"All rats that were found dead or were sacrificed in extremis before the end of the study were necropsied. Ten rats per gender per group were necropsied 12 months after study initiation and surviving rats were necropsied at 24 months. The lungs, brain, heart, liver, spleen, kidneys, ovaries, adrenal glands, and testes were weighed and organ weight/body weight and organ weight/brain weight ratios were calculated."

"The following tissues were collected from all rats (tissue integrity permitting): skin, bone marrow (sternum and femur), lymph nodes (mandibular and mesenteric), spleen, thymus, aorta, heart, trachea, lungs, nose, larynx, pharynx, salivary glands, esophagus, stomach, liver, pancreas, small intestine (duodenum, jejunum, and ileum), large intestine (cecum, colon, and rectum), tongue, kidneys, urinary bladder, pituitary gland, thyroid - parathyroids, adrenal glands, prostate, mammary glands, testes, ovaries, epididymides, uterus, seminal vesicles, vagina, brain (includes sections of medulldpons, cerebellar cortex, cerebral cortex), spinal cord (cervical, thoracic, lumbar), sciatic nerve, thigh muscle, sternum and femur, eyes, exorbital lacrimal glands, Harderian glands. Collected tissues were preserved in an appropriate fixative until processed. Tissues collected from rats in the 50,000 ppm and control groups and from all rats that were found dead (tissue integrity permitting), were sacrificed in extrernis, or were accidentally killed, were further processed to slides, stained with hematoxylin and eosin, and examined microscopically. Lungs, liver, kidneys, nose, possible target organs, and relevant gross lesions from rats in the 2000 and 10,000 ppm groups were also processed to slides and examined microscopically."

"Incidence of clinical observations was evaluated by the Cochran-Armitage test for trend. If the trend test was positive for the high and intermediate concentration groups (p < 0.05), the incidence observed in the lowest concentration group was compared to the control group by using Fisher’s exact test. Survival among groups was compared with the Cochran-Armitage test and the Fisher’s exact test. Bartlett’s test for homogeneity of variances was performed on the clinical laboratory data and organ weight parameters. If the results were significant (p < 0.005), nonparametric procedures (Kruskal-Wallis and Mann-Whitney U tests for clinical laboratory data and Dunn’s test for organ weight data) were used to compare means from the control group with each of the treatment groups. Increases in the incidences of all microscopic observations in tissues specified in the protocol were statistically evaluated. The Cochran-Armitage trend test was applied to all microscopic observations in those instances where all tissues (subject to availability) were evaluated in all groups. If the trend test was positive for all 50,000 and 10,000 ppm groups (p < 0.05), the incidences observed in the lowest concentration group were compared to the respective control group lesion incidence by using the Fisher’s exact test."

"For those tissues not examined microscopically in all groups, the Fisher’s exact test was used to compare the control and 50,000 ppm group lesion incidences. If the Fisher’s exact test resulted in p < 0.05 for a lesion in a given tissue, then this tissue was microscopically evaluated from all animals in all groups, unless further evaluation was deemed to be scientifically unwarranted. Once all tissues in all groups had been evaluated, the incidences of the lesion in question were evaluated by using the Cochran-Armitage trend test. When there was a significant lack of fit (LOF < 0.05) for the Cochran- Annitage trend test, the Fisher’s exact test with a Bonferroni correction was used to compare concentration groups to their respective controls."

"Data were maintained separately by gender for the purpose of statistical analyses. Except for Bartlett’s test, all other significance was judged at p < 0.05."

Male Crl:CD BR Rat