Figure 7. Immunohistochemical expression of VEGF and c-kit in young and aged mice. (A, E) VEGF expression in spermatocytes and spermatids (arrowheads) in the control group. (B, F) The young mutant mice showed overexpression of VEGF (arrowheads). (C, G) In aged mice, the reaction was weak and only the spermatocytes were immunostained (arrowheads). (D, H) In melatonin group, the reaction was concentrated in spermatocytes and spermatids (arrowheads). (I) c-kit expression was immunolocalized in spermatogonia (arrowhead) and interstitial cells (arrow) in the control group. (J, K) In young and aged mutant mice, the reactions were intense at the spermatogonial level (arrowheads). (L) The reaction in melatonin group was observed in spermatogonia (arrowhead) and Leydig cells (arrow).