Clara naphthalene

Fanucchi MV, Buckpitt AR, Murphy ME, Plopper CG (1997) Naphthalene cytotoxicity of differentiating Clara cells in neonatal mice. Toxicol Appl Pharmacol, 144 96-110. 

Selective lung damage and necrosis occurred in Clara cells of mice that were administered naphthalene. It produced selective depression of pulmonary monooxygenase activities without accompanying changes in hepatic monooxygenease. A dose-dependent alteration of Clara cells (bronchiolar epithelial cells) was noted. 

The GSH content of freshly isolated rabbit Clara cells was 2.0310.59 nmol/10 cells it was depleted to 0.7510.06 nmol/10 cells by incubating with 200 (JiM diethyl maleate for 20 min (Horton et al. 1987). Cysteine was best able to support resynthesis of GSH. There was no evidence for participation of a cystathionine pathway for glutathione synthesis. In steady-state conditions, the GSH measured in isolated mouse Clara cells was in the femtomole range, but varied 4-fold between individual cells (West et al. 2000). Clara cells analysed in situ and in vitro confirmed this heterogeneity. The response of these cells to compounds that modulate GSH was also variable. Dimethyhnaleate depleted GSH, whereas GSH monoethylester augmented it. However, both acted nonuniformly in isolated Clara cells. The depletion of intracellular GSH caused a striking decrease in cell viability upon incubation with naphthalene. 

Naphthalene dissolved in corn oil and administered intraperitoneally to young C57BL/6J mice selectively damaged Clara cells (Mahvi et al. 1977). At 2 and 3 h after treatment of male, viral antibody-free Swiss Webster mice with 200 mg naphthalene/ kg, when most Clara cells had early signs of injury, few ethidium homodimer-1 permeable cells were... 

While bronchiolar epithelium in normal C57BL/ 6 mice contains cells that express high levels Clara cell 10 kDa secretory protein and CYP2F, and exhibit the characteristic pattern of naphthalene injury and repair, Clara cell 10 kDa secretory protein and CYP2F expression was less abundant in transgenic C57BL/g yS T cell knock-out mice (Van Winkle et al. 1997). In knock-out mice 1 to 2 days post injury, injury was not uniform within the terminal bronchiole. Distal ends of the bronchiole contained Clara cell 10 kDa secretory protein positive epithehal cells and were not injured. 

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