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SUMMARYThe enzymatic activities of NTPDase and 5′nucleotidase are important to regulate the concentration of adenine nucleotides, known molecules involved in many physiological functions. Therefore, the objective of this study was to evaluate the activity of NTPDase and 5′nucleotidase in serum and liver tissue of rats infected byFasciola hepatica. Rats were divided into two groups: uninfected control and infected. NTPDase activity for adenosine triphosphate (ATP) and ADP substrates in the liver was higher compared with the control group at 15 days post-infection (PI), while seric activity was lower. In addition, seric and hepatic samples did not show changes for 5′nucleotidase activity at this time. On the other hand, either NTPDase or 5′nucleotidase activities in liver homogenate and serum were higher at 87 days PI. Early in the infection, low NTPDase activity maintains an increase of ATP in the bloodstream in order to activate host immune response, while in hepatic tissue it decreases extracellular ATP to maintain a low inflammatory response in the tissue. As stated, higher NTPDase and 5′nucleotidase activities 87 days after infection in serum and tissue, probably results on an increased concentration of adenosine molecule which stimulates a Th2 immune response. Thus, it is possible to conclude thatF. hepaticainfections lead to different levels of nucleotide degradation when considering the two stages of infection studied, which influences the inflammatory and pathological processes developed by the purinergic system.

SUMMARYThe aim of this study was to evaluate the oxidative stress in serum and liver and adenosine deaminase (ADA) activity of cattle experimentally infected byFasciola hepatica. The group A consisted of five healthy animals (uninfected), and the group B was composed of five animals orally infected with 200 metacercariae ofF. hepatica.On days 20, 40, 60 and 80 post-infection (PI) serum was collected to measure oxidative stress variables. On day 100 PI, animals were humanely euthanized and liver samples were collected. Infected animals showed lower (P< 0·05) seric ADA activities on days 40 and 60 PI but higher (P< 0·05) in the liver tissue compared with uninfected animals. Seric and hepatic reactive oxygen species (ROS) were higher (P< 0·05) in infected compared with uninfected animals. Hepatic thiobarbituric acid reactive substances were higher (P< 0·05) in infected animals. Catalase and glutathioneS-transferase activities were lower in liver tissue of infected animals, while glutathione peroxidase was higher compared with uninfected (P< 0·05). In summary, we conclude that oxidative stress occurs in cattle experimentally infected byF. hepatica, mainly due to excessive ROS production in the course of fasciolosis, contributing to hepatic damage, and that increased in hepatic ADA activity may contribute to the inflammatory process.

SUMMARYThe aim of this study was to investigate the activities of important enzymes involved in the phosphoryl transfer network (adenylate kinase and creatine kinase (CK)), lactate dehydrogenase (LDH), respiratory chain complexes and biomarkers of cardiac function in rat experimentally infected byTrypanosoma evansi.Rat heart samples were evaluated at 5 and 15 days post-infection (PI). At 5 day PI, there was an increase in LDH and CK activities, and a decrease in respiratory chain complexes II, IV and succinate dehydrogenase activities. In addition, on day 15 PI, a decrease in the respiratory chain complex IV activity was observed. Biomarkers of cardiac function were higher in infected animals on days 5 and 15 PI. Considering the importance of the energy metabolism for heart function, it is possible that the changes in the enzymatic activities involved in the cardiac phosphotransfer network and the decrease in respiratory chain might be involved partially in the role of biomarkers of cardiac function ofT. evansi-infected rats.