Figure 5. Histochemical analysis of testis of the young and aged mice. (A) In the control group, the basement membrane (BM) of seminiferous tubules, Sertoli cells and sperms (arrowheads) showed staining affinity to PAS. (B) In the young mutant mice, the basement membrane (BM) appeared thick and PAS-positive and the interstitium is PAS-positive (arrowhead). (C) In aged mice, Leydig cells (IC) and giant cells (arrowheads) in the seminiferous tubules showed strong PAS-positive reactions. (D) In melatonin group, Sertoli cells and their associated spermatids (arrowheads) showed PAS-positive reaction. (E) In the control group, the Leydig cells (arrowhead) showed affinity to bromophenol blue (BB). (F) In young mutant mice, some giant cells (arrowhead) reacted positively to BB. (G) In aged mice, the degenerated seminiferous tubules (S) showed no or weak affinity to BB, while Leydig cells (arrowhead) showed strong BB- positive reactions. (H) In the melatonin group, the reaction was concentrated in Leydig cells (arrowheads). (I) Sudan black B stain showed a weak reaction in Leydig cells (arrowhead) of the control group. (J) A moderate reaction in Leydig cells (arrowhead) of young mice. (K) An evident increase in the number of positive- lipid droplets in interstitial cells (arrowhead) was observed in aged mice. (L) The reaction (arrowhead) was moderate in the melatonin group.