Toxicity study of maternal transfer of polychlorinated biphenyls and diethyl phthalate to 21-day-old male and female weanling pups of Wistar rats

Abstract

Polychlorinated biphenyls (PCBs) are environmental pollutants known to act as xenoestrogens. PCBs and diethylphthalate (DEP) are ubiquitous environmental pollutants because both are used as plasticizers and in various other industrial applications. Therefore, a study was undertaken to evaluate the interactive toxicity of DEP and PCB in 21-day-old male and female pups of Wistar rats. Healthy young male and female albino rats of Wistar strain weighing 75-100g (6-7 weeks old) were randomly assigned to four groups of six each. Group I male and female rats were fed a normal diet and water ad libitum. Group II and III male and female rats were given PCB (Clophen A60) and DEP dissolved in corn oil mixed with the diet at 50 mg/kg of the diet (2.85 mg/kg body wt) individually to each group. Group IV male and female rats received a mixture of DEP and PCB (Clophen A60), each dissolved in corn oil mixed with the diet at 50 mg/kg of the diet (2.85 mg/kg body wt). Hundred days after the treatment, females were mated with males for 10 days. Exposure to DEP and PCB was continued throughout mating, gestation until termination at weaning, which was 150 days of total treatment period of adults. The pups from each group were then segregated on the basis of their sex. Six male and female pups each (approx. 21 days old) from each group were chosen randomly and were killed for toxicity study. Liver-to-body weight ratio showed significant increase in the male and female pups of PCB- and PCB+DEP-treated rats, whereas male pups of DEP alone treated rats showed significant increase and female pups showed significant decrease as compared to controls and other treated groups. Significant increase in liver and serum lactate dehydrogenase (LDH) and acid phosphatase (ACP) activity in the male and female pups of the three treated groups was observed. Alkaline phosphatase (ALP) activity was significantly increased only in the serum of male and female pups of the three treated groups, whereas significant decrease in the liver of male pups of the three treated groups. In the female pups, significant decrease in liver ALP was observed only PCB- and PCB+DEP-treated groups. Histology of liver showed severe vacuolation and steatosis in the hepatocytes of PCB-treated male and female pups and in PCB+DEP-treated group, vacuolation, and steatosis was much more predominant as compared to the PCB and DEP alone treated groups. DEP alone treated groups, both male and female pups showed mild vacuolations in the liver. A synergistic interactive toxic effect of PCB and DEP was evident in both male and female pups in the following study.