Stereological analysis of hamster cheek pouch epithelium after one application of DMBA or turpentine.

Both cheek pouches of two groups of five male hamsters were treated with one application of either 50% turpentine in liquid paraffin (TLP50) or a 0.5% solution of dimethylbenz(alpha)anthracene in liquid paraffin (DMBA); animals were killed 48 h later. Five untreated animals served as controls. Mucosal specimens were removed from each pouch, fixed in normal-acetic-alcohol and processed for light microscopy. Sections were cut at 4 micrometer and stained with haematoxylin and eosin. A systematic random sampling method was used to obtain sections for sterological analysis. Grids for point and intersect counting were superimposed on the projection screen of an automatic sampling microscope. Results showed that the epithelial nuclear-cytoplasmic ratio, nuclear density, nuclear diameter and surface area interface ratios were similar for the experimental groups and, with the exception of the last parameter, differed significantly from controls. The volume proportion of TLP50-treated epithelium was significantly larger than that of DMBA-treated epithelium. Derived values for the average nuclear volume in both experimental groups were almost twice that of controls; the cytoplasmic volumes were more than doubled. At 48 h the epithelial response to a single application of TLP50 or DMBA was essentially similar except that TLP50 probably induced greater hyperplasia.