Objective To investigate the role of bone marrow mesenchymal stem cells derived from diabetic mice and their paracrine roles in inducing insulin resistance(IR).Methods The mouse model of diabetes mellitus was established,bone marrow mesenchymal stem cells(BMSC)were extracted and cultured,and the culture supernatant(M-BMSC-CS)was collected.(1)Cell experiment:HepG2 hepatocytes were divided into normal low-glycemic culture group[cultured with low-glycemic DMEM(5.55 mmol·L-1)],M-BMSC-CS experimental group(M-BMSC-CS 75 μL),and high-glycemic and high-lipid control group(given 25 mmol·L-1 high-glycemic DMEM+0.25 mmol·L-1 palmitic acid);(2)Animal experiments:Mice were divided into normal mice group(0.9％NaCl by intraperitoneal injection)and M-BMSC-CS-m group(M-BMSC-CS by intraperitoneal injection of normal mice(injection dose 0.2 mL/10 g)].Glucose intake was measured by glucose oxidase method.The fluorescence intensity of Glut2 protein was detected by immunofluorescence.The expression of insulin signaling pathway protein was detected by Western blot.Test oral glucose tolerance(OGTT)and insulin tolerance(ITT).Results The glucose intakes of the normal low-glucose culture group,the M-BMSC-CS experimental group and the high-glucose and high-lipid control group were(2.96±0.05),(1.64±0.28)and(1.42±0.32)mmol·L-1,respectively;the fluorescence expressions of glucose transporter 2(Glut2)were 53.21±2.70,30.95±3.39 and 34.96±7.60,respectively;the protein expression levels of phosphorylated insulin receptor substrate 1-ser307(p-IRS-1ser307)were 0.46±0.21,1.09±0.24 and 0.91±0.16,respectively;phosphorylated protein kinase(p-AKT)protein expression levels were 0.94±0.05,0.59±0.06 and 0.53±0.05;Glut2 protein expression levels were 1.08±0.14,0.58±0.14 and 0.62±0.09,respectively.The above indexes in M-BMSC-CS experimental group were statistically significant compared with those in normal low-glycemic culture group(all P＜0.05).Fasting blood glucose levels in the normal group and M-BMSC-CS-m group were(5.23±0.57)and(9.30±1.14)mmol·L-1;p-AKT protein expression level were 1.27±0.21 and 0.51±0.19;Glut2 protein expression level were 1.17±0.17 and 0.79±0.09,respectively.The above indexes in M-BMSC-CS-m group were significantly different from those in normal mouse group(P＜0.05).Conclusion BMSC culture supernatant from diabetic mice induced insulin resistance of normal HepG2 hepatocytes in vitro and normal mice in vivo.

Objective To investigate the relationship between the injury and ferroptosis of bone marrow mesenchymal stem cells(BMSCs)induced by high glucose and high fat.Methods BMSCs were divided into normal group(5.50 mmol·L-1 glucose)and high glucose and high fat(HGHF)group(25.00 mmol·L-1 glucose+0.25 mmol·L-1 palmitic acid).Assessment of cellular aging via β-galactosidase staining;enzyme linked immunosorbent assay(ELISA)were used to detect tumor necrosis factor-α(TNF-α),interleukin-10(IL-10)release levels;glutathione(GSH),malondialdehyde(MDA)and ferrous ion(Fe2+)detection kits were used to detect ferroptosis related indicators;Western blotting was used to detect the expression of ferroptosis related signaling pathway protein acyl-CoA synthetase long chain family member 4(ACS14)/arachidonate 15-lipoxygenase(ALOX15)/glutathione peroxidase 4(GPX4).Results The senescence rates of normal group HGHF group were(6.80±1.60)％and(13.00±1.58)％;the levels of TNF-α were(122.54±3.94)and(169.77±2.89)pg·mL-1;the levels of IL-10 were(155.16±3.97)and(105.15±7.30)pg·mL-1;GSH levels were 4.30±0.33 and 1.55±0.14;MDA levels were 2.94±0.10 and 5.84±0.10;Fe2+levels were 6.22±0.35 and 16.13±0.36;the relative expression levels of ACSL4 protein were 0.42±0.05 and 0.84±0.10;the relative ALOX15 protein were 0.61±0.25 and 1.06±0.11;the relative expression levels of GPX4 protein were 1.13±0.17 and 0.33±0.08,respectively.The above indexes in the HGHF group were significantly different from those in the normal group(all P＜0.05).Conclusion 25 mmol·L-1 glucose combined with 0.25 mmol·L-1 palmitic acid for 24 h can be used as a suitable condition to induce BMSCs injury.ferroptosis plays an important role in BMSCs injury induced by high glucose and high fat.