A Correlated Thin Section and Freeze-Fracture Study of <i>o</i>-Phenylphenol-Induced Alterations in the Rat Liver

Abstract

The ultrastructural changes in the liver cells of male Wistar rats induced by oral and subcutaneous application of o-phenylphenol were studied electron microscopically using the thin section and freeze-fracture technique. The rats were given the o-phenylphenol once at a dose of 2,500 mg/kg b.w. and were sacrificed 60 h after treatment. In the orally treated animals, alterations in the nuclei and nucleoli of the hepatocytes were the most prominent alterations. Furthermore, an increase in smooth endoplasmic reticulum, lysosomes and microbodies were found. After the subcutaneous injection of o-phenylphenol enlargements of the bile canaliculi, intercellular space and pathological alterations in the mitochondria were seen. A proliferation of the smooth endoplasmic reticulum, an increase of microbodies and a decrease in the rough endoplasmic reticulum could be found. Both groups showed an increase in small intracellular fat droplets in the hepatocytes. In general, the effects of the subcutaneous application on the liver were more pronounced than the effects of the oral application. Freeze-fracture replicas exhibited a disorganization of the zonulae occludentes and an apparent increase in the number and size of gap junctions. These alterations were interpreted as an attempt of the liver cells to counteract the intracanalicular pressure and to increase the mechanical stability of the liver tissue.

Effect of Silybin on hepatic cell membranes after damage by polycyclic aromatic hydrocarbons (PAH)

“…These alterations, which are not typical for PAHs, are induced by a variety of substances toxic to the liver [13][14][15][16][17]. The authors have determined that increased blood flow to the liver combined with the effects of the toxic substance causes cellular contacts to loosen in defined areas.…”

Seipin regulates ER–lipid droplet contacts and cargo delivery

“…After initial formation, LDs retain a functional connectivity with the ER, as manifested by their dynamic cargo exchange (Jacquier et al, 2011). Furthermore, live cell imaging demonstrated that LDs move in concert with the ER (Targett-Adams et al, 2003;Guimaraes et al, 2015), and electron microscopy (EM) revealed an intimate morphological relationship between the ER and LDs (Robenek et al, 2006;Ohsaki et al, 2008;Wolinski et al, 2011). However, proteins responsible for the maintenance of ER-LD contacts are so far unknown.…”