Study Of CXCR1/2 Antagonism With G31P In Mouse Model Of Atopic Dermatitis

Objectives: To study the function of CXCR1/2 antagonism with G31 P in the mice model of atopic dermatitis by local subcutaneous injection.Method:1.Animal Model: A total of 60 BALB/C mice were randomly divided into control,AD,G31 P groups(n=20 each).The mice model of atopic dermatitis was established by sensitization with ovalbumin(OVA)through the skin.The AD group and G31 P group were sensitized with OVA(100?l,1 ?g/?l)to a sterile patch.The patch was placed for a1-week period and then removed.Two weeks later,an identical patch were reapplied to the same skin site,repeated twice.The control group was injected with the same amount of saline.The mouse in G31 P group was local subcutaneous injection with CXCR1/2antagonism with G31 P 20?l(0.25?g/?l).2.Collect samples:Mouse were put to death after 24 h when sensitization or treatment finish.Collected the abdominal skin of sensitization.3.Detective method: ? Changes in skin tissue were observed.? Pathological changes in skin tissue were detected by HE.?The skin homogenate interleukin-4(IL-4)and interleukin-8(IL-8)were measured by enzyme linked immunosorbent assay(ELISA).? The m RNA of interleukin-4(IL-4),interleukin-8(IL-8),interleukin-6(IL-6)and interleukin-10(IL-10)in skin tissues were detected by fluorescent real timequantitative polymerase chain reaction(RT-PCR).?The protein expression of NF-?B in mouse skin tissues was detected by western blot and immunohistochemistry.?The protein expression of GRO-? in mouse skin tissues was detected by immunohistochemistry.? The activity of neutrophils in skin homogenate were measured by myeloperoxidase(MPO).Result:1.The changes of skin tissues in AD group were consistent with typical pathological manifestation of AD.The mouse of AD group scratched obviously and had erythema,scales in the local skin.The mouse of control no obvious scratched and the skin were smooth.There were no pathological damage in the control group.When compared with the AD group,the degree of skin pathological damage in the G31 P group were significantly reduced.So G31 P can inhibit OVA induced atopic dermatitis caused by local lesion in the mouse and have the effect of the adjustment to improve AD.2.The skin of AD group thicken obviously and have many inflammatory cell infiltration.When compared with the AD group,the degree of skin pathological damage in the G31 P group were significantly reduced.There were no pathological damage in the control group.3.The skin homogenate levels of IL-4,IL-8 in the G31 P [(10.76 ± 5.6,7.69 ±2.19,ng/L)] were significantly lower than those in AD group [(27.12 ± 6.3,16.69 ±2.36,ng/L)],but still higher than those in the control group [(4.18 ± 2.15,3.04 ±1.18,ng/L)](all P?0.01).4.The expression levels of m RNA of IL-4,IL-8,IL-6,IL-10 were significantly lower in the G31 P group than those in AD group(all P ? 0.05),but still remarkable as compared with the control group.5.The protein expression of NF-?B in mouse skin tissues was detected by western blot and immunohistochemistry.Compared with AD group the expression level of protein of NF-?B was significantly lower in the G31 P group,but still higher than the control group(all P?0.05).6.Compared with AD group,the expression level of GRO-? was significantly lower in the G31 P group.In the control group,GRO-expression was almost not expressed.7.The activity of MPO in the AD group [(34.69 ± 6.3,U/g)] was significantly higher than that in the control group [(4.18± 2.15,3.04± 1.18,ng/L)].The activity of MPO in G31 P group [(20.98±8.61,U/g)] was lower than that in AD group(all P?0.01).Conclusions:1.The expression of IL-8 in the skin of AD group was increased significantly.So IL-8 may play an important role on atopic dermatitis.2.Treatment with CXCR1/2 antagonism with G31 P by local subcutaneous injection could relieve the inflammation in the skin,decrease the levels of IL-4,IL-8 in skin homogenate and inhibit the expression levels of some inflammatory cytokines in local skin tissues.G31 P can also inhibit the activity of MPO in skin homogenate.Thus it plays an important role in the treatment of atopic dermatitis.