Seasonal variation in the ultrastructure of the Sertoli cells in Egyptian Nubian (Zaraibi) goat bucks

This research was carried out on 10 Egyptian Nubian goat bucks, to study the effect of season on the ultrastructure of the Sertoli cells. At the end of each of the four seasons of the year, testicular biopsies were obtained surgically from the testes from three bucks for histological and cytological studies. In the basal portion of the Sertoli cell, the nucleus was located near the basement membrane and was irregular in outline. Intermediate filaments were observed around the nucleus. A multivesicular nuclear body, composed of numerous vesicles of different sizes and ribosome-like structures, were detected within the nucleus. The season of the year had an effect on the nucleus diameter and sectional area. The nucleus diameter was smallest during spring, while being greatest during autumn. The sectional area of the nucleus showed reduced values in spring than in the other seasons. The majority of cell organelles were situated in the basal portion of the cytoplasm. These organelles showed different phenomenon during the different seasons. The mitochondria showed a clear change in shape (ovoid or elongated), number and sectional area during the different seasons. The number of mitochondria per 100 m2 of cytoplasmic sectional area was maximal during summer, followed by autumn (94.3 and 92.8, respectively). The total mitochondrial sectional area during spring was 2.4 m2. This area increased in summer and autumn by 333 and 404%, respectively. A well-developed laminated smooth endoplasmic reticulum (sER) was frequently found in the cytoplasm of the Sertoli cells. Season of the year influenced the diameter of sER. In summer and autumn the sER was fully developed to occupy a large part of the cell, with a diameter of 0.049 and 0.033 m, respectively. This value was minimal during the spring and winter seasons. Lysosomes and large lipid droplets were also recognized. The Golgi complex appeared only in the supranuclear region. The apical head of the slightly elongated spermatids was occasionally surrounded by the laminated sER. It could be concluded that season of the year influences the activity of the Sertoli cells. The activity increases in summer and autumn and this is reflected on the ultrastructure, spermatogenesis and sexual activity of the Egyptian Nubian bucks. © 2007 Elsevier B.V. All rights reserved.