Ali Louei Monfared

Formaldehyde (FA) is widely used in industrial and medical settings. It has long been suspected of causing adverse reproductive and developmental effects. However, the effects of exposure to FA on the reproduction are still a matter of scientific controversy. In this study, we evaluate the hypothesis that adverse developmental outcomes of the exposure to FA might be due to its effects on the placental structure. So, histological changes of the placenta in the mice exposed to FA gas were assessed at light and electron microscopy levels. A total of 40 pregnant Balb/C mice were randomly allotted to four groups in which the animals were exposed to FA at the doses of 0 (control), 7, 14 and 28 ppm, respectively, by inhalation, consecutively, for 8 h/d during the organogenesis period. On day 17 of gestation, the animals were killed and the histological specimens of the placentas were taken for light and electron microscopy studies. Also, morphological parameters of the placentas were measured manually. The results showed that the effects of FA on the placenta are not dose dependent. In the FA-exposed mice, an increase in the number and size of trophoblastic giant cells and an enlargement of spongiotrophoblastic cells in the basal zone of placenta were seen. Also, a significant increase in placental weight as well as the ratio of placental to fetal weight but a decrease in the fetal weight were found in the treated groups when compared with those in the control mice ( p < 0.05). Moreover, ultrastructural results demonstrated that the diameter of labyrinth interhemal membrane as well as the thickness of trophoblastic basement membranes were significantly increased in the FA-exposed mice. In addition, in the FA-treated animals, a severe accumulation of cytoplasmic droplets in the II and III trophoblastic layers of the placenta were seen. In conclusion, this study may suggest that the exposure to FA during the organogenesis period at doses of 7–28 ppm induces toxic changes in the placental structure. These changes disrupt placental functions and leads to a decrease in the fetal weight.

Phenolic compounds are common water pollutants and include a wide variety of organic chemicals. The effects of three sublethal concentrations of phenol on liver histology and some biochemical parameters of Oncorhynchus mykiss after 8 weeks exposure were investigated in this study. A total of 80 rainbow trout (O. mykiss) were randomly divided into four groups (n = 20). Control group was kept in water without any add-on material, while experimental groups were exposed to the concentration of 0.6, 1.2 and 2.4 mg/L of phenol solution. At the end of the study period, the weight of liver, condition factor (CF) and hepatosomatic index (HSI) were measured. Tissue and blood samples were taken separately for histologic evaluation and serum biochemical parameters assay, respectively. In fish treated with phenol, significant reduction in liver weight, CF, HSI ratio, diameter of hepatocytes and hepatocytes nuclear diameter (p < 0.05) was recorded. Total protein and albumin decreased significantly in treated fish in comparison with control (p < 0.05), but levels of cholesterol, glucose, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase in fish exposed to different concentrations of phenol showed a significant increase (p < 0.05). These findings showed that phenol could cause its harmful impacts even in very low concentrations.