"Intravital Investigations in Dams and Litters

Dams of groups 01–04 were weighed on days 1, 4, 6, 10, 15, and 20 p.c. as well as on days 1, 4, 8, 15, 21, and 22 p.p. (= day of weaning) and dams of groups 05–06 were weighed on days 1 and 19 p.c. as well as on the days of milk collection. Number of offspring and the occurrence of any dead pups were recorded for all groups. In groups 01–04,

litter weight (separately for males and females) was determined on days 1, 4, 8, 15, and 21 p.p. One male and one female pup of each litte r of groups 01–04 were randomly selected for necropsy and clinical chemistry upon weaning and were weighed individually on day 22 p.p. Individual food consumption in groups 01–04 was determined on days 6, 10, 15, and 20 p.c. as well as on days 1, 4, 8, 15, and 22 p.p. In groups 05 and 06, food consumption was recorded on days 8, 15, and 21 p.p.

Postmortem Investigations

At the end of the study, all animals were sacrificed by CO2 overdose and subsequent exsanguination. Necropsy was performed in all dams and in one male and one female pup of each litter of groups 01–04. The number of implantation sites was macroscopically determined in the dams without staining of the uterus, and “postimplantation loss” was determined as (number of implantation sites) – (number of live pups day 1 p.p.). Terminal body weights and liver weights were determined. Relative organ weight data were computed.

Statistical Analysis

Differences between groups were considered casewise as statistically significant for p < .05. Maternal and offspring weights, organ weights (absolute and relative), data on milk production, clinical chemistry data, and analytical data were analyzed using analysis of variance. If the group means differed significantly with this method, the means of the treatment groups were compared with the mean of the control group 01 using Dunnett’s modification of the t-test. The incidence of dead offspring was analyzed using the two-tailed Fisher test with the litter as the basic unit. Postnatal data were analyzed using a two-factor analysis of variance to differentiate between pre- and postnatal influences of the substance exposure. If no clear interactions were found by this procedure, a two-factor analysis without interaction was performed for easier interpretation of the results. In all instances, the dam or litter was used as the basic unit. Data of animals without implantation sites were excluded from statistical treatment. All statistics were run on the SAS system 6.08 on a VAX microcomputer."

"Maternal and litter data before fostering are summarized in Table 3. No differences in the number of implantation sites were observed between the different groups. There were no treatment-induced effects on the number of liveborn pups, the “postimplantation loss,” the number of dams with “postimplantation loss,” and the mean pup weight and mean litter weight on day 1 p.p. The only findings were a dead pup showing ectopic omphalocele in group 03 and a stillborn pup with generalized edema and aplasia of the tail in group 06."

P0 Female Sprague-Dawley Rats (HCFC-123/clean air)