Male infertility is a factor in 50% of cases but no cause can be diagnosed in approximately 25% of infertile males. This is termed ‘idiopathic infertility’ and is thought to be linked to reduced antioxidant defense. The present study aimed to find a possible relationship between reducing antioxidant capacity, malondialdehyde (MDA) formation, and the compensatory antioxidant system of the neutrophile gelatinase associated lipocaline (NGAL) level and the standard semen parameters in idiopathic infertility. Thirty five Algerian soldiers including fertile men (n=8) and infertile men (n=27) who were selected for the heat stress and extreme physical exercises at least for 2 years in desert military units. The oxidative stress (OS) balance, total antioxidant capacity (TAC) versus MDA, was evaluated by fluoremetric methods either in semen and plasma samples. The plasmatic NGAL was measured by immunofluoremetric assay. Standard evaluation of seminogram was carried according to WHO guidelines. In semen, although MDA was significantly higher (p=0.000) while TAC were significantly lower (p=0.003) in infertile men than fertile men, no correlation was found between standard sperm parameters and MDA or TAC. In spite of the significant difference of plasma TAC between the two groups (p=0.000), no difference among them for MDA was detected (p=0.411). The semen TAC was 7.96 folds higher than the plasma one and the plasma level of MDA was higher by 1.05 folds than the seminal one. No difference between patient and control plasma NGAL level was found. We noticed a strong correlation between plasma ORAC decreasing and MDA generation in semen (r=-0.753, p=0.000). Consequently, we have determined a cut-off of 1.035 m mol eq AA/l for the antioxidant defense level that predict semen MDA generation (Se=100%, Sp=94.4%; AUC=0.765, p=0.000). Data of the present study suggest that the plasmatic compensatory antioxidant enzyme NGAL is not associated with OS related infertility while the plasma ORAC may predict a high amount of semen toxic byproduct MDA. Furthermore, our data show no significant relathionship between semen parameters and the OS damage unless this latest may identify a part of the idiopathic infertility and may be included in routine chek-up.
