This study was performed to observe the changes of glucose-related hormones and the morphological change including ultrastructure of the pancreatic islets in the male Otsuka Long-Evans Tokushima Fatty rat. Area under the curve (AUC) of glucose at the 30th (709 +/- 73 mg.h/dL) and at the 40th week (746 +/- 87 mg.h/ dL) of age were significantly higher than that at the 10th week (360 +/- 25 mg.h/ dL). AUC of insulin of the 10th week was 2.4 +/- 0.9 ng.h/mL, increased gradually to 10.8 +/- 8.3 ng.h/mL at the 30th week, and decreased to 1.8 +/- 1.2 ng.h/mL at the 40th week. The size of islet was increased at 20th week of age and the distribution of peripheral alpha cells and central beta cells at the 10th and 20th weeks was changed to a mixed pattern at the 40th week. On electron microscopic examination, beta cells at the 20th week showed many immature secretory granules, increased mitochondria, and hypertrophied Golgi complex and endoplasmic reticulum. At the 40th week, beta cell contained scanty intracellular organelles and secretory granules and apoptosis of acinar cell was observed. In conclusion, as diabetes progressed, increased secretion of insulin was accompanied by increases in size of islets and number of beta-cells in male OLETF rats showing obese type 2 diabetes. However, these compensatory changes could not overcome the requirement of insulin according to the continuous hyperglycemia after development of diabetes.
Animals ; Body Weight ; Diabetes Mellitus, Type 2/*metabolism/pathology ; Disease Models, Animal ; Glucagon/*metabolism ; Insulin/*metabolism ; Islets of Langerhans/*metabolism/pathology/ultrastructure ; Male ; Rats ; Rats, Inbred OLETF

OBJECTIVETo explore the synergistic protective effect of co-transplanted testicular cells expressing FasL and CsA on survival of islet allografts.

METHODSThe allogeneic islets and testicular cells were co-transplanted into the renal subcapsular space of the diabetic recipients with or without CsA after operation. Allografts survival period and the testicular cells or islets function were analyzed.

RESULTSThe mean survival period of control group was 4.6 +/- 1.1 days. When CsA was administered after transplantation, the mean survival period of islet allografts, (21.8 +/- 4.7) days, was significantly longer than that of control group (P < 0.01). When islets were co-transplanted together with 1 x 10(7) testicular cells (group A), a significant prolongation of graft survival was found (more than 57.5 +/- 4.0 days; P < 0.01 vs. control). But if 1 x 10(7) testicular cells expressing FasL were cultured with FasL-mAb for 30 minutes before co-transplantation (group B), the mean survival period of islet allografts (5.8 +/- 2.6 days), was similar to that in control group, but significantly shorter than that in group A (P < 0.01). When islets and 1 x 10(5) testicular cells were co-transplanted separately into the bilateral renal subcapsular space with CsA (group C), the survival of islet allografts was significantly prolonged in comparison with control group (more than 55.0 +/- 6.5 days; P < 0.01 vs. control), and similar to islets co-transplanted together with 1 x 10(7) testicular cells (group A). When islets were co-transplanted separately with 1 x 10(6) testicular cells without CsA (group D), the mean survival period (11.5 +/- 3.1 days) was shorter than that in group C, but prolonged in comparison to control group (P < 0.05).

CONCLUSIONThe co-transplanted testicular cells expressing FasL with administering CsA post-transplantation can jointly inhibit immune rejection of islet allografts by different mechanism and play a systemic and synergistic protective role to islet allografts.

Animals ; Cyclosporine ; therapeutic use ; Fas Ligand Protein ; Graft Survival ; Immunohistochemistry ; Insulin ; blood ; Islets of Langerhans ; pathology ; ultrastructure ; Islets of Langerhans Transplantation ; Male ; Membrane Glycoproteins ; analysis ; genetics ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar ; Sertoli Cells ; metabolism ; transplantation ; Transplantation, Homologous