Islet neogenesis-associated protein-related pentadecapeptide improves the function of allograft after islets...

To investigate the protective effects of a pentadecapeptide of islet neogenesis-associated protein (INGAP-PP) on transplanted islets function.

Islets were cultured in RPMI 1640 with or without INGAP-PP (10 μg/mL). After 24 h, the viability of the islets and glucose-stimulated insulin secretion (GSIS) were measured. The expression of genes B cell lymphoma/lewkmia2 (Bcl2) and protein kinase B (Akt) were detected by RT-PCR assay. Healthy rats transplanted with islets under the renal capsule were injected with INGAP-PP or saline in in the abdominal cavity. One week later, the expression of insulin nestin pancreatic (nestin) and duodenal homeobox 1 (Pdx1) and proliferating cell nuclear antigen (PCNA) in the transplanted islets were observed by immunohistochemistry. After that they were transplanted to the renal capsule of diabetic rats.

1. The amount of insulin released was increased in co-cultured group in concentration of 16.7 mmol/L glucose, which was (185.00±20.01 μU/mL) vs. (58.67±17.03 μU/mL). Gene expression of Bcl2 (0.61±0.22 vs. 0.50±0.21) and Akt (1.12±0.19 vs. 0.94±0.16) in the co-cultured group were increased compared with that of the control group. Islets viability in the co-cultured group (683.9±7.08) was higher than that of control group (547.9±8.02). The stimulating index (SI) of the co-cultured group was also higher than that of the control group. 2. The group of islets under the renal capsule which were co-cultured and injected with INGAP-PP had the more nestin expression in the islets.

The function of islet can be protected by the INGAP-PP, which will promote the viability, differentiation and regeneration of islet before transplantation. And it will be beneficial for the function of allograft after islets transplantation.