A Study On The Relationship Between The RANK Protein Expression And RANK-RANKL Gene Polymorphism With Bone Metabolism In Postmenopausal Women With Type 2 Diabetes

Objective: The expression level of RANK protein and the polymorphism of RANK and RANKL gene loci in postmenopausal type 2 diabetes mellitus(T2DM)women in Shihezi area of Xinjiang were detected to explore the relationship between RANK protein expression and bone metabolism indexes and bone mineral density(BMD),so as to provide basis for the prevention and treatment of T2 DM with osteoporosis(OP)in postmenopausal women in Shihezi area.Methods: 1.A total of 200 postmenopausal women were enrolled and divided into 4 groups according to the 75 g oral glucose tolerance test(OGTT),T2 DM history and BMD: control group(group A),abnormal bone mass group(group B),T2 DM group(group C)and T2 DM + abnormal bone mass group(group D).2.Automatic biochemical analyzer detects Calcium(Ca)and other bone metabolism indicators,Lipid metabolism indicators such as triglycerides(TG),Fasting plasma glucose(FPG)and other glucose metabolism indexes.Dual-energy X-ray absorption method was used to measure BMD(L1-4 and femoral neck).High pressure liquid chromatography was used to measure hemoglobin A1c(Hb A1c).Enzyme linked immunosorbent method was used to measure RANK protein level and time of flight mass spectrometry was used to detect the genotype of RANK-RANKL site.3.SPSS 20.0 was used to analyze the data.The measurement data were expressed as x ±s,the comparison between groups was performed by ANOVA,the genotype distribution of loci was tested by Hardy-Weinberg equilibrium law,the genotype and allele frequency were analyzed by χ2 test,the correlation analysis between RANK protein level and clinical indicators was performed,and the influencing factors of BMD were analyzed by multiple linear regression.Receiver operating characteristic curve(ROC curve)was drawn to obtain the optimal concentration value of RANK protein expression level to diagnose OP.Results: 1.Compared with baseline data,there were differences in age and menopausal years between the groups,so analysis of covariance was used to compare biochemical indexes:(1)Bone metabolism indexes:no difference was found between the groups(P > 0.05);Comparison of BMD: BMD(L1-4 and femoral neck)levels were lower in group B and D than in group A(P < 0.01).(2)Glycine metabolism indexes:Compared with group A,FPG and Hb A1 c levels in group C and D were increased(P < 0.01).(3)The index of lipid metabolism: Compared with group A,the level of HDL in group C was increased(P < 0.01).2.Comparison of RANK protein expression: the expression level of RANK protein in group B,group C and group D were lower than group A(P < 0.05).3.The genotype distribution of RANK and RANKL loci complied with Hardy-Weinberg genetic equilibrium law(P > 0.05).4.Comparison of gene polymorphism:RANK gene rs78436403 locus was different between groups(P < 0.05).5.Comparison of gene mutations:(1)Bone metabolism index: RANK gene rs78326403 in B and C groups: ALP level of wild-type was higher than that of mutant type(P < 0.05);Comparison of BMD: RANKL gene rs9533155 showed lower BMD level in wild type femoral neck than in mutant type in group A and lower BMD level in mutant type than in wild type in group B(P < 0.05);RANKL gene rs2277438 showed lower wild-type L1-4 BMD in group A(P < 0.05).(2)Glucose metabolism index: RANK gene rs3018362 locus in C group,the level of wild-type Hb A1 c was higher than that of mutant type(P < 0.05);RANK gene rs78326403 in group A,the level of wild-type Hb A1 c was lower than that of mutant(P < 0.05).(3)The index of lipid metabolism: The level of wild-type HDL at rs9533155 of RANKL gene in group A was lower than that in mutant type(P <0.05);The level of wild-type LDL at rs2277438 of RANKL gene in group A was lower than that in mutant type(P < 0.05).6.Correlation analysis: RANK protein level was positively correlated with LDL,and negatively correlated with FPG and Hb A1 c.7.Multiple linear regression analysis of the risk factors of BMD: the prolongation of menopausal years and the reduction of BMI were the risk factors for the reduction of BMD L1-4.Decreased blood P level is a risk factor for reduced BMD of femoral neck.8.ROC curve of RANK protein expression level in diagnosis of OP: The optimal critical point for OP diagnosis was 0.388,the corresponding RANK protein concentration was 377.752 pg/m L,area under the curve(AUC)was 0.71,the sensitivity was 0.45 and the specificity was 0.94(P < 0.01).Conclusions: 1.RANK gene polymorphism and RANK-RANKL gene mutations in postmenopausal T2 DM women in Shihezi area resulted in decreased expression of soluble RANK protein,which was involved in the occurrence and development of OP.2.RANK protein level is of certain value in the diagnosis of OP in this population.3.RANK and RANKL gene mutations are involved in abnormal glucose and lipid metabolism in this population.