MMP2, MMP9 and TIMP2 polymorphisms affect sperm parameters but not fertility in Polish males.

Proper function of the blood-testis barrier is pivotal to spermatogenesis. Synchronised action of matrix metalloproteinases (MMP) and their inhibitors (TIMP) is mandatory to maintain dynamic balance of the barrier. Therefore, the association of functional genetic variants of MMP-2, MMP-9 and TIMP-2 and male infertility was studied. A total of 416 infertile males and 421 healthy subjects were genotyped for 7 SNPs within MMP2, MMP9 and TIMP2 genes, along with the assessment of semen parameters (concentration, motility and morphology of spermatozoa). No association was observed between the studied genotypes and male infertility. However, higher sperm concentration was associated with TIMP2 rs8080623 C and rs2277698 T variants among infertile men, and with MMP9 rs17576 A minor allele in controls (p < .05). TIMP2 rs9900972 T and rs2277698 T allele were associated with higher percentage of morphologically normal spermatozoa among controls. MMP2 rs2285053 TT homozygous infertile patients presented higher percentage of spermatozoa displaying nonprogressive motility. Haplotype analysis revealed strong linkage disequilibrium between the studied loci (5 of 8 possible TIMP2 haplotypes, and 3 of 4 possible MMP2 and MMP9 were found). None of the haplotypes showed association with infertility. This study results suggest an association between MMP9 and TIMP2 SNPs with sperm parameters, but not infertility.

Membrane stability and mitochondrial activity of human-ejaculated spermatozoa during in vitro experimental infection with Escherichia coli, Staphylococcus haemolyticus and Bacteroides ureolyticus.

The aim of the study was to examine an in vitro effect of the three bacterial strains (Escherichia coli, Staphylococcus haemolyticus and Bacteroides ureolyticus) on ejaculated spermatozoa with reference to sperm membrane integrity and mitochondrial activity. The study was carried out on swim-up-separated spermatozoa from 12 normozoospermic volunteers. Sperm plasma membrane stability was evaluated by the LIVE/DEAD Sperm Viability Kit and by the merocyanine 540 test. Mitochondrial activity was evaluated using the JC-1 test as well as the NADH-dependent NBT assay. The percentage of dead cells was significantly higher in spermatozoa treated with B. ureolyticus as compared to that of control spermatozoa (P < 0.01). All the bacterial strains applied affected sperm plasma membrane architecture measured by M540 test (P < 0.01). Moreover, the presence of E. coli or B. ureolyticus was connected with significant decrease in both the number of cells with high mitochondrial transmembrane potential (ΔΨm) and the cells with normal oxidoreductive function of mitochondria (P < 0.05 as compared to untreated cells). To conclude, the contact of bacteria with ejaculated spermatozoa can be a reason for severe injury of sperm membrane stability and mitochondrial activity with potential consequences for male fertility.