Evaluation of the toxic effect of polycyclic aromatic hydrocarbons on semen of infertile workers in diesel and engine workshops: a prospective controlled study

ABSTRACT

The purpose of this study is to prove the toxic effect of exposure to polycyclic aromatic hydrocarbons [PAHs] on semen of infertile workers in diesel and petrol engine repair workshops. Urine and semen samples from 20 male workers exposed to hydrocarbons in diesel and petrol engines repair workshops for at least 2 years were collected. Urinary excretion of urinary 1-hydroxyrene [1-OHP], the most reliable indicator for PAHs exposure, was measured. Semen analysis and annexin -V bioassay were performed for all workers [during exposure and one year after precaution against exposure] and non-exposures [control] to document the toxic effect of PAHs exposure. PAHs exposed males showed six fold increase in 1-OHP excretions as compared to the control group. While semen volume is the same in both groups, there was significant increase in the percentage of non-aggregated sperms between the exposed and the control groups [45 +/- 26.17 and 11 +/- 7, respectively]. There was significant decrease in sperm count [Million / ml] in the exposed than the control group [44.4 +/- 37.79 and 110 +/- 55, respectively]. Asthenozospermia was found either alone or in combination with other abnormalities in 55% of the ejaculates from exposed workers, whereas, it was found alone in only 15% of the control group. Normal forms of the sperms and semen's viscosity were found significantly lower in the exposed group as compared to control group. The mean value of apoptotic sperm cells that have positive annexin-V was 42.5 +/- 14.09, while; the control group has shown no apoptotic sperm cells. Moreover, necrotic sperm cells were significantly increased in semen of exposed workers when compared to semen of control group [5.5 +/- 3.8 and 1.1 +/- 0.05, respectively]. Workers who had longer duration of exposure to PAHs had higher levels of urinary 1-OHP, percentage of annexin-V cells, lower sperm counts, lower motility, increased percentage of aggregated sperms and decreased percentage of normal sperm [r 0.48, 0.45, -0.74, -0.79, 0.46, and 0.69, respectively]. On the other hand, after one year of precaution against exposure to PAHs all the above-mentioned parameters were spontaneously improved; level of urinary 1-OHP, ejaculate volume, nonspecific aggregate, sperm count, sperm motility, normal sperm form and sperm vitality [2.4 +/- 0.9, 3.5 +/- 1.6, 15 +/- 9.6, 56.5 +/- 30, 55 +/- 15, 60 +/- 25 and 70 +/- 23, respectively]. This study documented the deleterious toxic effect of PAHs on semen of exposed males in diesel and engine workshops that could be reversed by stoppage of exposures. However a study on a bigger number of patients is required to assess the exposure time to induce changes in semen parameters and the time needed for reversal of the toxic effect of the PAHs. Furthermore, longer follow up is recommended to evaluate the fertility of those workers