Reproductive toxic effects in the testes of BALB/c mice exposed to total diesel exhaust

This study used 50 male BALB/c mice divided into three groups [20 in each of test groups A and B and 10 in the control group C]. Group A and group B were exposed to total diesel exhaust [TDE]. The TDE exposures were performed in a cubic wooden box chamber [side length 50 cm] filled with TDE from a diesel fueled car. Group A was moved to the diesel filled chamber and exposed once a day for 30 minutes and group B was moved to the filled chamber and exposed once a day for 60 minutes. The control group was similarly manipulated for 60 minutes without filling the chamber with TDE. The experiment was carried out six days a week for 120 days. Four animals from group A and six animals from group B did not survive to the end of the experiment while the control animals did not have mortalities. Five of the remaining mice from each test group and 2 controls were sacrificed on the 40th day and on the 80th day. Remaining six mice in group A and four mice in group B and six mice from group C were sacrificed at the end of the experiment [120th day]. Testes and vasa efferentia were removed, testes were prepared into sections for histological, immunohistochemical staining and testicular biopsies [5 mg each] were used for Western blotting experiments to detect acrosomal proteins. Vas spermatozoa were prepared as smears for immuno-histochemical study. Down regulation of spermatogenesis reflecting structural damage of the seminiferous tubules was observed in animals sacrificed on the 40th day, this was progressive with time of exposure as seen in samples obtained on the 80th and 120th days The dependence on exposure time was also clear from comparison of sections from groups A and B, Severe oligozoospermia was detected in group A by the end of 80th days and in group B by the end of the 40th day. By the end of the experiment [120 days], the seminiferous tubules from the testes of the two test groups A and B were containing Sertoli cells only. Immunohistochemical staining of testicular sections and vas sperm suspensions using monoclonal antibodies for internal acrosomal proteins revealed a concomitant ultrastructural damage of spermatozoa in the form of defective or absent acrosome and increased proportion of abnormal sperm head morphology. The progressive decrease of sperm and spermatid -specific proteins in testicular biopsies was observed in the immuno blots. It is concluded that exposure to diesel exhaust has a massive reproductive toxicity in male mice manifested by suppression of spermatogenesis and abnormal ultra structures of vas spermatozoa. Also, the reproductive toxic effect of diesel exhaust exposure is both dose [exposure time]-dependent and duration [repeated exposures]-dependent

Histological study on the toxic effect of 2-bromopropane on the seminiferous tubules of adult male albino rats

2-Bromopropane [2-BP] is a haloalkane used in industry as an alternative to ozone layer depleting solvents. It has recently been suspected to be a causative agent for some reproductive dysfunctions in both male and female workers exposed to it in electronic factories. The study was carried out to evaluate the possible toxic effects of 2-BP administration on the seminiferous tubules [S. Ts] of rat testis, and its potential reversibility after 2-BP withdrawal. The study was conducted on 30 adult male albino rats weighing from 100-150g each. They were categorized into 3 equal groups. Group I: served as a control group. Group II: rats received daily subcutaneous injection of 2-BP [400 mg/kg b.w.] for 28 days. Group III: rats received 2-BP in the same dose and for the same duration as group II followed by a further 28-day recovery period. At the end of experiment, blood samples were collected to detect testosterone levels, and the rat testes were weighed and examined for the daily sperm production. Specimens were taken from the testes of all animals and subjected to both light and electron microscopic examinations. 2-BP administration [in group II] significantly decreased absolute testicular weight and daily sperm production as well as serum testosterone levels. Histologically, atrophy of the S.Ts accompanied by interstitial oedema was evident. Moderate to severe degenerative changes involving all types of spermatogenic cells, including spermatogonia, were also demonstrated. Furthermore, Leydig cells depicted ultrastructural evidence of decreased activity. After a 4-week recovery period [group III], mild increase in serum testosterone levels as well as other laboratory parameters were noticed. However, they were still much less as compared to the control. Histologically, only limited amelioration of the testicular lesions in the germinal epithelium as well as Leydig cells was revealed. Such persistent lesions were attributed to the damaging effect of 2-BP on testicular stem cells; spermatogonia. The study demonstrates vulnerability of the testicular tissue to 2-BP intoxication. Therefore, careful consumption of 2-BP containing solvents and pharmaceuticals is necessary