Study On Relationship Between Polymorphisms Of Estrogen α Receptor Gene Or Vitamin D Receptor Gene And Female Bone Mineral Density

Objective: Osteoporosis is characterized by a decrease in bone mass as well as a deterioration of the bone architecture resulting in an increased risk of fracture. With the increasing life expectancy all the country, osteoporosis is a major and growing health problem worldwide. Low bone mineral density (BMD) is a major risk factor for development of osteoporosis; increasing evidence suggests that attainment and maintenance of peak bone mass as well as bone turnover and bone loss have strong genetic determinants. Some loci, such as the vitamin D and estrogen receptor genes, as well as the collagen type Iα1 locus, are promising genetic determinants of bone mass. The genotype study of osteoporosis could evaluate the danger of osteoporosis fracture. If we separate certain kinds of gene to predict the lower BMD, we can have an effective therapy to these people. We investigated the possible relationship between polymorphisms of estrogen α receptor (ERα) gene or vitamin D receptor gene and bone mineral density (BMD) in women.Methods: Forty-third young healthy women andseventy-eight postmenopausal women enrolled into the study. None had a history of bone disease, illness or drug use that might affect bone turnover. Firstly, BMD of lumbar spine and femoral neck, ward and troch anteric areas were measured by dual energy X-ray absorption. Secondly, the genotypes of estrogen α receptor and vitamin D receptor were analyzed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). DNA was isolated from whole blood using fast methods. VDR and ERαprimers were used to the polymerase chain reaction (PCR) respectively. Then, the PCR products of VDR or ERαwere digested with restriction endonuclease respectively. Instantly, the products of endonuclease were visualized and recorded under EYE II analyzed instrument. Thirdly, osteocalcin (BGP) was measured by radioimmunoassay. The association between the genotypes of ERαand VDR and BMD or BGP was analyzed separately. The experimented data was demon stated in x±s deviation. The analysis of variance and t test were used to the significance test by spss 10.0 for windows software,α=0.05.Results: The genotypes Chinese people are PP 19.0%,Pp 41.3%,pp 39.7%；XX 7.4%,Xx 46.3%,xx 46.3%；BB 1.7%,Bb 10.7%,bb 87.6% respectively. And the genotypes of p,x and b are more than that of P,X and B in china. There was significant relationship between RFLP by PvuII or XbaI and BMD of lumbar spine (L2-L4) (p<0.01),and BMD values of femoral neck and troch antericwere Bb>bb (p<0.05) in 78 post menopausal women. In young healthy women, women with PP genotype have lower Ward's bone mass comparing those with Pp and pp ones (p<0.01). However, there was no significant between RFLP by XbaⅠand BMD in 43 young women . The BMD at Ward of genotype PPXx were significantly lower than those of other genotypes (p<0.05). The young women of genotype bb have lower BMD of Ward and femoral neck than those of BB and Bb (p<0.05). There was no difference between all kinds of genotypes and osteocalcin (BGP) in young or postmenopausal women (p>0.05).Conclusion: In the PPxx of genotype, BMD of lumbar spine were significantly lower than those in other genotypes. This result indicated that p and x allele may have some protective effects on lumbar spine bone mass. The genotype PPXx might indicate a lower BMD at Ward in young women .In this genotype in postmenopausal women and young women is sharply different from that of reports in western countries, as well as in China. The results suggested that there was association between ERαor VDR genotypes and BMD in Chinese women.