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 d iabetes mellitus, and to find out if transplantation of islet cells is an e ffective treatment for the endothelial damage. Design: Experimental study. Setting: University hospital, Spain. Animals: 24 Wistar rats in 3 groups of each: control, diabetic and transpla nted. Interventions: Diabetes was induced in the diabetic and transplanted animal s by intravenous injection of streptozocin 45 mg/Kg. In the transplanted gr oup fresh pancreatic islet from syngeneic donor rats (1200-1500/receptor) w ere injected intraportally 16 weeks after the induction of diabetes. The ra ts were killed at 18 weeks. Excision of rings of thoracic aorta, which were contracted with 0(-5) M phenylephrine. Once the maximum contraction had be en 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 experime nt. Mean vasodilator response to acetylcholine as an indicator of recovery of endothelial function. Results: The mean (SD) vasodilatation in the control group differed signifi cantly 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 gro up (25.8 (3.6) g, p = 0.009). There was no significant difference between t he transplanted group and the control group (p = 0.33). Conclusion: In rats diabetes mellitus causes considerable endothelial damag e, which can be reversed by transplantation of pancreatic islets.