In seasonally breeding birds, an increase in testicular
recrudescence mainly involves gamete production, Sertoli cell development and
an increased number of Leydig cell production. After successful breeding, a
rapid postnuptial testicular regression occurs. An investigation was done to
elucidate seasonal histomorphological changes of Leydig cells in Japanese
Jungle crows (Corvus macrorhynchos).
Histologic data of Leydig cells regarding their locations in the interstitium,
appearance and disappearance of lipoidal materials in their cytoplasm, and
fibroblasts like precursor cells were studied. The photomicrographs were
processed with Adobe Photoshop CS5 for expected size and DPI and saved in JPG
format. Finally, the photomicrographs were numbered and placed in the
manuscript. In the non-breeding season, in the interstitium, clusters of Leydig
cells were found in abundant numbers. They looked foamy, white and easily
visible. Their nuclei were found small and are located eccentrically. During
recrudescence, the Leydig cell became less foamy and less white. In peak
breeding season, the Leydig cells showed bigger in size and the nuclei became
prominent. Cytoplasmic lipoidal material was lowest and cytoplasm was found
dense pink. At the end of the breeding period, a heavy accumulation of lipid
materials occurred in the Leydig cell. The clusters of Leydig cells were
visible and looked white and foamy again. During this transition,
disintegration of Leydig cells occurred after pycnotic nuclei of Leydig cells
were found. During involution, a new generation of fibroblast-like cells
appeared in the interstitium. Within the fibroblast-like cells, some of them
became lipoidal by accumulating lipid materials. Thus a new generation of
Leydig cells appeared in the interstitium. These lipoidal cells are thought to
be a new generation of Leydig cells for the next breeding season. This study
suggests that in seasonally breeding birds, new generation of Leydig cell is
derived from fibroblastlike cells of the interstitium. The study concluded that
the beginning of the regeneration phase marks the end of the secretory cycle of
the Leydig cells although their ultimate fate seems to be in doubt. During this
period a new generation of interstitial cells is derived from fibroblast-like
cells. Further studies are needed on how quantitative information on
histo-architectures of Leydig cells at the ultrastructural level correlates
with serum LH (luteinizing hormone) and testosterone levels during breeding and
nonbreeding season in wild birds.
Author
(s) Details
Muhammad
Nazrul Islam
Department of Animal Science, Faculty of Agriculture, Utsunomiya
University, 350 Minemachi, Utsunomiya, Tochigi 321-8505, Japan and Department
of Anatomy and Histology, Faculty of Veterinary and Animal Science, Sylhet
Agricultural University, Sylhet-3100, Bangladesh.
Masato
Aoyama
Department of Animal Science, Faculty of Agriculture, Utsunomiya
University, 350 Minemachi, Utsunomiya, Tochigi 321-8505, Japan.
Shoei
Sugita
Department of Animal Science, Faculty of Agriculture, Utsunomiya
University, 350 Minemachi, Utsunomiya, Tochigi 321-8505, Japan.
Please see the book here:- https://doi.org/10.9734/bpi/acmms/v4/2672
