Effects Of Mesenchymal Stem Cells On AGEs/RAGE/NF-?B Signaling Pathway In Skin Tissue Of Newly Diagnosed Type 1 Diabetic Rats

Objective:NOD mice were treated with Human umbilical cord mesenchymal stem cells(hUCMSCs)to observe the effect of hUCMSCs on AGEs/RAGE/NF-?B signaling pathway in skin of NOD mice and explore its possibility of improving the"invisible damage"of diabetic skin tissue,and to provide valuable ideas and inspiration for the difficult problems such as difficulty in wound healing after clinical skin injury in diabetic patients.Methods:A total of 43 NOD mice were used,and after 9 weeks of feeding,they were divided into normal control group(NOD mice that were not infected after 9 weeks,n=12)and model group(NOD mice with diabetes after feeding,n=31).The model group was further divided into stem cell groups(on the 3rd day after the onset,hUCMSCs were injected into the tail vein by 1×10~6,n=11);the insulin group(after treatment,the appropriate amount of insulin glargine injection was given according to the condition,n=10);the blank control group(no intervention was taken after the onset,n=10).Each group of mice was recorded as day 0 on the day of onset,in which body weight was measured weekly and random blood glucose levels were measured.After 8 weeks,the mice were sacrificed and skin tissues were taken.Detect the following content and indicators:1.After HE staining,the skin structure was observed under optical microscope.2.The level of AGEs in skin tissue was detected by ELISA.3.Real-time qPCR method was used to detect the expression of RAGE and NF-?B p65 mRNA in skin tissues.4.Real-time qPCR method was used to detect the expression of IL-6 and TNF-?mRNA in skin tissues.Results:1.The mice in the normal control group had good living conditions and rich fur.The remaining three groups of mice gradually developed lazyness,hair loss,weight loss,and increased food intake after the onset.The mice in the blank control group performed particularly well and had severe hair loss.In the stem cells group and the insulin group,the blood glucose gradually decreased after 7 days of onset,and the blood glucose level was significantly lower than that in the blank control group(P<0.05),while the blood glucose level in the stem cell group was lower than that in the insulin group,and the difference was statistically significant(P<0.05).2.Under the microscope,the skin tissue was observed.The blank control group was compared with the normal control group.The latter had intact skin structure,clear epidermis,complete cell structure,and normal gaps.The dermal collagen was plump and arranged neatly.The blank control group had mouse skin.The structure of each layer is disordered,the epidermis lacks stratification,the overall thickness becomes thinner,the cells swell,the gap increases,and the collagen of the dermis becomes thin and the arrangement is sparse.The skin tissue structure of mice in insulin group was improved compared with the blank group.The skin tissue structure of mice in the stem cell group was significantly improved compared with the blank control group,and there was no significant difference between the control group and the normal control group.3.The levels of AGEs in the skin of the blank control group were significantly higher than those in the other three groups(P<0.05).The insulin group was higher than the stem cell group,and the difference was statistically significant(P<0.05).4.The mRNA expression of RAGE,NF-?B p65,IL-6 and TNF-?in the skin of the blank control group was significantly higher than that of the other three groups(P<0.05).The insulin group was higher than the stem cell group.Statistically significant(P<0.05).Conclusions:1.The application of hUCMSCs in the tail vein can significantly improve the hyperglycemia status of diabetic mice.2.Under the condition of metabolic disorders such as diabetes and high glucose,some microscopic pathological changes may occur in mouse skin tissue,and hUCMSCs can significantly improve this pathological change.3.Insulin and hUCMSCs can inhibit AGEs/RAGE/NF-?B signaling pathway to a certain extent,which can reduce the accumulation of AGEs and RAGE expression in skin tissue of diabetic mice,and reduce the expression of NF-?B and its downstream proinflammatory cytokines IL-6 and TNF-?,thereby improving the microenvironment of diabetic skin tissue,and have a certain protective effect on the“hidden damage”of diabetic skin tissue.