PCB-Associated Changes in mRNA Expression in Killer Whales (Orcinus orca) from the NE Pacific Ocean

摘要

Killer whales in the NE Pacific Ocean are among the world's most PCB-contaminated marine mammals, raising concerns about implications for their health. Sixteen health-related killer whale mRNA transcripts were analyzed in blubber biopsies collected from 35 free-ranging killer whales in British Columbia using real-time quantitative polymerise chain reaction. We observed PCB-related increases in the expression of five gene targets, including the aryl hydrocarbon receptor (AhR; r~2 = 0.83; p < 0.001), thyroid hormone a receptor (TRot; r~2 = 0.64; p < 0.001), estrogen a receptor (ERa; r~2 = 0.70; p < 0.001), interleukin 10 (IL-10; r~2 = 0.74 and 0.68, males and females, respectively; p < 0.001), and metallothionein 1 (MT1; r~2 = 048; p < 0.001). Best-fit models indicated that population (dietary preference), age, and sex were not confounding factors, except for IL-10, where males differed from females. While the population-level consequences are unclear, the PCB-associated alterations in mRNA abundance of such pivotal end points provide compelling evidence of adverse physiological effects of persistent environmental contaminants in these endangered killer whales.