ABSTRACT
Methyl tertiary-butyl ether [MTBE] is used to reduce carbon monoxide and ozone in urban air and to boost fuel octane. There is a lack of knowledge in the literature about the histomorphometric changes of the testis following exposure to MTBE. Therefore, this experimental study was performed to determine the effect of oral exposure to MTBE on histologic and histomorphometric changes of testis in adult rat. A total of 25 adult male Sprague-Dawley rats were randomly divided into five equal experimental groups: control, almond oil and three treatment groups which received 400, 800 and 1600 mg/kg/day MTBE in almond oil by gavages for 30 consecutive days. Histomorphometric analysis showed no significant difference in absolute and relative testis weight, connective tissue thickness, germinal epithelium height, tunica albuginea thickness and Sertoli cell numbers between experimental groups [P>0.05]. However, trend analysis showed that the seminiferous tubule diameter increased and interstitial cell numbers as well as spermatocyte and spermatid cell numbers decreased significantly in MTBE treated groups [P<0.05]. It may be concluded that MTBE could exert adverse effects on spermatogenic cells in adult rat. Whether the observed changes in the present study are due to the direct effect of MTBE via passing blood-testis barrier or its indirect effect through another mechanism should be elucidated in future studies.
ABSTRACT
The aim of this investigation was to study macroscopic and microscopic structures of ovaries in Barbus grypus of Karoon river and their changes during annual maturation cycle. For this purpose, 120 adult B. grypus with a mean weight of 835.0 to 1012.0 g, were caught from Karoon river and transferred alive to the laboratory. After biometrical studies, the weights and morphological appearances of gonads were recorded. Then, tissue samples from the anterior, middle and posterior portions of the gonad were excised and fixed in Bouin's solution. For microscopical studies, 5 micro m paraffin sections were prepared and stained with haematoxylin and eosin and periodic acid Schiff [PAS]. Gonado-somatic indices, macroscopical and microscopical changes of ovaries were studied during different months of the year. The results showed that gonado-somatic index ranged from 0.35 +/- 0.080% in September to 2.25 +/- 0.321% in June, and the maximum values were seen in June. Cyclic changes of ovarian maturation were divided into seven stages histologically. Ovarian maturation cycle in B. grypus began in late summer. Spawning period of B. grypus continued approximately from late April to early August, which indicated that B. grypus has a prolonged spawning season. Ovarian type of B. grypus was group synchronous with a capacity for multiple ovulations within a reproductive season