Studies On The Role Of PLC? In Schistosome Cercarial Dermatitis

Objective:The aim of this study was to explore the role and underlying mechanism of PLC? in cercarial dermatitis induced by Schistosoma japonicum(SJ)cercaria.Methods:Type I hypersensitivity(Type ?)and Type ? hypersensitivity(Type ?)were induced by percutaneous SJ cercaria infection in PLC? wild type(WT)and PLC? knock out(KO)mice.Skin biopsies of the inoculation site were done at different time points,3 mice in each time point of every gene type.The skin tissue was cut into three parts,they were analyzed in 3 aspects: histopathology,molecular biology and immunology.1.Histopathological analysis was performed on paraffin sections by HE(hematoxylin-eosin)staining.2.Total RNA was isolated from skin tissue and cDNA synthesis was performed.Then,mRNA levels of inflammation–associated cytokines were analyzed by qRT-PCR.3.Immunofluorescence staining was performed on frozen sections which were embedded by O.C.T.to detect the location and expression level of pro-inflammatory cytokines in skin tissue.Results:1.HE staining shows that there is no difference in skin inflammatory reaction between PLC? WT and KO mice in type ? cercarial dermatitis model.The thickness and number of inflammatory cells in the two genotype mice showed some trend.There is a increase of inflammatory cells in PLC? WT and KO mice at 12 h post infection(p.i.).However,no difference was observed in the total number of inflammatory cells between two genotype mice according to SPSS analysis(P>0.05).2.In type ?cercarial dermatitis model,the thickness of skin tissues and number of inflammatory cells in both PLC? WT and KO mice showed the some trend.The skin were becoming thicker after the infection,and the thickness were significantly suppressed in PLC? KO mice(t48h=5.317,P=0.000 t72h=10.162,P=0.000),besides it demonstrated significant difference when inferred to inflammatory cells at 48 h p.i.(t48h=2.888,P=0.020).3.mRNA levels of inflammation associated cytokines were analyzed by qRT-PCR.IL-1?,IL-1?,Cxcl-1 and Cxcl-2,which are mainly derived from fibroblast and keratinocyte,are decreased in PLC? KO mice after infection.(IL-1?: t12h=4.785,P=0.000;t24h=2.109,P=0.046;IL-1? t6h=3.187,P=0.004;t12h=5.049,P=0.000;Cxcl-1: t12h=4.858,P=0.000;Cxcl-2: t24h=7.957,P=0.000)However,there is a increase in the mRNA level of IL-23 and T cell derived cytokines,such like IL-4,IFNg,IL-17,which showed no difference in PLC? WT and KO mice(IL-23: t24h=-1.151,P=0.261;IL-4: t24h=0.496,P=0.625;IFNg: t24h=-0.035,P=0.973;IL-17: t24h=0.112,P=0.938).4.Immunofluorescence staining was performed on skin frozen sections to further evaluate the location of pro-inflammatory cytokines.The results showed that IL-1? was mainly located in both epidermis and dermis,IL-1? can be located in epidermis.Conclution:1.PLC? has less effect on acute cercarial dermatitis.2.PLC? plays a vital role in regulating delayed cercarial dermatitis.3.PLC? plays a crucial role in cercarial dermatitis inflammatory response by adjusting cytokines production derived from epidermal keratinocytes and dermal fibroblasts instead of immune cells in delayed cercarial dermatitis.