OBJECTIVETo analyze the level of the oxytocin (OT) and the expression of oxytocin receptor (OTR) in males with idiopathic infertility.

METHODSSixty-five infertile males aged 20 -45 years were divided according to their semen parameters into an idiopathic oligozoospermia group (OG, n = 20), an idiopathic asthenozoospermia group (AG, n = 25), and an idiopathic oligoasthenozoospermia group (OAG, n = 20). Another twenty 20-45 years old healthy male volunteers with a natural childbearing history were included in the control group (CG). All the subjects were detected for the contents of luteinizing hormone (LH), follicle stimulating hormone (FSH) , testosterone (T) and OT, and analyzed for the expression of OTR by sequencing the functional region of the OTR promoter (OTRP), OTR-mRNA, and OTR-COOH terminus. The gene sequences were compared using DNASTAR-MegAlign, Western blot values changed into enumeration data, and all the data analyzed by one-way ANOVA and Dunnette's multiple range t-test.

RESULTSA significantly lower content of OT was observed in CG ( [79.30 +/- 3.83] pg/ml) than in OG ([118.53 +/- 7.69] pg/ml, AG ([108.81 +/- 5.66] pg/ml) and OAG ([103.71 +/- 4.54] pg/ml) (F(0.05/2[2,82]) = 8.29, P < 0.01). The content of LH was significantly lower in AG ([4.26 +/- 0.31] IU/L) and OAG ([4.55 +/- 0.40] IU/L) than in OG ([6.77 +/- 0.57] IU/L) and CG ([7.19 +/- 0.50] IU/L) (F(0.05/2 [2,82]) = 11.64, P < 0.01), and so was the content of FSH in AG ( [5.02 + 0.39] IU/L) than in CG ([8.91 +/- 0.91] IU/L), OG ([11.86 +/- 1.76] IU/L) and OAG ([8.82 +/- 1.03] IU/L) (F(0.05/[2,82]) = 7.22, P < 0.01). There were no significant differences in the T content among the four groups (F(0.05/2[2,82] = 0.42, P = 0.739). No evident gene mutation was found in OTRP and OTR-mRNA gene sequencing. Human OTRs in the lymphocytes were monomers and oligomers, mostly tetramers and hexamers. There were obviously more monomers in AG (0.41 +/- 0.03) and OAG (0.13 +/- 0.01) than in OG (0.05 +/- 0.004) and CG (0.05 +/- 0.003) (F(0.05/2[2,82]) = 115.50, P < 0.01), while the number of oligomers was markedly decreased in 20% of the cases in AG.

CONCLUSIONSignificant differences in the content of OT and expression of OTR between fertile and infertile men suggested an association of OT with male infertility. The decreased expression of OTR oligomers and increased expression of monomers may be related to idiopathic asthenozoospermia, which has provided a new insight into the pathogenesis and treatment of male infertility.