Study of the Reversibility of Endothelial Dysfunction in a Rat Model of Diabetes Mellitus: Experimental Treatment by Transplantation of Pancreatic Islets

Objective: To study the endothelial dysfunction induced in a rat model of diabetes mellitus, and to find out if transplantation of islet cells is an effective treatment for the endothelial damage. Design: Experimental study. Setting: University hospital, Spain. Animals: 24 Wistar rats in 3 groups of each: control, diabetic and transplanted. Interventions: Diabetes was induced in the diabetic and transplanted animals by intravenous injection of streptozocin 45 mg/ Kg. In the transplanted group fresh pancreatic islet from syngeneic donor rats (1200-1500/receptor) were injected intraportally 16 weeks after the induction of diabetes. The rats were killed at 18 weeks. Excision of rings of thoracic aorta, which were contracted with 0 -5 M phenylephrine. Once the maximum contraction had been reached relaxation was induced with 10 -5 M acetylcholine and then 10 -4 M independent nitroprusside endothelial vasodilator was added. Main outcome measures: Blood glucose concentrations throughout the experiment. Mean vasodilator response to acetylcholine as an indicator of recovery of endothelial function. Results: The mean (SD) vasodilatation in the control group differed significantly from that in the diabetic group (27.6 (3.9) g compared with 20.1 (3.9) g p = 0.002). The transplanted group also differed from the diabetic group (25.8 (3.6) g, p = 0.009). There was no significant difference between the transplanted group and the control group ( p = 0.33). Conclusion: In rats diabetes mellitus causes considerable endothelial damage, which can be reversed by transplantation of pancreatic islets.