Ultrastructural changes induced by formaldehyde inhalation during pregnancy on liver of neonate rats

ABSTRACT

Occupational exposure to formaldehyde inhalation is seen commonly among anatomists. Most of the previous studies were devoted to study the effect of formaldehyde on upper respiratory tract. Little attention was paid to the effect of that chemical agent on the liver. Therefore, the aim. Of this work was to study the effects of formaldehyde inhalation during pregnancy on the ultrastructure of the liver of neonate rats. In the present study, a group of 30 healthy pregnant female rats and their offsprings were divided into 2 main groupsGroup [A] included the offspring of 10 pregnant rats [36 neonate rats] as control group. The mothers were kept in an ordinary room in a clean properly ventilated cages and were fed on a similar commercial laboratorydiet. Group [B] Consisted of the offspring of 20 pregnant rats [42 neonate rats]. The mothers of this group were kept in stainless steel cages in the dissection room. They were exposed to formaldehyde vapour in the usual concentration present in the dissection rooms for six hours I day five days/week during the whole pregnancy period [twenty one days]. Group[B] was again subdivided into 3 subgroups B1, B2 and B3 [each contained 14 neonate rats]. They were killed at the 1[st], 7[th] and 30[th] post-natal day respectively. During the period of study, all rats were observed daily for general conditions. The electron microscopic examination of the liver of subgroup Bi showed the following changes in hepatocytes regarding the nuclei, some of them showed destruction and irregularity of the nuclear membrane, others showed darkening of their nudeoplasm with increased peripheral condensation of chromatin. The mitochondrial changes were variable, some appeared dense pleomorphic and others appeared swollen with complete destruction of their cristae and membrane as well as loss of matrix leaving marked vacuoles of different sizes and shN?pes. There were proliferation of sER and dilatation of rER especially in the perinudlear area with mild increase in free ribosomes. Most of the cytoplasm showed apparent vesiculations and cavities of different sizes and multiple lipid droplets. The cellular cytoplasm showed electron dark particles and deposition of collagen fibrils. Infiltrating inflammatory cells were present within the portal tract. Glycogen granules were seen in the form of rosettes [cx granules] and single minute particles [beta granules]. Electron dark particles and fragmented microvilli were present in the dilated bile canaliculi. Lysosomal elements were also observed. Regarding subgroupB2, nucleoplasm showed mild darkening and aggregating masses of chromatin at nuclear periphary and its center. The cytoplasm showed variation in its density where most of the cell space had dark cytoplasm with dark mitochondria while theJemaining parts of cell space appeared of light density. Mitochondria showed swelling, partial destructed cristae and loss of matrix. Partial improvement on rough endoplasmic reticulum [rER] was noted. Glycogen rosettes were also seen in the cytoplasm. The subgroup 83 showed the smooth rounded nuclear contour with evident nucleolus and nearly normal dispersed nuclear chromatin was observed The nucleoplasm appeared of moderate electron denisty. Partial return of mitochondrial cristae was noted and their membrane was also more distinict than control group. Rough endoplasmic reticulum appeared nearly normal. Bile canaliculi still showed dilatation and fragmented microvilli