Figure 1.

Characterization of isolated Leydig stem cells from adult mouse testes. Spindle‐shaped Leydig stem cells can be maintained in culture as demonstrated with (A) high power photomicrograph. The isolated cells expressed platelet‐derived growth factor receptor alpha (PDGFRA) protein (green) indicative of Leydig stem cells, SOX9 indicative of Sertoli cell population, and alpha smooth muscle actin indicative of peritubular myoid cells. Rabbit IgG served as a negative control using 4′,6‐diamidino‐2‐phenylindole nuclear stain. Scale bar = 75 μm. (B): Figure shows that differentiation could be induced in the cultured cells. The presence of mature Leydig cells was confirmed with cells staining positive (Red) for 3BHSD. Scale bar = 75 μm. (C): Fluorescence‐activated cell sorting, showing population of PDGFRA‐, 3BHSD‐, and SOX9‐positive cells in the culture. Abbreviations: BHSD, beta hydroxysteroid dehydrogenase; DIM, differentiation inducing medium; PDGFRA, platelet‐derived growth factor receptor alpha; αSMA, alpha smooth muscle actin.