Esquistossomose mansonica em camundongo NOD/Uni (non-obese diabetic), modelo do diabetes Mellitus tipo 1

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

In this study we have demonstrated the effect of diabetes under the development of Schistosoma mansoni in diabetes-prone non-obese diabetic (NOD) mice, model of human diabetes type I. S. mansoni infection induces Th2 type cytokines at the liver of humans and mice. Recent reports have shown the evidence that Thl responses are detrimental and Th2 responses are protective against diabetes type I. In this study we took advantage of NOD mice, which has a Thl profile and has a limited survival after the expression of the diabetes. Female and male of NOD strain were infected with 10,25 and 50 cercariae from S. mansoni, BH strain, kept on Biomphalaria glabrata snails. SPF NOD mice were maintained in flexible PVC isolators with positive pressure. The test of diabetes Self-Stik @ resulting color changes using urine samples was performed and the last lecture (mg glucose/dL urine) was determinant for the establishment of the groups: no diabetic, diabetic male and female, diabetic pregnant. We monitored the survival until 7 weeks after infection or after the first detection of glycosuria and we compared these results with those obtained in a diabetic non-infected control group. In specific-pathogen free conditions, the NOD/Uni diabetic mice survive for 3-4 weeks after the first detection of glycosuria. Infected diabetic males presented longer survival (70%) when compared with the control no infected diabetic males (41,6%). The survival result in the infected diabetic females was 25% compared with 21 % in the no infected group. No mortality was registered in infected diabetic pregnant group. Seven weeks after infection, the animais were perfunded and adult worms prepared to the measurements. The length of worms was determined. The results were analysed according to the glucose leveI at the end of infection. Tukey s test was used to compare diabetic and no diabetic groups, with 5% significance leveI. Paraffm sections of liver and pancreas were cut at 5 J.UI1 and stained with hematoxylin-eosin. Hepatic granuloma measurements were determined using a computer system to take into account two perpendicular diameters crossing the center of isolated egg. Statistical analysis were performed to granuloma ellipse area using variance analysis and Tukey test was used to compare the length of the worms. Animais at the beginning of diabetes and normoglycaemic showed the same pattem to granuloma formation. Pregnant diabetic showed granuloma formation compared to the control no diabetic. The statistical analysis showed the influence of the diabetic status of the host and the leveI of glucose on the development of adult worm. When the diabetic female infected was pregnant , there were no differences in the length of the worms compared to the control no diabetic. Severe pancreatitis was involved mainly in diabetic females which presented extensive destruction of the pancreatic parenchyma 42 days after infection with 10 cercariae. The autoimmune process involved in diabetes concerning the helminth development is shown mean1y when glucose leveI in urine is high. The response Thl during accelerated and destructive diabetes and the shift to Th2 profile in schistosomiasis result on ThI/Th2 dichotomy which promotes a mechanism of regulation that inhibits or eliminates the granuloma formation in diabetic animais

ASSUNTO(S)

granuloma schistosoma mansoni diabetes

ACESSO AO ARTIGO

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