Meeting Abstract
During the reproductive season, anuran males call to attract females for mating. This activity result in transient increase of corticosterone (CORT) plasma levels in order to recruit energy stores to sustain this energetically expensive activity. Additionally, under stressful situations that last for extended periods of time, such as food shortage, habitat fragmentation, and pollution, the plasma CORT levels can chronically increase. Acute and chronic elevation of CORT can modulate immune response, affecting how individuals deal with pathogens and injuries. Acute CORT levels are often associated with immunoenhancing effects while chronically elevated levels of CORT is considered immunosuppressive. The objective of this study is to understand how chronic and acute elevation of CORT plasma levels affect wound healing, an integrative immune response, in the American Bullfrog during their reproductive season. Forty males of were bought from a commercial farm and acclimated for seven days in individual plastic boxes, at the University of Sao Paulo, São Paulo, Brazil. Thereafter, individuals were divided into 4 groups: 1) Placebo, which received sesame oil daily; 2) Acute CORT, which received a daily transdermal CORT application (1.0µg); 3) Operated placebo, which received 3 subcutaneous empty silastic tubes (1 x 0,2 cm each); and 4) Operated chronic CORT, which received 3 subcutaneous silastic tubes filled with powder CORT. After the animals recovered from the surgery of silastic tube implant (7 days), all frogs were punctured in the leg with a biopsy needle. The wound was photographed and measured every 2 days in a stereomicroscopy. Blood samples were collected after acclimation, 6 days after surgery; and 6, 13, and 20 days after the biopsy in order to measure CORT and androgens plasma levels. The wound healing rate will be compared between groups and correlated with CORT plasma levels.
