Role of Human Umbilical Cord Blood-derived Stem Cells versus their Conditioned Medium on the Regeneration of Pancreatic Beta Cells in a Rat Model of Diabetes Mellitus

Abstract

Background: An efficient alternate source of mesenchymal stem cells (MSCs) was obtained from umbilical cord blood (UCB). Therefore, this work was designed to assess the role of human UCB-derived MSCs versus their conditioned medium (CM) on the regeneration of beta cells of the pancreas in a rat model of diabetes.Materials and Methods: Forty adult male Wistar rats were divided equally into 4 groups: Group I (control) and Group II (diabetic). Each rat was injected with a single dose of 35 mg/kg of streptozotocin (STZ) intraperitoneally. After being diabetics, they were left without treatment. Group III (UCB-MSCs treated) was injected with 1x106 cells/ml of UCB-MSCs once into the tail vein after confirmation of being diabetic. Group IV (CM treated) was injected intramuscularly with 0.5 ml of CM once per week after being diabetic. After 2 weeks and 4 weeks of being diabetic, the pancreas specimens from all groups were processed for H&E stain and immunohistochemically for anti-insulin and anti-caspase-3 antibodies. Results: The diabetic group showed distortion of the architecture of Langerhans islets, resulting in a decrease in the size of the islets and the appearance of many empty spaces within them. There was a significant reduction in body weight, serum insulin, serum C-peptide level, and insulin immunohistochemically stained positive cells. Moreover, a significant rise in blood glucose and in caspase-3 immunohistochemically stained positive cells was found. UCB-MSCs and CM-treated subgroups showed an obvious histological and biochemical improvement when compared to the diabetic group.Conclusion: Transplantation of UCB-MSCs was more efficient in the regeneration of pancreatic beta cells than injection of conditioned medium in the rat model of diabetes. However, CM could still prevent the degeneration of beta cells in islets of Langerhans, as indicated by its anti-inflammatory and anti-apoptotic effect