Spearman’s correlation coefficients for 97 semen samples.

<p>Bolded correlations are significant at p < 0.05. Correlations of interest for this study are framed.</p

Descriptive statistics for 97 semen samples.

<p>Descriptive statistics for 97 semen samples.</p

Scatter-plot and results of statistically significant linear correlation between KxZn/CaxCu ratio and parameter of spermatozoa hyperactivated motility (STR %) for samples taken from the group of men with normal spermiogram, although with expressed spontaneous spermatozoa hyperactivation.

<p>Increased concentrations of K and Zn with respect to Ca and Cu are related to low STR values revealing synergistic effects of these elements in relation to presence of spontaneous hyperactivation of spermatozoa.</p

Graphical display of variables contributing to principal component 1 (PC1) and principal component 2 (PC2) and amount of total variance explained per each PC showing strong association of sperm quality parameters including sperm concentration around PC1 and concentration of elements around PC2.

<p>The variables concentrated around graphical centre do not contribute significantly to these two PCs, although they could be interpreted by subsequent PCs describing remaining data variance. The projection of K, Ca, Cu, Zn and Y variables on PC1 describing 31% of total variance shows weaker negative correlation to motility parameters and sperm concentration. Higher concentrations of these elements negatively impact forward progression parameters and sperm concentration, but contribute to hyperactivation motility expressed as low STR and LIN, accompanied with low “elongation” (a morphological parameter). This also implies that hyperactivation activates on expense of forward progression. PC2 describing 21% of remaining variance shows that all elements are correlated between themselves although Br and Sr express lower contribution. Their higher concentrations are associated to greater forward progression and sperm concentration. These results imply that, although of secondary importance, the higher baseline status of elements improves forward progression and sperm concentration.</p

Synergetic Effects of K, Ca, Cu and Zn in Human Semen in Relation to Parameters Indicative of Spontaneous Hyperactivation of Spermatozoa - Fig 2

<p><b>A</b>. Scatter-plot and results of statistically significant linear correlation between K/Ca and Cu/Zn ratios for 97 patients recruited for this study. Samples taken from men diagnosed with normozoospermia, asthenozoospermia and oligoasthenozoospermia are distinguished by different symbols. <b>B</b>. Scatter-plot and results of statistically significant linear correlation between K/Ca and Cu/Zn ratios were checked for greater number of human semen samples. Samples taken from men diagnosed with normozoospermia (n = 30), asthenozoospermia (n = 98) and oligoasthenozoospermia (n = 47) are distinguished by different symbols. The negative correlation was confirmed to be valid for 175 semen samples at statistical significance of p = 0.00002.</p

The absolute contributions of variables to selected PC axes; (marked loadings ≥ 0.35).

<p>The absolute contributions of variables to selected PC axes; (marked loadings ≥ 0.35).</p

Box-plots of trace-element concentrations, patient ages, days of abstinence and sperm-quality parameters.

<p>Groups of men diagnosed with normozoospermia (N), asthenozoospermia (A) and oligoasthenozoospermia (OA) were statistically different with respect to all sperm quality parameters and sperm concentration. No significant difference was found in concentrations of chemical elements among these three groups of patients. Results of Mann-Whitney U test and Tukey HSD showed that A and N groups were statistically significantly different with respect to STR, LIN, “elongation”, VCL and ALH indicating increased expression of spontaneous spermatozoa hyperactivation among patients with normal spermiogram according to WHO criteria. The distribution of sperm quality parameters for OA group of patients was not compared to other two groups as being heavily influenced by “0” values.</p