Interactions between the levels of NO, ROS and HO-1 activity and apoptosis Mononuclear cells from peripheral blood and spleen leukocytes dogs with Visceral Leishmaniasis

Author(s)

Aline Aparecida Correa Leal

• Document type: Master's Dissertation
• Press: Araçatuba. 2016-07-07.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária. Araçatuba
• Defense date: 2016-05-06
• Advisor: Valeria Marçal Felix de Lima

Abstract

Leishmania are obligate intracellular protozoan that infects phagocytic mammalian cells causing canine visceral leishmaniasis (CVL). Because they have an intense cutaneous parasitism, infected dogs have key role in disease transmission. To survive in the host, the Leishmania are able to develop escape mechanisms by changes in phagocytic cell responses, such as the NO and the ROS responsible for the death of intracellular parasites. The HO-1 may also be involved in regulating the immune response, but their role in canine visceral leishmaniasis is not yet clear. The excessive production of NO, ROS and HO-1 can be detrimental and to be related to immune dysregulation and apoptosis in LVC. So this study aimed to investigate the levels of ROS, NO and HO-1 activity in mononuclear cells of peripheral blood leukocytes and spleen and its correlation with cell apoptosis. For this they used blood mononuclear cells and spleen leukocytes from infected and healthy dogs. Cells were isolated and cultured for 24 hours following probes were incubated with NO or ROS and cell apoptosis was determined. All analyzes were performed by flow cytometry. After lysis of the cells in culture, HO-1 activity in cell lysate was determined by a colorimetric method. Oxidative metabolism was reduced and the apoptosis rate of increased blood mononuclear, influenced by ROS. The levels of ROS and NO were decreased in leukocytes from the spleen of infected dogs, and increased apoptotic rate was observed in spleen leukocytes from infected dogs. The activity of HO-1 was obtained in both reduced blood monucleares as in the splenic leukocytes from infected animals compared with healthy animals, but was not correlated with apoptosis. We concluded that the apoptosis-inducing mechanisms differ at sites of infection, or spleen reactive oxygen and nitrogen are involved with the inhibition of cell death, however hemooxigenase activity may play a role in apoptosis. (AU)

• FAPESP's process: 14/08931-6 - Interaction between the levels of ROS, NO and activity of HO-1 with apoptosis of mononuclear cells from peripheral blood and spleen of dogs with visceral leishmaniasis
• Grantee: Aline Aparecida Correa Leal
• Support Opportunities: Scholarships in Brazil - Master