MSG treatment hindered the development of the testes. A and B are representative of the morphology of the seminiferous tubules (ST) of testes with IHC staining. Scale bar, 50 μm (A) and 3β-HSD positive Leydig cells with immunohistochemical staining. Scale bar, 20 μm (B). The positive cells were stained brown. The positive cells were cytoplasmic positive and membranous positive. In the middle and bottom panels are shown the average number of ST (C), the average diameter of ST (D) and the average number of 3β-HSD-positive Leydig cells per visual field (H). The numbers of spermatogonia (SG), spermatocytes (SC), and sperm per seminiferous tubule were counted separately (E, F, G). Star, seminiferous tubule; Arrow, 3β-HSD positive of Leydig cells; The means were compared using Student’s t-test. NSD, non-significant difference.