| Backgrounds:Adolescent idiopathic scoliosis(AIS)refers to deformity of the body caused by idiopathic scoliosis in adolescence,affecting the appearance,mental health and normal physical development of adolescent patients when it is mild.It probably affects cardiopulmonary function and thus threatening health and life of patients with AIS when severe.Currently,the pathogenesis of AIS is not yet fully clear.It is generally believed that AIS is associated with disease,hormone abnormalities,tissue abnormalities,genetic and other factors,with genetic factors predominating.Therefore,the study of genetic polymorphism on related genes in AIS is of great significance for the prevention and treatment of the disease.It has been reported that the polymorphism of 174 locus in IL-6 promoter region and 1672 locus in MMP3promoter region are associated with multiple diseases and is involved in the occurrence and development of a variety of bone tissue diseases.However,the current studies on the association between the polymorphism of two-loci and the presence of AIS in Chinese Han adolescents are rare and fail to reach consistent conclusions.Part one The correlation of IL-6,MMP3 polymorphism and the susceptibility and curative effect of AISObjective:To preliminarily investigate the relationship between single nucleotide(SNP)polymorphism of IL-6 promoter-174(rs1800795),MMP3 promoter-1672(rs3025058)and AIS susceptibility as well as effectiveness of surgical or brace treatment.The interaction between the two gene loci was analyzed.Methods:1.172 patients with AIS who were treated in Zhengzhou People's Hospital from January 2013 to June 2016 were selected as the case group and 210 subjects of the same age with normal spine who had physical examination in our hospital were collected as the control group.Patients in the case group were treated with surgical treatment or brace treatment,and were divided into two groups in accordance with the results before treatment and one-year after treatment:good efficacy group and poor efficacy group.2.The genotypes of IL-6-174 and MMP3-1672 in the control group were detected using polymerase chain reaction(PCR)and sequencing.The genotypes and difference in allele frequency distribution between the case group and the control group were compared.The correlation between polymorphism of two genes and susceptibility to and efficacy of AIS under different genetic patterns was analyzed with the use of Logistic regression analysis.The interaction between the two loci was analyzed with the use of generalized multi-factor interaction model.Results:1.The distribution of the loci of two genes in the case group and the control group was in line with the Hardy-Weinberg equilibrium.The distribution frequencies of genotypes GG,GC and CC in IL-6-174 locus were 69.8%(120/172),24.4%(42/172)and 5.8%(10/172)in the case group,respectively.The frequencies of those in the control group were 64.7%(136/210),28.6%(60/210)and 6.7%(14/210),respectively.There was no significant difference between the two groups(?~2=1.074,P=0.585).The distribution frequencies of genotypes 6A6A,6A5A and 5A5A in MMP3-1672 locus in the case group were 64.0%(110/172),29.7%(51/210)and6.3%(11/172),respectively.The distribution frequencies of those in the control group were 67.1%(141/210),28.1(59/210)and 4.8%(10/210),respectively.There was no significant difference between the two groups(?~2=0.685,P=0.710).Logistic regression analysis showed that genotype polymorphism of the two-locus had no correlation with AIS susceptibility in all genetic modes.2.In the case group,101 patients achieved good effectiveness one year after the treatment,,and the remaining 71 patients showed poor effectiveness.There was no significant difference in the genotype distribution of IL-6-174 between the two groups(?~2=4.760,P=0.093).However,there was significant difference in the distribution of allele frequency(?~2=4.680,P=0.031).The genotypes and allele frequency distribution of MMP3-1672 locus were not statistically different(?~2=1.098,P=0.580;?~2=1.072,P=0.300).Logistic regression analysis showed that the G allele of IL-6-174 was associated with a higher risk of adverse outcomes than the C allele[OR(95%CI)=3.226(0.1352-6.472),P=0.004],which has independent association with efficacy.Further analysis between subgroups under different treatment methods,the IL-6-174 genotypes only varied in different effect group when the treatment method was bracing.3.The results of GMDR showed that there was interaction between IL-6-174and MMP3-1672(P<0.05),but no significant correlation was found between the two variables generated by the two locus(P>0.05).Conclusions:1.There was no correlation between IL-6 promoter region-174 locus,MMP3promoter region-1672 locus and AIS susceptibility;2.There was no