possible correlation between the testicular structure and short photoperiod exposure in young albino rats: light and electron microscopic study

ABSTRACT

Light is considered as the first ecological factor affecting primary productivity. Several studies have attempted to relate between seasonal changed environmental light factors and the reproductive system. The influence of environmental light on the anatomy and physiology of different organs has been investigated intensely in a different species. Therefore, this research was designed to examine the effects of a short duration of light exposure on the histological structures of rat testes. Eighteen young male albino rats were divided into control [I] and experimental [II] groups. They were kept for 8 weeks in separate cages. The rats in group I were exposed daily to a normal lighting cycle of 12 h light and 12 h darkness. Light was provided by a 20-W 4-ft fluorescent lamp. Group II was exposed daily to 4 h of light and 20 h of darkness. They were housed in a small room. Its windows were covered with a black cotton material. At the end of the experiment, all rats were anaesthetized with ether, and their testes were dissected out and processed for light and electron microscopic examination. In group II, spermatogenic cells of some seminiferous tubules appeared separated and exfoliated. The other tubules were destroyed, with acidophilic hyaline material. Loss of germ cells was confirmed by a significantly low sperm count. Some germ cells showed a vacuolated cytoplasm and disrupted intercellular bridges with the formation of giant cells. Sertoli cells showed active phagocytic capacity with the appearance of multivesicular bodies. Hormonal assay showed a low significant testosterone level; this was supported by the presence of inactive spindle-shaped Leydig cells. The present study confirmed that rats were structurally and functionally photosensitive. Therefore, the changes in the normal photoperiod could influence their reproductive functions