Figure 3: Quantification of sperm head PLCζ fluorescence with relation to advancing age in sperm from (a) both strains of mice collectively, (b) B6 mice, and (c) CD1 mice. (d) Polynomial regression models indicating the dynamic relationship between PLCζ fluorescence and advancing male age in both B6 and CD1 strains of mice. r values placed adjacent to each model indicate the strength of the constructed models. Data are represented as mean ± s.e.m.*Statistically significant differences (P ≤ 0.05). Comparisons are made between groups overlapped by the upper line. a.u.: arbitrary units; B6: C57BL/6 inbred mouse strain; CD1: outbred mouse strain; s.e.m.: standard error of the mean; PLCζ: phospholipase C zeta.