The Expression Of High Mobility Group Box Protein B1 In The Skin Of Atopic Dermatitis Mice And The Protection Mechanism Of Ethyl Pyruvate

Aim:To construct a mouse model of atopic dermatitis in BALB/c mice,detect and analyze the expression of HMGB1 in the lesion area of the mouse’s back,and investigate the effects of HMGB1,RAGE,ToLL receptor and NF-κBp65 pathway on the pathogenesis of AD,and explore the effects of ethyl pyruvate.The protective mechanism of skin lesions in atopic dermatitis.Methods:In this study,40 BLAB/c female mice of SPF grade with 6-8 weeks old and about 16-20g were selected and randomly divided into such 4 groups as AD group(AD group,n=10)and normal control group(C group,n=10)and Ringer group(Ringer group,n=10)and EP treatment groups(EP group,n=10).All mice adapted to the environment for one week.In the AD group,the mice in the AD group were intraperitoneally injected with 0.1%OVA solution on the first day,the eighth day,and the fifteenth day of the experiment.On the 21st day of the experi:ment,the 4 groups mice were removed back hair(squre:8cm2)by 8%sodium sulfide amylum solution.On the 27th day,3M tapes were repeatedly pasted on the hair removal site 8 times.On the 28th to the 42nd day,2 cm x 2 cm gauze was infiltrated with a 0.1%OVA solution and applied to the mouse’s dorsal hair removal area for a total of three weeks.The normal control group was intraperitoneally injected with an aluminum hydroxide gel three times,and the PBS solution was applied on the 28th to the 42th day.Each injection and the application time was the same as that of the AD group.The EP treatment group was in the same manner as the AD group for the first 42 days,and was given an intraperitoneal injection of 100 mg/kg ethyl pyruvate solution on the 43rd day.The injection was continued once a day for 7 days.The Ringer’s group was modeled with the AD group 42 days before and the compound sodium chloride solution was given intraperitoneally on the 43rd day.The injection time and frequency were the same as above.At the end of the 49th day of modeling,the number of scratches in the four groups of mice was observed within 10 minutes,and inflammation scores were performed according to the degree of severity of the lesions.Four groups of mice were anesthetized with ether and the blood was collected from the eyeball.After standing for 30 minutes at room temperature,the supernatant was centrifuged to detect the total serum IgE and TNF-α concentrations in the four groups of mice.Four groups of mice were recorded for body weight,spleen weight,and spleen index.The HMGB1 protein-related protein was detected and HE staining was performed on the dermis lesions.Results:1.The score of skin inflammation in mice was significantly higher in the AD and the Ringer’s skin than in the normal control and EP treatment groups(P<0.05).2.As a result of spleen index and scratching times,the spleen index of AD group and Ringer group was higher than that of normal control group and EP treatment group(P<0.05).The number of scratches in the AD group and the Ringer group was higher than that of the normal control group and the EP treatment group(P<0.05).3.Histopathological examination results:The back skin of normal control mice was not damaged,and no abnormal structural changes were observed under the microscope.In the AD group,different degrees of thickening of the epidermis and dermis were observed.The dermal papillary layer was prolonged and a large number of inflammatory cells infiltrated.In the EP treatment group,the thickness of the epidermis and the dermis were all thin,and the infiltration of lymphocytes and other inflammatory cells was reduced.Western Blot detection:The expression of HMGB1,TLR4,RAGE and NF-κBp65 in AD group and Ringer group was significantly higher than that in normal control group and EP treatment group(P<0.05).5.ELISA results:The total IgE concentration in the serum of AD,Ringer,and EP groups was higher than that of the normal control group(P<0.05).The levels of serum TNF-α in AD and Ringer’s mice were higher than those in normal control and EP treatment groups(P<0.05).Conclusion:1.The degree of skin inflammation in the AD mouse model was positively correlated with the expression of HMGB1,TLR4,RAGE,and NF-κBp65 in the skin tissue.Ethyl pyruvate could reduce the expression of HMGB1 and its pathway and relieve the skin inflammation of AD mice.2.The degree of skin inflammation in AD mouse model was positively correlated with the serum TNF-α expression.Ethyl pyruvate can reduce the expression of cytokines and relieve the skin inflammation of AD mice.3.Damage-associated molecuLar pattern of HMGB1 protein is associated with pathogenesis,and its abnormal changes affect the severity of AD.