ARKHANGELSK, January 20. /TASS/. Scientists identified dynamics of local immune protection changes in Arctic expeditions' participants. During voyages of the Arctic Floating University, physiologists assessed the number of microbes on the expeditions' participants' oral epithelium, Alexandra Elfimova, a senior researcher at the Tkachev Laboratory of Endocrinology at the Federal Research Center for Integrated Arctic Studies (the Russian Academy of Sciences' Urals Branch), told TASS.

"We have managed to study the oral epithelium's sorption activity in terms of the number of microbes on epithelial cells surface," she said. "We did it during two expeditions, and, having merged results, we could see its significant decrease in the middle of the voyages."

The Arctic Floating University's expeditions are usually about three weeks long. In the middle of those expeditions, participants go ashore the polar archipelagos, work intensively, with heavy loads, including physical ones. They remain in extreme conditions: the polar day, the cold, and waves at sea.

"The number of microbes on the epithelium surface increases in the middle of the voyage, that is, the epithelium sorption activity decreases. Most likely, this is due to a decreased content of immunoglobulin A, which protects the "entrance gate" from infection," she added. By the end of the voyage, the epithelium sorption activity returns to usual rates, she said.

Immunoglobulin A is a key indicator of local immune protection, and its lower level leads to an imbalance of the microflora that forms the oral mucosa protective biofilm. The researchers plan to determine additionally the content of pro-and anti-inflammatory cytokines in saliva samples. These are protein signaling molecules that stimulate or suppress inflammatory reactions.

The work is carried out jointly with the Environmental Immunology Laboratory. Noninvasive diagnosis of immune protection is important during Arctic voyages, therefore it is promising to study and compare general and local immunity indicators and identify saliva markers that reflect immune protection's effectiveness. "The assessment and comparative analysis of general and local immunity indicators will provide scientific justification for non-invasive assessment of how effective is adaptation to conditions of Arctic voyages to develop recommendations on using plant adaptation and other preventive measures to increase adaptive reserve in participants of Arctic marine expeditions and their successful activities," the scientist said in conclusion.