| Aims: To study the possibility that embryonic pancreatic anlagen transplanted to adult hosts can revascularise, grow and differentiate and the factors affecting the development. Because the transplantations of pancreas and islets are the main methods to cure diabetes mellitus, but the source of donor is limited. So it's necessary to find a new source for transplantation.Methods: We set up the model of pancreatic anlagen transplantation on the outbred SD rat and inbred Lewis rats respectively. The pancreas from embryonic day(E)15.5, E16.5, E17.5 and E18.5 SD rat embryos were implanted into the intra-peritoneal and sub-renal capsular site of healthy SD rats. By 2~3 weeks after implantation, the pancreatic anlagen in host rats were resected for measurement, histopathological and immunohistochemical examination. According to the result, we could conclude which embryonic age is the best for the transplantation.The pancreas from embryonic day 14.5 and 15.5 Lewis rat embryos were implanted into the intra-peritoneal and sub-renal capsular site of healthy Lewis rats respectively. By 3 weeks and 6 weeks after implantation, the pancreatic anlagen in host rats were resected for measurement, histopathological and immunohistochemical examination.Results: In the outbred SD rats transplanted groups, (1) By 3 weeks after implantation into sub renal-capsular site, acinar and ductal tissues were present in E15.5 pancreatic anlagen.βcells'(that stained positive for insulin) proliferation and concentration and minimal rejection were observed. However, we could see restricted development and moderate rejection on the E15.5 pancreatic anlagen implanted into intra-peritoneal site for 2.5 weeks. (2) By 2.5 weeks after implantation into sub renal-capsular site, E16.5 pancreatic anlagen underwent moderate rejection. (3) E17.5 and E18.5 pancreatic anlagen was severely rejected within 2.5 weeks of implantation into sub renal-capsular site, neither development nor proliferation ofβcells was present.In the inbred Lewis rats transplanted groups, (1) By 3 weeks after implantation into sub renal-capsular site, E14.5 and E15.5 pancreatic anlagen had enlarged 10~15 times. The acinar component for external secretion had differentiated. The proliferation of theβcells was obvious, and several islets that stained positive for insulin could be found. The area of positive stained endocrine islets is 53605.9±15153.8 um2 and 109024.1±31413.5um2 respectively. There are some new vessels around the tissue. (2) By 6 weeks after implantation into sub-renal capsular site, continued proliferation of the endocrine islets in E14.5 pancreatic anlagen could be observed while we couldn't see the continued proliferation on the E15.5 pancreatic anlagen. Fibrosis appeared in the exocrine component. It seemed that endocrine islets would separate from the exocrine component. (3) By 3 weeks after implantation into intra-peritoneal site, E15.5 pancreatic anlagen had enlarged.βcells proliferated and formed the islets. The area of positive stained endocrine islets is 20831.6±11480.1 um2. However, neither the size of the pancreatic anlagen nor the proliferation of theβcells was more obvious than that in the sub-renal capsular site.Conclusions: (1) The pancreatic anlagen of appropriated ages allografted into the nonimmunosuppressed outbred and inbred rats undergo revascularization, growth and differentiation. Implantation of the embryonic pancreas is followed by selective differentiation of islet compared with acinar components over 6 weeks. (2) E14.5 and E15.5 are the right embryonic age for the transplantation of pancreatic anlagen. (3) Contrasted to the anlagen transplanted into the intra-peritoneal site, the size of the anlagen transplanted into the sub-renal capsular site is bigger andβcells are more than the former.
|
PDF Full Text Request