Effects of the ultraviolet radiation on the immune response in broad- snouted caiman (Caiman latirostris) injected with lipopolysaccharides of Escherichia coli. Report of advance.

L. FERNANDEZ, G.L. POLETTA, P.S. AMAVET, P.A. SIROSKI

Manaos, Brasil

Congreso; 20th Working Meeting of the Crocodile Specialist Group, IUCN-SSC; 2010

Crocodile Specialist Group (SSC-IUCN)

The sun emites ultraviolet radiation (RUV) that are necessary to many vital processes of the organisms. RUV exposure is essential for development and reproduction, being the synthesis of vitamin D3 one of its most important benefits. Overexposure to RUV might have adverse effects such as immune suppression, which could debilitate recognition of some antigens after a few days of the irradiation. Some researches assert that the damages caused by this type of radiation might have tremendous influence on the health of populations. Although UV-B wavelength range can exert a positive influence on diverse biological effects, but excessive UVB radiation exposure interferes with the normal function of the immune system in both animals and human beings. Lipopolysaccharide (LPS) is a major component of the wall of Gram negative bacteria. The lipid portion of the LPS contains a toxic substance, the Lipid A, that is recognized by the immune systems of higher eukaryotes and causes an inflammatory reaction. Twenty seven broad-snouted caiman (3 months old) will be used for this study. Eggs will be harvested from 3 different wild nests and artificially incubated under controlled conditions. The caiman will be maintained under different UVR wavelength ranges (UV - A and UV-B) during the 60 days experiment. The UV exposure will be of 12 hours per day. For each treatment group, we will evaluate animal growth (weight, total length and snout – vent length), as well as immune system function by total and differential peripheral leukocytes counts, serum complement activity and concentrations of total and fractions proteins. We suspect that overexposure to RUV will lead to an immunesuppressive effect, reducing the immune response of Caiman latirostris  due to E. coli LPS.