Renal lesions in Greenland sledge dogs (Canis familiaris) exposed to a natural dietary cocktail of persistent organic pollutants

Abstract

Persistent organic pollutants such as Polychlorinated biphenyls (PCB) and dichloro diphenyl trichloroethane (DDT) are known to exert various adverse health effects in wildlife mammals. The impact from dietary intake of minke whale (Balaenoptera acutorostrata) blubber high in organohalogen and other chemical contaminants on renal morphology and function was investigated via a controlled study on West Greenland sledge dogs (Canis familiaris). Our results showed significantly higher frequencies of glomerular, tubular, and interstitial lesions in the exposed group. Furthermore, higher urine protein : creatinine ratio and plasma urea levels were found in the exposed group, which indicated a negative impact on kidney function via tubular and glomerular dysfunctions. The lesions were similar to those observed in top predator marine species–such as seals and polar bears–and humans exposed via diet to persistent environmental pollutants. The lesions may have impacts on the overall health of these animals. It is reasonable to suggest that chronic exposure to organic pollutants via a country diet of high trophic level marine organisms may have an impact on renal morphology and function in Arctic apex predators in general as well as Inuit people.

Keywords:

• Kidney
• minke whale blubber
• sledge dogs
• West Greenland
• renal morphology
• captive cohorts
• PCBs
• organochlorine pesticides
• PBDEs
• mercury

Acknowledgment

We thank the Danish Cooperation for Environment in the Arctic, Natural Science and Engineering Research Council (NSERC) Canada (to R.J. Letcher) and Lundbeck Foundation for funding, and Royal Canin for providing reduced prices for pellets and Kruuse donated clinical equipment (centrifuge). Thomas Dau Rasmussen, Anne Silverbau, Mikael and Jane Rasmussen, Jørn Breinholt and Jens Kjeldsen are acknowledged for their help and skilled daily dog handling. We also thank Wouter Gebbink (NWRC/CWS, Environment Canada) in Dr Letcher's research group for assisting with the OHC analysis. Two anonymous reviewers are acknowledged for valuable inputs to the manuscript. A conflict of interest was not reported.