Experimental Research On Aberrant Methylation Of TNF-αGene And Its Protein Expression In Articular Cartilage Of Knee Osteoarthritis

ObjectivesTo investigate the role of Human TNF-α gene promoter hypomethylation in the occurrence and development of Knee osteoarthritis (OA).MethodsGeneral DNA were dealed with phenol chloroform extracting method. The hypomethylation of TNF-α promoter was detected by Methylation-specific PCR (MSP).TNF-α protein expression in joint cartilage cells were detected by Immunohistochemical method.37OA patients and13control patients were recruited from the in-patient of the second Xiangya hospital of Central South University.The results were analyzed by χ2or Fisher’s test and Spearman correlation analysis of SPSS17.0statistic analysis software.Results1. The positive percent of TNF-α promoter hypomethylation in healthy persons and OA patients were15.38%(2/13) and75.67%(28/37),respectively, Using χ2test, there was significantly different between the two groups(p<0.05).2. The positive percent of TNF-α protein in healthy persons and OA patients were23.08%(3/13) and78.37%(29/37) respectively. Using χ2test, the positive percent of TNF-α protein in OA patients was significantly higher than that in healthy persons(p<0.05).3. Hypomethylation of TNF-α gene and its protein expression had no significant relationship with sex and age.(P>0.05)4. Promoter hypomethylation and protein expression level of TNF-α gene showed significantly positive correlation.(r=0.467, P<0.01)ConclusionsTNF-α Promoter is hypomethlated in articular cartilage of knee OA patients. The hypomethylation increase the protein expression of TNF-α which might take a role in the occurrence and development of Knee OA.