Effects of lactational exposure to non-planar PCB-155 and planar PCB-169 on body weight gain and craniofacial growth in rat offspring

Abstract

The adverse effects of two polychlorinated biphenyls (PCBs), non-planar PCB-155 and planar PCB-169, individually and in combination, on body weight gain and craniofacial growth in rat offspring lactationally exposed to PCBs during the early postnatal period were investigated. Lactating adult Wistar rats (n=15) were intraperitoneally administered a total of 12 mg/kg b.w. PCB-155 (group 1, n=4), 3 mg/kg b.w. PCB-169 (i.e., 90 mg toxic equivalents (TEQ)/kg b.w.) (group 2, n=4), or PCB-169 and PCB- 155 together (group 3, n=3). The fourth group (n=4) served as a control. Offspring were sacrificed on postnatal days (PNDs) 9 and 22. Body weights and craniofacial dimensions were recorded. On PND 9, all of the exposed offspring weighed less (p≤0.001) than the control group, and group 2 (p≤0.001) and 3 (p≤0.01) weighed less than group 1. On PND 22, only groups 2 and 3 weighed less than the control group (p≤0.001). Narrower neurocranium was observed on PND 9 in groups 1 (p≤0.01), 2 (p≤0.05) and 3 (p≤0.001). Skulls were shorter in groups 2 (p≤0.001) and 3 (p≤0.01), and this reduction persisted until PND 22 (p≤0.001). On PND 22, rounder skulls were observed in groups 2 (p≤0.001) and 3 (p≤0.05), and mandibular length was reduced (p≤0.001). The data suggest that PCB-155 may have an additive effect with PCB-169 on growth reduction. In conclusion, lactational exposure to PCB-155 and PCB- 169 negatively affected body weight gain and craniofacial growth in rat offspring until PND 9, while the adverse effects of PCB-169 were more potent and persisted until PND 22.