Phenotype Image Detail

Image

Caption

Comparison of histological sections through the testes (A-F) of epididymal ducts (G-H) of wild type (A, D, & G) and Rara^tm1Ipc/Rara^tm1Ipc (B, C, E, F & H) mice. A: Parenchyma of wild type testis is composed of seminiferous tubules (T) with active spermatogenesis and intertubular spaces containing capillaries (CP) and Leydig cells (L). The aspect of the seminiferous epithelium (or germline epithelium) varies between tubules at different stages of the spermatogenic cycle; however, all tubules contain primary spermatocytes (C), each of which will eventually yield four spermatozoids. B, basement membrane. B & C: Parenchyma of testis of homozygous mutant mouse shows a patchy pattern of seminiferous tubule lesions. These cover a wide spectrum, ranging from rare tubules with complete spermatogenesis (e.g. T1) to tubules containing only Sertoli cells (e.g., T2) which may be enlarged, thus filling the tubules (e.g. T2 in C). A majority of tubules lack primary spermatocytes (C). In addition, the seminiferous epithelium shows numerous large, clear, rounded spaces (vacuole-like, V) and occasional clusters of degenerating spermatogenic cells (large arrow in C). In the intertubular spaces, focal hyperplasia of the Leydig cells (L) is observed between atrophic seminiferous tubules (C). This hyperplasia is likely to result from the decrease in tubular diameter (compare T3 in C with T in A). D-F: High magnification micrographs of the walls of seminiferous tubules. D: In wild type testis, the seminiferous epithelium consists of supporting cells, the Sertoli cells (S) and spermatogenic cells. The spermatogenic cells proliferate from stem spermatogonia (G), located in contact with the basement membrane (B), and differentiate from the periphery toward the lumen of the seminiferous tubules. This process yields different ontogenetically related cell types arranged in concentric layers-i.e. spermatogonia (G), primary spermatocytes (C), round spermatids (D), and maturing spermatozoids (Z). E & F: Two different aspects of the seminiferous epithelium in homozygous mice. Most frequently, the early stages of spermatogenic cell differentiation (e.g., spermatogonia and primary spermatocytes) are missing (E) (in such a degenerate epithelium, spermatogenesis no longer occurs). In rare cases, all stages of spermatogenic cell differentiation, including the round spermatids (D) and maturing spermatozoids (Z), are seen (F). G: Section, through the tail of a wild type epididymal duct; spermatozoids (Z) fill the lumen. H: Section through the tail of an epididymal duct of a homozygous mutant; the lumen of the duct contains acidophilic (blue) material which is also present within large vacuoles (V) in the epithelium lining the duct (E), possibly as a consequence of extensive cellular absorption; spermatozoids (Z) are occasionally identified in the lumen. Organs were immersed-fixed in Bouin's fluid. Paraffin sections (5um thick) were stained with Groat's hematoxylin and Mallory's trichrome. Magnifications: A-C, G & H: x217; D-F: x1085

Copyright

This image is from Lufkin T, Proc Natl Acad Sci U S A 1993 Aug 1;90(15):7225-9. Copyright 1993 National Academy of Sciences, U.S.A. J:13574

Associated Alleles

Symbol	Name
Rara^tm1Ipc	retinoic acid receptor, alpha; targeted mutation 1, Pierre Chambon

Associated Genotypes

Allelic Composition	Genetic Background
Rara^tm1Ipc/Rara^tm1Ipc	involves: 129S2/SvPas