To set up an economic and effective method for islet isolation from rat, and thereby prove a laboratory protocol of animal model for cl inical islet transplantation. Methods Twenty-five adult male SD rats weighing 230-380 g were used as organ donor. In each of 5 repeated experiments, pancreatic islets of 5 animals were isolated by intraductal infusion of compound sodium chloride injection (CSCI), and subsequently, digested with low concentration (0.5 mg/mL)of collagenase V solution. Islet purification was performed by using a discontinuous density gradient centrifugation thatwas prepared with 27.0%, 23.0%, 20.5% and 11.0% of Ficoll 400. Islet yield and purity were determined by dithizon (DTZ)stain, and propidium iodide (PI)/fluorescein diacetate (FDA) double stain was used to check viabil ity of islets. The endocrine secretory function was assessed by insul in secretion in either low (2.8 mmol/L) or high (25.0 mmol/L) glucose incubation after 3 days of culture in RPMI1640 media. Results Average islet digestion time of 5 experiments was (13.8 ± 1.6) min. Before purification, average isolated number was (5 626 ± 422) islets, and the number was significantly reduced to (2 914 ± 485) islets after purification (P lt; 0.01). The average recovery rate was 51.6% ± 6.0%, and the average yield was (583 ± 97) islets/pancreas. The average purity and viabil ity of islets were 90.2% ± 3.4% and 81.6% ± 7.0%, respectively. After 3 days of culture, insul in secretion of the islets was (116.1 ± 17.4) EU/L in high glucose incubation, which was significantly higher than that of low glucose environment [(39.7 ± 7.5) EU/L, P lt; 0.01)]. The average insul in stimulation index was 3.0 ± 0.4. Conclusion The islet isolation with the CSCI solution and digestion with low concentration of collagenase V decrease experimental cost and also have a beneficial effect on islet recovery and their function.
【Abstract】ObjectiveTo investigate the value of volumetric interpolated breathhold examination (3DVIBE) MRI sequence in the diagnosis of functional islet cell tumors of the pancreas. MethodsDedicated MRI scan was performed for 3 patients suspected to have functional islet cell tumors of the pancreas on clinical and laboratory basis. The MRI scan protocol included routine axial T1W and T2W, coronal true fast imaging with steady state procession (TrueFISP) and MRCP, gadoliniumenhanced 3DVIBE dynamic triphasic acquisitions and enhanced 2D GRE T1W scan. The three phases images of 3DVIBE sequence were acquired at 15 s, 40 s and 65 s after injection of contrast agent, corresponding to the early arterial, late arterial and portal venous phase respectively. The imaging features were compared with surgical and pathological findings. ResultsThe triphasic images of 3DVIBE sequence depicted clearly the morphology of small functional islet cell tumors of the pancreas and reflected accurately the characteristics of tumor blood supply, while other MRI sequences might miss these small lesions. ConclusionThinslice and fast dynamic MRI sequence, as exemplified by 3DVIBE sequence, is very useful in the detection and characterization of pancreatic functional islet cell tumors.
Objective To summarize the feasibility and safety of the islet cells co-transplantation with bone marrow mesenchymal stem cells (BMSCs) in the treatment of diabetes. Methods The latest progress and new achievements of islet cells transplantation and BMSCs transplantation in treatment of diabetes in the world were analyzed and reviewed. Results At present, the pancreas transplantation and the islet cells transplantation were mainly treatments for diabetes, the pancreas transplantation had disadvantages of large trauma and high mortality; the islet cells transplantation was safe, but had disadvantages of strong rejection, and the survival time of islets cells were short which affected the treatment effect of diabetes. The BMSCs co-transplanted with the islet cells could prolong the survival time of islet cells and could alleviate the rejection in body, so the co-transplantation can be more effective in treatment of diabetes. Conclusion The BMSCs co-transplant with the islet cells could reduce the rejection in vivo, reduce the inflammation in vivo, prolong the survival time of islet cells, extend the time of normal glucose, which may become the new treatment method for the diabetes.
ObjectiveTo investigate whether transplantation of islet cells combined with bone marrow mesenchymal stem cell (BMSCs) of the pancreatic subcapsular promoting revascularization of pancreatic islets in rats, so as to reduce the loss of islet cells after transplantation and improve the success rate of islet cell transplantation. MethodsThe model of diabetic rat was established. The BMSCs and islet cells were cultured and identified, then the simple islet cells, simple BMSCs, and combination of islet cells and BMSCs were injected into the pancreatic subcapsular of the islet cell group, BMSCs group, and combination group, respectively. In addition, the same amount of normal saline was injected into the same site as the control group. There were 10 rats in each group. The changes of blood glucose and serum insulin in different time point were detected in each group. The mRNA expressions of angiogenesis factors such as hypoxia inducible factor-1α (HIF-1α), stromal cell derived factor 1α (SDF1α), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor 2 (FGF2) were determined by real-time quantitative PCR. Results① The blood glucose levels of the islet cell group and combination group were lower than those of the control group and the BMSCs group within 15 d after surgery (P<0.05) and decreased to the normal level, which of the combination group could still maintain the normal level until on day 29 (P<0.05), but which of the islet cell group began to increase on day 15 after surgery and was similar to that in the BMSCs group (P>0.05). ② Compared with the control group and the BMSCs group, the insulin levels were higher in the islet cell group and combination group on day 1, 3, 7, 15, and 29 after surgery (P<0.05), especially in the combination group. ③ The expression levels of HIF-1α, SDF1α, VEGF, and FGF2 mRNAs in the combination group were higher than those the other three groups, and the differences were statistically significant (P<0.05). ConclusionsIslet cell transplantation of pancreatic subcapsular could decrease blood glucose level in diabetic rats. Hypoglycemic effect of single islet cell transplantation gradually weakens on day 15 d after surgery. After BMSCs combined with islet cells transplantation, the glycemic effect of rat is stable for a longer time. Expressions of angiogenesis factors of BMSCs combined with islet cells transplantation rat are high, which combined with pathological sections suggests that BMSCs could promote vascular recanalization of islet transplantation.