesive - Beriplast® (GA), gastroschisis + fibrin adhesive + dry hydrogel (GAH), gastroschisis + 50 µM GSNO (GNO1), gastroschisis + 5 µM GSNO (GNO2), gastroschisis + 0.5 µM GSNO (GNO3), gastroschisis + 0.05 µM GSNO (GNO4), gastroschisis + fibrin adhesive + dry hydrogel + to 0.05 ?M GSNO (GAHNO4). On day 21.5 of gestation, fetuses were collected by cesarean section and the hydrogel was carefully removed. The group GNO1 was not given continuity, because the dosage was harmful to the animals. Data of body weight and intestinal samples were measured and some intestinal samples were fixed for immunohistochemical and histometric study and the others were frozen for western blotting and chemiluminescence. Results of morphological and histometric measures such as weight, diameter and thickness of the intestinal wall, showed that the degree of protection and treatment of bowel was effective in groups GAH and GAHNO4 because they showed significantly lower values, as well as groups CE and CI and different from groups G, GA, GNO2, GNO3 and GNO4 that indicated inflammatory process. The expression of nNO, iNOS and eNOS enzymes by western blotting and immunohistochemistry decreased especially in groups GAH, GNO4 and GAHNO4, getting the same results as the CE and CI groups. Quantification of nitrate and nitrite (NOx) by chemiluminescence in the bowel and LA of groups G, S and CI showed that NO diffused from the intestinal tissue to LA in the group G and this may be the cause for the increased expression of the NOS enzymes. Therefore, the application of hydrogel joined by fibrin adhesive showed an effective protection of the herniated bowel and concomitant treatment with GSNO at 0.05 ?M, also helped in significant reduction in inflammation in gastroschisisDoutoradoFisiopatologia CirúrgicaDoutor em Ciência