Protective Effects Of IPS To Islet Injury In Type ⅠDiabetes Mice

According to the World Health Organization,5%deaths each year in the worldwere caused by diabetes mellitus （DM）, and the number of deaths is estimated todouble between2005and2030, Obviously, DM is a major burden to societies andhealth systems. In most cases, DM-1is due to autoimmune destruction ofinsulin-producing pancreatic β-cells. The loss of glycemic control in diabetic patientsleads to complications of the microvasculature （retinopathy, nephropathy andandneuropathy） and macrovasculature （cardiovascular, cerebrovascular and peripheralvascular disease）[31].Administration of exogenous insulin could control hyperglycemia to some extentin DM-1patients. However, the control of glucose level is usually imperfect and maybe accompanied by a dangerous state of hypoglycemia. Therefore, administration ofexogenous insulin, albeit an effective treatment, is not a cure. Success in the field ofislet transplantation makes it possible to achieve adequate glycemic control throughcell-replacement therapy[2]. However, efforts at human islet transplantation haveencountered obstacles. First, the supply of donors cannot meet the need fortransplantation purposes. Second, immune system-mediated disease may recur aftertransplantation through various mechanisms, including graft rejection andautoimmune response[4].Induced pluripotent stem cells （iPSCs） have the ability to differentiate intovarious cell types of the body, representing a perfect source for cell-replacementtherapy in DM-1. Hence, there is a need to optimize the differentiation protocols togenerate fully glucose-responsive and mature cells[8]. In addition, the use of iPSCsmakes it possible to generate patient-specific disease models that could further ourunderstanding about the underlying cause of autoimmune DM. It may become animportant tool in the search for new treatments.Objective: To identify the protective effect of iPSCs on injured pancreatic isletsin DM-1and the influence of Itgβ1on the protective effect, and observe how the dosage andtime of the iPSCs injection affect the protective effect.Methods: A DM-1mouse mice model was prepared by intraperitoneal injectionof STZ. The second day after the construction of the DM-1model, iPSCs at2.4×10⁴per20g plus weight of the mice everyday were intravenously injected into the mice ata3-day interval. The experiment was conducted in three groups: PBS group, MEFsgroup and iPSCs group. The protective effect of iPSCS on pancreatic islet injury InDM-1mice was observed by detecting the fasting plasma glucose （FPG） andcalculating the pancreatic islets area ratio of the model mice at a3-day inrerval.On the first day after construction of the model,6×10⁴iPSCs per20g plus weightof the mice were administered twice daily and2.4×10⁴iPSCs per20g wereadministered three times daily via the caudal vein. FPG was detected at a3-dayinterval, and the pancreatic islets area ratio and survival rate of the modeled micewere calculated to observe how the various doses of injection affected the protectiveeffect of iPSCs on pancreatic islet injury in DM-1. Then iPSCs injection in the caudalvein was given on the1stand2ndday after construction of the the model. FPG wasdetected, and the pancreatic islets area ratio and survival rate of the modeled micewere calculated to observe the protective effect of iPSCs on pancreatic islets injury inDM-1.Results: On the2nd day of moedle construction,2.4×10⁴iPS cells per20g plusweight of the mice each time were given to the mice through caudal vein injectionthree times continuously. FPG was26.8mmol/Le in PBS group,24.87±2.02mmol/Lin iPSCs+Itgβ1group, and20.1±3.82mmol/L in MEF group at24th day afteradministration of the defined amount of caudal vein injection of iPSCs at thedesignated time, indicating that iPSCs had a certain hypoglycemic effect. FPG iniPSCs+Itgβ1group was14.65±3.2mmol/L, showing a more hypoglycemic effect ascompared with the other three groups. At the same time, the pancreatic islet area ratiowas0.07±0.002in PBS group,0.088±0.004in iPSCs+Itgβ1group,0.106±0.003inMEF group, and0.137±0.009in iPSCs group. the pancreatic islet area increased tothe certain degree in MEF group.The increase was more obvious in iPSCs group as compared with the other three groups.On the1stday of model construction,6×104iPS cells per20g plus weight of themice were given to the mice through caudal vein injection and twice altogether. It wasfound at18days that FPG was21.2±3.49mmol/L in iPSCs group,16.7±3.15mmol/L in MEFgroup group, and16.9±8.47mmol/L in PBS group. Meanwhile, the figurewas12.0±3.11mmol/L in iPSCs Itgβ1group, showing a more obvious hypoglycemiceffect, as compared with the other three groups.The pancreatic islet area ratio was0.073±0.006in iPSCs group,0.07±0.003in MEF group, and0.044±0.006in PBSgroup, versus0.11±0.006in iPSCs Itgβ1group, showing that the pancreatic islet arearatio increased more obviously as compared with the other three groups.But thesurvival rate is low.On the1stday after model construction,2.4×104iPS cells per20g plus weight ofthe mice were given to the mice through caudal vein injection three times. At day18,FPG was20.1±4mmol/L in iPSCs group,19.96±9.59mmol/L in iPSCs+Itgβ1group,6.55±6.58mmol/L in MEF group, and11.84±7.97mmol/L in iPSCs group. There isshowing a certain hypoglycemic effect in MEF group, There is a more hypoglycemiceffect in iPSCs group as compared with the other three groups. The pancreatic isletsarea ratio was not statistically analyzed in iPS and MEF group, for the mortality ratewas high in these two groups.Conclusions: On the2nd day of moedle construction,2.4×10⁴iPS cells per20gplus weight of the mice each time were given to the mice through caudal veininjection three times continuously. At day24, FPM level in ther DM-1mice wasreduced effectively. The pancreatic islet injury may have been repaired throughcertain mechanism and the islet cell proliferation may have been promoted. MEFcells showed a certain protective effect on the pancreatic islets injury of DM-1mice.On the1^st day of model construction,6×10⁴iPS cells per20g plus weight of themice each time were given to the mice through caudal vein injection and twicealtogether. The results demonstrated that FPG of the DM-1mice was not reducedsignificantly, the protective effect against pancreatic islet injury was not obvious, and the survival rate was low. It cannot be used in the treatment of DM-1.