OBJECTIVETo investigate the relationship between -308 genotype polymorphism in the promoter region of the tumor necrosis factor alpha (TNFalpha) gene and asthenospermia in infertile men.

METHODSAllele-specific polymerase chain reaction (ASPCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were used to analyze the genotype at position -308 in the promoter region of the TNFalpha gene in 187 infertile male patients, who were divided into Groups A (asthenospermia, n = 60), B (oligoasthenozoospermia, n = 65) and C (infertile patients with normal sperm, n = 62). The levels of TNFalpha in the seminal plasma from these patients were measured by radioimmunoassay, and all the data were statistically analyzed by SPSS16.0.

RESULTSGroups A and B exhibited significant differences from C in the frequency of GA/AA at position 308 in the promoter region of the TNFalpha gene (21.67% and 26.15% versus 8.06%, P < 0.05). Spearman analysis showed a negative correlation between the GA + AA type of the TNFalpha-308 allele and the percentage of grade a + b sperm (r = -0.690, P < 0.05). The level of TNFalpha in the seminal plasma was significantly elevated in Groups A ([4.23 +/- 0.45] ng/ml) and B ([4.29 +/- 0.47] ng/ml) as compared with C ([4.03 +/- 0.66] ng/ml, P < 0.05), but with no significant differences between Groups A and B (P > 0.05). It was also significantly higher in the GA+AA ([4.61 +/- 0.29] ng/ml) than in the GGtype ([4.06 +/- 0.45] ng/ml, P < 0.05).

CONCLUSIONRegardless of sperm density, the frequently of TNFalpha-308 GA/AA is negatively correlated with the percentage of grade a + b sperm, which may be associated with the level of TNFalpha in the seminal plasma. Accordingly, anti-TNFalpha therapy might be effective for asthenospermia, and the measurement of the TNFalpha level in the seminal plasma can be an auxiliary diagnostic marker for male infertility.