Correlation Analysis Between Single Nucleotide Polymorphisms Of COMT Gene Or Serum Beta-endorphin Levels And Pain Thresholds Of Healthy Han And Uyghur In Xinjiang

Object:This study was conducted to investigate whether the COMT gene and?-endorphin levels,contribute to ethnic differences in pain sensitivity between Han and Uyghur.Methods:160 healthy subjects were enrolled in this study,with Han and Uyghur groups each consisting of80 participants.Subjects went through six pain threshold experiments,including electric pain-perception threshold(EPPT),electric pain-tolerance threshold(EPTT),blunt-pressure pain-perception threshold(BPPPT),blunt-pressure pain-tolerance threshold(BPPTT),acute-pressure pain-perception threshold(APPPT),and acute-pressure pain-tolerance threshold(APPTT).From venous blood,single nucleotide polymorphisms(rs6269,rs4633,rs4818,and rs4680)of COMT gene were genotyped,and serum?-endorphin levels were measured by using ELISA.Bivariate correlation analysis and multiple linear regression were used to identify the relationships between COMT genotypes or?-endorphin levels and different types of pain thresholds.Results:In terms of pain threshold,APPPT,BPPPT,BPPTT,and EPTT of Uyghur subjects were all lower than those of Han subjects(Z=-2.89,P=0.004l;Z=-9.40,P<0.001;t=9.44,P<0.001;Z=-3.76,P<0.001).In terms of serum?-endorphin levels,?-endorphin levels of Uyghur subjects were lower than those of Han subjects(Z=-7.18,P<0.001).In COMT rs4680 genotype distribution,the proportion of AA and AG alleles in Han subjects were lower than that in Uyghur subjects and the GG allele ratio of Han subjects was higher than that of Uyghur subjects(?~2=10.91,P=0.0061).In COMT rs4633 genotype distribution,the TT and CT allele ratio of Han subjects were lower than that of Uyghur subjects and the CC allele ratio of Han subjects was higher than that of Uyghur subjects(?~2=12.33,P=0.0021).?-endorphin levels did not correlate with COMT rs4680 or 4633 genotypes.In multiple linear regression,age,BMI,ethnicity,and COMT rs4680 genotype had statistically significant effects on EPTT(F=12.49,P<0.001,adjusted R~2=0.22).Gender,ethnicity,and?-END levels had statistically significant effects on BPPTT(F=46.24,P<0.001,adjusted R~2=0.46).Finally,age,ethnicity and gender had statistically significant effects on BPPPT(F=116.83,P<0.001,adjusted R~2=0.69).Statistical predictors for the lower pain-threshold performance included being young,Uyghur,female,having the low BMI,low serum?-endorphin level,and rs4680 AG allele.Conclusions:APPPT,BPPPT,BPPTT,and EPTT of healthy Han subjects were higher than that of healthy Uyghur subjects.The distribution of COMT rs4680 and rs4633 genotypes and serum?-endorphin levels were different between Uyghur and Han subjects.COMT rs4680 genotypes and serum?-endorphin levels contribute to ethnic difference in pain sensitivity between Han and Uyghur.