Seal Serum Offers Protection from Inflammation

Researchers looking into why seals don't experience damage to their lungs when they take a deep-sea dive found the answer in their blood serum. (Neil Smith Illustration, reproduced with permission from Journal of Experimental Biology doi:10.1242/jeb.178491)
Researchers looking into why seals don't experience damage to their lungs when they take a deep-sea dive found the answer in their blood serum. (Neil Smith Illustration, reproduced with permission from Journal of Experimental Biology doi:10.1242/jeb.178491)

Seal lungs can take a terrible pounding when one of the mammals leaves the surface. When the lungs collapse during deep descents in order to protect the animal, the delicate tissues incur damage as they are crushed, then suffer blood and oxygen flooding back when the animals return to the surface. In addition, the fragile tissues could suffer inflammation, which is usually triggered to heal any damage.

Yet a team of researchers from various institutions across the United States, including UConn’s Milton Levin, an assistant research professor of pathobiology and veterinary science, found no evidence of damage to pulmonary tissues in these deep-diving species.

Their study is published in the July 9 edition of Journal of Experimental Biology.

Weddell seals diving under the ice. (changehali via Wikimedia Commons)
Weddell seals diving under the ice. Researchers hope to apply their findings regarding the protection provided by seal serum to extend the survival of organs used in transplant surgery. (changehali via Wikimedia Commons)

Wondering how elephant seals and Weddell seals protect their lungs from the potentially damaging inflammatory response that should be triggered by the injuries to which the lungs are exposed when they make a deep dive, the team tested whether blood samples from the two species offered any protection from the effects of inflammation triggered by a bacterial toxin, lipopolysaccharide.

Impressively, the toxin triggered barely any inflammatory response in the seal blood, in contrast to human blood samples, which experience inflammation 50 to 500 times greater. And when the team added serum extracted from seal blood to mouse immune cells, the serum quenched the inflammatory response.

“These data suggest that seal serum possesses anti-inflammatory properties, which may protect deep divers from naturally occurring inflammatory challenges, such as dive-induced hypoxia-deoxygenation and lung collapse,” say the researchers. They would like to identify the protective compounds, in the hope of being able to use them to extend the survival of organs used in life-saving transplant surgery.

The study was funded by a grant from the Office of Polar Programs, NSF #1443554.

doi:10.1242/jeb.184937

Bagchi, A., Batten, A.J., Levin, M., Allen, K.N., Fitzgerald, M.L., Hückstädt, L.A., Costa, D.P., Buys, E.S., Hindle, A.G. (2018). Intrinsic anti-inflammatory properties in the serum of two species of deep-diving seal. Journal of Experimental Biology 221, doi:10.1242/jeb.178491.

kathryn.knight@biologists.com