RESUMO
Background: vitamin D has multifaceted function in human reproductive physiology. It has been revealed that vitamin D is involved in spermatogenesis, and semen quality can be linked to vitamin D status in men
Objective: evaluating the correlation of 25-hydroxy vitamin D [25-OHD] levels in serum with basic and advanced semen parameters and essential determinants of spermatozoa function
Materials and Methods: participants were categorized, based on semen parameters, into normozoospermic [NS] and oligoasthenoteratozoospermic [OAT] men. Serum level of 25-OHD was measured. Apoptotic status of spermatozoa, mitochondrial membrane potential and reactive oxygen species content of semen were assessed
Results: difference of 25-OHD concentration in serum of NS men versus OAT ones did not meet significance threshold. DNA fragmentation, reactive oxygen species content of semen and mitochondrial membrane potential state revealed significant difference between NS and OAT subjects. There were no significant differences in basic and functional semen parameters when men were stratified based on serum 25-OHD level. Taking both 25-OHD and semen categories [NS and OAT] into consideration did not indicate any significant difference in studied parameters. Total motility of spermatozoa was positively correlated with serum concentration of 25-OHD in all studied subjects. In addition, normal morphology of spermatozoa in NS men revealed a positive and significant correlation with levels of 25-OHD in serum
Conclusion: vitamin D may affect motility and morphology of spermatozoa. Lower content of serum vitamin D may affect fertility of men and should be considered in examination of men with abnormal spermogram
RESUMO
Myeloperoxidase [MPO], which is abundantly expressed in neutrophils, catalyzes the formation of a number of reactive oxidant species. However, evidence has emerged that MPO-derived oxidants contribute to tissue damage and initiation and propagation of inflammatory diseases, particularly, cardiovascular diseases. Therefore, studying the regulatory mechanisms of the enzyme activity is of great importance. For clarifying some possible mechanism of the enzyme activity, kinetic investigations of MPO in the presence of Copper [Cu], Cadmium [Cd], and Lead [Pb] ions were carried out in vitro. MPO was partially purified from human white blood cells using ion-exchange and gel-filtration chromatography techniques. Its activity was measured spectrophotometrically by using tetramethyl benzidine [TMB] as substrate. Purified enzyme had a specific activity of 21.7 U/mg protein with a purity index of about 0.71. Cu inhibited MPO activity progressively up to a concentration of 60 mM at which about 80% of inhibition achieved. The inhibition was non-competitive with respect to TMB. An inhibitory constant [Ki] of about 19 mM was calculated from the slope of repot. Cd and Pb did not show any significant inhibitory effect on the enzyme activity. The results of the present study may indicate that there are some places on the enzyme and enzyme-substrate complex for Cu ions. Binding of Cu ions to these places result in conformational changes of the enzyme and thus, enzyme inhibition. This inhibitory effect of Cu on the enzyme activity might be considered as a regulatory mechanism on MPO activity