Mitochondrial volume densities in the smokeless tobacco-treated hamster cheek pouch epithelium

DepartmentofOralMedicineandDiagnosticScience,CollegeofDentistry,UniversityofIllinoisatChicago,Chicago,IL,USAOBJECTIVES: To compare the morphological changesand quantitative distribution of mitochondria in thehamster cheek pouch (HCP) epithelium treated withsmokeless tobacco (ST).MATERIALS AND METHODS: Archives of experimentalmaterial from previously published studies (Ashrafi et al.,1992) were utilized. Animals in experimental groupreceived moist ST (snuff) in their right pouch, 5 daysweekly for 24 months, while no snuff was given to controlgroup. After 24 months, the epithelial tissues wereprocessed for electron microscopy study. Volume densi-ties of mitochondria were assessed by morphometry.MAIN OUTCOME MEASURES: Mitochondrial volumedensities in the two groups, experimental vs control.RESULTS: In both control and experimental groupsmitochondria were concentrated between the nucleusand basal cell plasma membrane. A decrease in the meanmitochondrial volume density (Vvmit) was observedfrom the basal layer to the more superficial layers in bothgroups. The experimental HCP displayed more mito-chondria than control, and the granular epithelial celllayer in experimental group showed significantly a highermean Vvmit than the control group (P ¼ 0.03). It wasconcluded that greater numbers of mitochondria wereretained in ST-treated granular cells of the hyperplasticepithelia than in the normal epithelium.Oral Diseases (2003) 9, 138–143Keywords: hamster cheek pouch epithelium; smokeless tobacco;mitochondria; mitochondrial volume density; granular cells