POLYCHLORINATED BIPHENYL CONGENER 153-INDUCED ULTRASTRUCTURAL ALTERATIONS IN RAT-LIVER - A QUANTITATIVE STUDY

Alterations in the liver of male and female Sprague-Dawley rats fed PC B congener 153 (2,2',4,4',5,5'-hexachlorobiphenyl) at 0.5, 5, or 50 pp m concentrations in diets for 13 weeks were determined morphometricall y. A dose-dependent increase in hepatocyte volume was detected; the cy toplasmic compartment contributed to the increase in cell volume in an overwhelming fashion. Eighty percent and 250% increase in smooth endo plasmic reticulum volume and its surface area in hepatocytes were esti mated in animals of both genders from 5- and 50-ppm groups: respective ly; the organelle played the largest part in the increase in cytoplasm ic volume. Rough endoplasmic reticulum alteration was shown to depend on gender, where the volume per hepatocyte was augmented by 40% and 45 % in females of 5- and 50-ppm groups, respectively, however, 30% and 2 0% decreases in volume of this organelle were noted in males at those congener concentrations. A decrease of 13% in normal mitochondria volu me at 50 ppm concentration was observed, which may have been a consequ ence of a transformation of these mitochondria to abnormal types. Two types of abnormal mitochondria, named Type I and Type II, were defined : the former comprised mitochondria that had cristae which laying para llel to the long axis of the organelle and the latter showed C- or rin g-shaped profiles. Data analysis revealed a trend toward an increase i n abnormal mitochondria volume in the cells as the congener concentrat ion elevated. In addition, a threefold increase in the volume of lysos omal elements per hepatocyte was noted in 50 ppm PCB-fed rats of both genders. Also, a significant increase in peroxisome volume per cell in female rats was detected at a lower concentration than it was in the male. This study, which is a first ultrastructural quantitative invest igation on the effects of a PCB that included many parameters. The met hodology, and the data may prove useful to provide better understandin g of pathology in the evaluation and regulation of toxic chemicals. (C ) 1997 Elsevier Science Ireland Ltd.