correlation between the polymorphism of MMP3-1672 and the efficacy of AIS,but there was independent association between the polymorphism of IL-6-174 locus and the efficacy of bracing treatment of AIS,with G allele indicating a higher risk of poor efficacy.3.There might be interaction between IL-6 promoter-174 locus and MMP3promoter region-1672 locus,but further research is needed to confirm.Part two Study on the correlation of IL-6 polymorphism and bone density of AIS patientsObjective:Based on the correlation between genotypes of IL-6-174,expression levels of IL-6,bone mineral density(BMD)parameters and bone metabolic parameters,we preliminarily investigated the mechanism of IL-6-174 polymorphism related to the efficacy of AIS.Methods:1.Bone mineral density(BMD)and bone mineral content(BMC)of femoral neck and lumbar L2~L4 were measured by dual-energy X-ray absorptiometry in 172patients with AIS.Fasting venous blood samples and interrupted urine samples were collected from all patients.Serum IL-6 levels and bone metabolism parameters such as bone alkaline phosphatase(BALP),bone gla-protein(BGP),tartrate-resistant acid phosphatase-5B(TRACP-5b),urinary calcium,urinary calcium/creatinine were measured by ELISA and automatic biochemical analyzer,respectively.2.The differences of parameters between patients receiving surgical treatment and patients receiving brace treatment were analyzed.Logistic regression analysis was used to analyze the correlation of the parameters on effectiveness.The levels of IL-6,differences of BMD parameters and bone metabolic parameters under different genotypes were analyzed.Pearson correlation analysis was used to analyze the correlation among the serum IL-6 level,parameters of bone mineral density,and parameters of bone metabolism.Results:1.For patients underwent surgical treatment,there was no significant difference in genotype distribution of IL-6-174 between the good efficacy group and the poor efficacy group(?~2=0.979,P=0.613).General case data,serum IL-6 level,parameters of BMD,bone metabolism index were also not significantly different(P>0.05);For patients underwent brace treatment,there was significant difference in the genotype distribution of IL-6-174 between the two groups(?~2=6.427,P=0.04).The efficacy of BMD and BMC of the lumbar spine in the good efficacy group were significantly higher than those in the poor efficacy group,while the serum IL-6 level,TRACP-5b,urinary Ca and urinary Ca/Cr in the good efficacy group were significantly lower(P<0.05)than those in the poor efficacy group,and no significant difference was found between the other indexes(P>0.05).2.Logistic regression analysis showed that allele in IL-6-174 locus,femoral neck BMD,lumbar spine BMD and TRACP-5b index were the independent influencing factors of efficacy for patients receiving brace treatment.3.The levels of IL-6 in different genotypes of IL-6-174 were significantly different(P<0.05).The femoral neck BMD,femoral neck BMC,vertebral BMD,vertebral BMC,TRACP-5b,urine Ca and urine Ca/Cr in different genotypes were statistically different.Pearson correlation analysis showed that there was a negative correlation between serum IL-6 level,bone metabolism indexes such as TRACP-5b,urinary Ca/Cr and BMD parameters(r<1,P<0.05).There was a positive correlation between TRACP-5b and urinary Ca/Cr index(r>1,P<0.05).Conclusions:1.There was no correlation between the genotype of IL-6-174 locus and the efficacy on AIS via surgical treatment.But there was independent association between the genotype of IL-6-174 locus and the efficacy on AIS via brace treatment.2.The mechanism of the correlation between polymorphism of IL-6-174 locus and efficacy of brace treatment is that polymorphism of IL-6-174 affects the expression of IL-6 and influences the bone resorption process in bone metabolism through IL-6 level,resulting in differences in BMD in patients with AIS,which affects the efficacy of brace treatment.Overall ConclusionsThe conclusions of this study are as follows:Polymorphism of both IL-6promoter-174 and MMP3 promoter-1672 has no correlation with AIS susceptibility.There is no correlation between MMP3-1672 locus and efficacies of surgical treatment and brace treatment of AIS.There is no relationship with between IL-6-174locus and the efficacy of surgical treatment of AIS,but polymorphism of IL-6-174locus is associated with the efficacy of brace treatment of AIS.The mechanism may be that the polymorphism of promoter region affects the expression level of IL-6,while IL-6 participates in the process of bone resorption in bone metabolism.Different bone resorption levels cause the accumulation of BMD differences in patients with AIS,thus affecting the effectiveness of brace treatment. |
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