Figure 4. Semithin section of the interstitium in the young and aged mice. (A) In the control group, the interstitium contained Leydig cells (IC), myoid cells (asterisk), telocytes (arrowhead) and blood capillaries (BC). (B, C) The young mutant mice showed many lipid droplets in the Leydig cells (arrowhead), and normal myoid cells (asterisks). (D, E) Significant increase in the number of Leydig cells and their lipid droplets (arrowheads, IC) was detected in the aged mice. Note the presence of mast cells (boxed areas). (F) Dendritic reticular cells (arrowheads) were recorded around the blood capillaries (BC), among the affected interstitial cells (IC). (G–I) In melatonin group, the Leydig cells (IC) return to their normal number with widening in the lumen of blood capillaries (BC) and increase in the number of the telocytes (arrowheads).