The Status of Polychlorinated Biphenyls (PCBs) Extract from Zhanjiang Mangrove Sediments and the Effects on Tissue Structure and Inflammatory Cytokines in Zebrafish Liver.

Abstract

Polychlorinated biphenyls (PCBs) are released into the environment from a wide range of sources. The aim of the present study was to investigate the effect of the PCBs extracted from the Zhanjiang mangrove sediments on the immune function of zebrafish. The sediments were collected from 3 mangrove forest points in Zhanjiang (Guangdong Province, China), and the results showed that PCB153 was detected in the sediments of the Guangdong Zhanjiang Mangrove National Nature Reserve(MNNR) and Gaoqiao Mangrove Reserve(GMR), while PCB101, PCB112, PCB155, and PCB198 were detected in the sediments of the Leizhou Peninsula(LP). The zebrafish were exposed to different concentrations of PCBs, i.e., control group, positive control group (Aroclor1254; 10μg/L), low dose group (LD; 0.6μg/L), medium-dose group (MD; 3.0μg/L) and high dose group (HD; 15μg/L) for 14days. As compared to the control group, the liver index increased significantly in all PCB treated groups. The liver tissue structure was destroyed in all PCB-treated groups as compared to the control group. In addition, the relative mRNA expression of the target genes (IL-1β, IL-8, and TNF-α) was significantly expressed in each concentration group. Therefore, these findings suggest that exposure of zebrafish to PCBs can destroy the liver histology and increase the liver index and mRNA expression of inflammatory cytokines in a dose and time-dependent manner.