The Expression And Significances Of Interleukin-21, STAT3 And P-STAT3 In The Middle Ear Cholesteatoma And Granulation Tissue

Objective:Detection the expression levels of interleukin-21(IL-21),signal transduction and transcription activating factor 3(STAT3)and phosphorylated signal transduction and transcription activating factor 3(P-STAT3)in middle ear cholesteatoma,middle ear granulation tissue,and external auditory canal skin,respectively.Preliminary explore the roles of the three proteins in the pathogenesis of cholesteatoma and granulation tissue and the relationship among them.Methods:1.ELISA method was applied to detect the expression levels of IL–21 in 25 cases of cholesteatoma epithelial tissue and 15 cases of control group(external auditory canal skin of cholesteatoma patients).2.Immune histochemical method was applied to detect the expression of IL-21,STAT3 and P-STAT3 in 55 cases of experimental group(including 35 cases of cholesteatoma tissues and 20 cases of middle ear granulation tissues)and 20 cases of control group,respectively.The positive expression rates of IL-21,STAT3 and P-STAT3 were compared between cholesteatoma tissues and external auditory canal skin,between cholesteatoma matrix layer and epidermal layer in external auditory canal skin,between cholesteatoma perimatrix layer and granulation tissues,respectively.3.Relationships among the expression levels of IL-21,STAT3 and P-STAT3 in cholesteatoma were analysed,and correlational analyses were conducted among their expression levels and degrees of bone destruction in cholesteatoma.Results:1.The result of ELISA showed that no statistical difference was observed between the expression level of IL-21 in cholesteatoma and in external auditory canal skin(P=0.512).2.The results of immunohistochemical about IL-21 showed that:(1)Cholesteatoma tissue had positive expression of IL–21 as well as external auditory canal skin,but there were no statistical difference between the two group's(cholesteatoma 77.1%,control group 70.0%)positive expression rate(P>0.05),which was consistent with the result of ELISA;(2)No statistical difference was observed between the positive expression rate of IL-21 in cholesteatoma matrix layer(62.9%)and external auditory canal skin epidermal layer(65.0%)(P>0.05);(3)There was also no statistical difference between the positive expression rate of IL-21 in cholesteatoma perimatrix layer(71.4%)and granulation tissue(80.0%)(P>0.05).3.The results of immunohistochemical about STAT3 showed that:(1)Cholesteatoma tissue had positive expression of STAT3 as well as external auditory canal skin,and the positive expression rate of cholesteatoma(82.9%)was higher than external auditory canal skin(50.0%),and with statistical significance(P=0.010<0.05);(2)The positive expression rate of STAT3 in cholesteatoma matrix(77.1%)was higher than the epidermal layer in external auditory canal skin(45.0%),and with statistical significance(P=0.016<0.05);(3)No statistical difference was observed between the positive expression rate of STAT3 in cholesteatoma perimatrix layer(68.6%)and granulation tissue(75.0%)(P>0.05).4.The results of immunohistochemical about P-STAT3 showed that:(1)The positive expression rate of P-STAT3 in cholesteatoma(71.4%)was higher than external auditory canal skin(35.0%),with statistical significance(P=0.008<0.05);(2)The positive expression rate of P-STAT3 in cholesteatoma matrix layer(51.4%)was higher than external auditory canal skin epidermal layer(15.0%),with statistical significance(P=0.007 < 0.05);(3)No statistical difference was observed between the positive expression rate of P-STAT3 in cholesteatoma perimatrix layer(57.1%)and granulation tissue(70.0%)(P>0.05).5.Correlation analysis showed that:(1)No signifcant relationships were observed between the degrees of bone destruction and the expression levels of IL-21,STAT3,P-STAT3 in cholesteatoma(all P>0.05);(2)There was a statistically positive significant correlation between the expression of IL-21 and STAT3,IL-21 and P-STAT3,STAT3 and P-STAT3 in cholesteatoma(r=0.475,P=0.004;r=0.409,P=0.015;r=0.551,P=0.001),respectively.(3)There was also a statistically positive significant correlation between the expression of IL-21 and STAT3,IL-21 and P-STAT3,STAT3 and P-STAT3 in granulation tissue(r=0.577,P=0.008;r=0.491,P=0.028;r=0.630,P=0.003),respectively.Conclusions:1.IL-21/STAT3 signaling pathway may be active in the process of inflammation in cholesteatoma and granulomatous tissue.But no high significance was observed about the role of IL-21 to hyper-proliferation keratinocytes in cholesteatoma matrix layer.2.STAT3 signaling pathway may play an important role in the mechanisms of epithelial hyper-proliferation responsible for cholesteatoma.3.IL-21,STAT3 and P-STAT3 may not participate in the process of cholesteatoma bone destruction.