Ali Louei Monfared, Sahar Hamoon Naward, Ali Mohammad Bahrami and Ehsan Hosseini
Formaldehyde (FA) as a major source of occupational pollutant is commonly used in the industrial and medical settings. It has been demonstrated that FA exposure in industry causes health impairment especially immune profile. Therefore, the aim of the present work was to characterize its potential immunotoxicity in mice. Forty male Balb/C mice were exposed to FA gas as levels of 0 (control), 7, 14 and 28 ppm, during 8 hours/day over a period of 30 consecutive days. In the end of experiments, all of mice were anesthetized; the blood samples were taken and total as well as differential leucocytes counting were carried out. In addition, tissue specimens were taken and histological alterations of the spleens, thymuses, adrenal glands and sub iliac lymph nodes were examined using optical microscope. The diameters of splenic as well as lymph nodes follicles were lower than the control, whereas the splenic megakaryocyte counts were found to be higher in the FA exposed animals. Also, thymus tissue in the experimental animals has been affected and its lymphoid cells population shows a significant decreasing. Moreover, histometric assessment revealed the diameters of tymic cortex and medulla was significantly lower than those of the controls. Finally, the total leucocytes count significantly declined in the FA exposed animals. Other examined immunological parameters as well as adrenal glands's structure was not different from those of the controls. Histological study, histometrical analysis and peripheral blood cells counting indicate that inhalation of FA gas has a harmful impact on the immunocompetent organs in the mice.
