Early ultrastructural changes in the pancreatic islets transplanted into the tongue of diabetic rats

ABSTRACT

Isolated pancreatic islets transplanted into the tongue of streptozotocin diabetic rats were used for studying early ultrastructural changes, 24 and 72 h post-transplantation. Adult inbred Lewis rats were used both as donors and recipients, the latter were rendered diabetic by a single dose [40 mg/kg] of streptozotocin. The islets were isolated by the collagenase digestion technique. Isolated islets [2500-3000] harvested from 8 rats were injected into the tongue of each recipient rat close to the sulcus terminalis [a total of 6 transplantation was done]. Small pieces [lmm[3]] of the tongue were removed after 24 and 72 h from the site of injection and processed for electron microscopic examination. Our observations 24 and 72 h post-transplantation showed active secretory endocrine cells, most of which belonged to the B cell type as characterised by the morphology of their secretory granules. Some non-B cell entities could also be discerned from the pleomorphism of their secretory granules. Most of these cells showed proliferating Golgi zones along with normal looking rough endoplasmic reticulum ribosomes and mitochondria. Some cells showed degranulation 72 h after transplantation. Functional evaluation showed slight improvement in the diabetic state of the recipient rats