The objective of the present study was to investigate the correlation between polymorphisms of the back-2 gene and osteoarthritis.
We enrolled 76 patients with osteoarthritis who were admitted to our hospital between February 2014 and February 2015 for treatment as the observation group, and 46 healthy subjects as the control group. The analysis of back-2 gene polymorphisms (rs28502) was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). mRNA expression of the different genotypes was measured with reverse transcriptase-polymerase chain reaction (RT-PCR), and the protein expression of back-2 of different genotypes was measured with enzyme-linked immunosorbent assay (ELISA) and Western blotting.
At locus 173 of the back-2 gene, there were a total of three genotypes, i.e. CC, CT, and TT. The frequencies of these genotypes in healthy subjects and osteoarthritis patients were 9.5%, 82.2%, 8.3% and 47.4%, 7.5%, 45.1%, respectively. There was a significant difference (p<0.05). However, the frequency of C/T in healthy older subjects and osteoarthritis patients was 50.6%, 49.4%, 51.15%, 48.85%, respectively, and there was no significant difference (p>0.05). RT-PCR showed no significant difference in mRNA expressions of the back-2 gene between the control group and observation group (p>0.05), although ELISA indicated that the protein expression of back-2 (12.3±0.36 μg/L) in osteoarthritis patients was significantly higher than in healthy subjects (1.52±0.18 μg/L) (p<0.05). Moreover, Western blotting analysis indicated that the protein expression of back-2 in osteoarthritis patients was significantly higher than in healthy subjects.
Genetic polymorphisms of back-2 are associated with the metabolic syndrome in older people, i.e. older people with the CC or TT genotypes may be at high risk for metabolic syndrome.