Decreasing loss of cryopreserved-thawed rat islets by coculture with Sertoli cells.

Abstract

Cryopreserved-thawed rat islets were cocultured with Sertoli cells to examine whether they could decrease the loss and improve islet function.
Islets and Sertoli cells were harvested from the pancreas and the testis of Sprague-Dawley rats, respectively. Cryopreserved, stored islets were thawed and divided into groups of coculture with Sertoli cells versus single cells. We measured islets recovery rate and function. Apoptotic-related proteins and gene expressions were detected by Western blot and reverse-transcriptase polymerase chain reaction. Soluble factors secreted by Sertoli cells in to the supernate were detected by enzyme-linked immunosorbent assay. We compared islet graft survival times in diabetic mice.
In contrast to the single culture controls, thawed islets cocultured with Sertoli cells exhibited improved morphology. Recovery rates and insulin secretion were significantly higher among coculture cells. Four soluble factors were detected in supernates from Sertoli cell cultures including transforming growth factor-β, insulin-like growth factor-1, epidermal growth factor, and basic fibroblast growth factor. Expression of proapoptotic Bax and caspase 3, 7 were down-regulated while that of antiapoptotic Bcl-2 was up-regulated. Cotransplantation with Sertoli cells significantly prolonged islet graft survival.
These results suggested that coculture with Sertoli cells significantly improved islet yields and function after thawing and depressed islet apoptosis.