Effects of simultaneous formaldehyde vapor and noise exposure on sperm parameters and pituitary-gonadal axis in adult male mice

Some reports suggest the adverse effect of formaldehyde on testis tissue-testosterone and sperm parameters. The workers in most of the workplaces are simultaneously exposed to formaldehyde and acoustic noise. Since noise can reinforce the harmful effects of some chemical pollutants, this study investigates the simultaneous effects of formaldehyde and noise exposure on sexual hormones concentration, and on sperm count and mobility in adult male mice. In this experimental study, 48 adult male mice were randomly assigned to one control and three experimental groups. Experimental groups F, N and NF were exposed to formaldehyde vapor, noise (100 dB, 700-5700 Hz) and simultaneous formaldehyde and noise, respectively, for 10 days (8 hours a day). At the end of the exposure period, 24 hours later, half of the mice in each group were sacrificed after blood was taken from the heart. The other half were sacrificed 35 days after the end of exposure. Plasma concentrations of sexual hormones were measured by using the ELISA method. The epididymis was also surveyed for sperm analysis by the CASA system. The present study indicates that simultaneous exposure to formaldehyde and noise (at frequencies of 1-4 kHz) may lead to the reduction of serum testosterone and LH levels and also the reduction in the number of progressive motile sperms.