Anti-rejection Effect Of Triptolide On Islet Allografts In A Murine Model

ObjectiveTo establish a chemically induced type I diabetes mellitus model in mice.MethodsC57BL/6 mice were intrapreitoneally injected with different doses of streptozotocin (STZ). The peripheral blood glucose and body weight were monitored 2~6 days post-injection. The successful induction of diabetes was confirmed by measuring blood glucose greater than 20mmol/L. The mortality was recorded at the same time. ResulteSTZ were injected intrapreitoneally to the C57BL/6 mice as the following dosage: 150 mg/kg, 200 mg/kg and 225 mg/kg. The occurrence of diabetes was 0%, 60% and 100 % respectively 2 days post-injection, and 60%, 100% and 100% 5 ~ 6 days post-injection. Only one mouse died in the 225mg/kg STZ-injected group (mortality 5%). The body weight of mice lost when they became diabetic; moreover, the extent of weight loss was related to the dosage of STZ. The diabetic mice remained hyperglycemic despite of 2-week-treatment with insulin injection.ConlusionIntrapreitoneal injection of streptozotocin at a dose of 225mg/kg was a simple, safe and effective way to induce type I diabetes in murine model. ObjectiveTo establish a steady mice pancreatic islet isolation and transplantation model.MethodsBALB/c mice were used as donors. The donor pancreases were distended by collagenase type V solution via puncturation of common bile duct and followed by digestion at 37℃for 30 mins. The islets were purified by discontinued Ficoll gradient. The STZ induced C57BL/6 dibetic recipient were transplanted with 400 islets beneath the renal capsule. Blood glucose and body weight were mornitored thereafter. The successful engraftment was regarded as the blood glucose <10 mmol/L within 3 days post-transplantation. Islet-bearing-kidney was removed 7 days after islet transplantation, and blood glucose was monitored after nephrectomy. ResultThe BALB/c islets yield was 95±12(85~112) islets/pancreas on average. All C57BL/6 diabetic mice became normal glycemic (<10mmol/L) on post transplant day 1, and remained normal until day 11. The immediate drop of the body weight followed by a quick regain demonstrated the correction of the diabetic status. The hyperglycemia occurrence after removal of the islet-bearing-kidney confirmed the functional graft. ConclusionOur islet isolation method with collagenase type V digestion and discontinued Ficoll gradient purification produced good islet yield. Islet transplantation under the renal capsule could correct the hyperglycemia state effectively. ObjectiveTo investigate the anti-rejection effect of Triptolide on islet allografts in a murine model.MethodsBALB/c mice was used as islet donor. C57BL/6 mice were rendered diabetic by STZ injection, and transplanted with islets under the kidney capsule. The recipients were divided into two groups. The mice in the treatment group were given triptolide(50μg/kg)intraperitoneally daily in the first 5 days and then on alternate days until 14 days; meanwhile the mice in control group were given vehicles. Blood glucose and body weight were monitored. The grafts were defined as rejection when 2 consecutive reading of blood glucose >20mmol/L.ResultsThe median graft survival time of the triptolide treated group was 29.5 days (23 days~30 days), however, that of the control group was 14.0 days (13 days~16 days). The difference between the two groups is significant (P<0.0001). Conclusion Triptolide could prolong the islet allograft survival time in mice.