Regeneração do autoimplante esplênico em ratos: avaliação morfofuncional e imuno-histoquímica

Abstract

Given the importance of the spleen, it should be preserved whenever possible. If splenectomy is crucial, the only alternative to preserve spleen function is to perform a splenic auto-implantation. The aim of the present study was to assess the morphological regeneration of an auto-implanted spleen and to correlate it to its functional regeneration in a model of splenectomy combined with splenic auto-implantation in rats. Three-month old male Wistar rats (n=112) were randomly allocated into 16 groups (n=7). During 16 weeks, blood was collected to evaluate the presence of Howell-Jolly bodies (functional evaluation). These structures were found during the 15 first weeks, but decreased progressively starting at the 8th week, and were no longer found at the 16th week. In each specific week, after blood collection, rats were killed by anesthetic overdose and subjected to relaparotomy in order to retrieve the regenerated auto-implanted splenic tissue. The tissue was stained by hematoxylin and eosin and analyzed under the light microscope. Full morphological regeneration of the auto-implanted tissue was seen at the 8th week. Intense elastogenesis was detected by the Weigert resorcin-fuchsin stain during regeneration. Cell proliferation was increased starting at the 2nd week, and the highest density was seen at the 9th and 10th weeks (assessed by the immunohistochemistry of the proliferating cell nuclear antigen [PCNA]). Caspase-3 stain indicated higher apoptosis at the first weeks of experiment. The present data show that there is a morphological regeneration of the splenic auto-implant after 8 weeks of implantation, resulting in a morphologically healthy spleen, and it matches the initiation of the functional regeneration.