ABSTRACT
Volatile substance abuse in general, and toluene inhalation in particular, for their neuropsychological effects, represents a significant problem in many developed and developing countries. The present work was designed to investigate the histopathological changes in the testis of adult male albino rats, induced by toluene vapour inhalation over different periods. The present study was carried out on forty adult male albino rats with body weights ranging from 60-100g. The animals were categorized into two groups: Group I: [Control Group] included ten rats received no treatment, Group II: [Toluene inhalants] included thirty adult rats exposed to toluene vapour inhalation. A clean dry piece of cotton was soaked with toluene liquid and placed in the covered cages three times daily, each for about thirty minutes for six days per week. These animals were subdivided into three equal subgroups according to the exposure period; Subgroup [A]: ten rats exposed to toluene vapour for two weeks, Subgroup [B]: ten rats exposed to toluene vapour for eight weeks, Subgroup [C]: ten rats exposed to toluene vapour for twelve weeks. At the end of each duration of the experiment, animals were scarificed by decapitation using light ether anesthesia after taking blood samples. I- Histological examination: Specimens were taken from the testis of all rats and processed for examination by light microscope using haematoxylin and eosin stain and ultrastructural study using the transmission electron microscope. II. Hormonal assay: The concentration of testosterone level, luteinizing hormone [LH] and follicle - stimulating hormone [FSH] were estimated by radio immunoassay. III. GAS chromatography: Concentration of toluene vapour in the blood was measured by High performance liquid chromatography. IV. Statistical analysis: The one way ANOVA test was applied to estimate the significant values of the hormonal assay for serum testosterone, LH and FSH and the 5% level of significance was chosen. The histopathological changes observed in the testis of rats exposed to toluene inhalation demonstrated its potentials to induce cytotoxic effects on the spermatogenic cells, Sertoli cells and the interstitial cells of Leydig. The severity of the toluene damaging potentials appeared to be dependent on and directly proportionate to the duration of toluene inhalation. So, the histological changes were mild and scattered in the testis specimens of group A [2 weeks inhalation] and was more severe in both eight and twelve weeks groups. The correlation between high performance liquid chromatography for toluene gas in blood, the biochemical gonadal and gonadotrophin hormonal assay and the histological assessment, explored the various mechanisms that were incorporated in the establishment of the toluene induced testicular injury. The present study proved the undoubting evidences for the damage potentials of toluene on the testis as the major reproductive organ in the male. Furthermore, the study showed the direct proportionality between the toxic effects of toluene vapor and the length of the exposure duration. Yet, the observed histological alterations were highly suggestive for a probable impaired reproduction in experimental animals which needs further study