In vivo assessment of oxidative stress in heart cells of Cirrhinus mrigala (Hamilton, 1822) challenged with sublethal doses of Aeromonas hydrophila

Abstract

Experiment was performed to study the effect of Aeromonas hydrophila MTCC 646 on the heart of Cirrhinus mrigala (Hamilton, 1822) . The in vivo innate immune response was also monitored in these fishes. Fishes were inoculated with 3 asymptomatic doses (2x105, 2x106 and 2x107 CFU ml-1) intraperitoneally (i.p.) @ 0.5 ml 100 g-1. Dose dependent pattern of change was observed in the immune biomarkers chosen for the study. Histopathology revealed endocarditis and cell death identified as apoptosis. The percentage contribution of late apoptotic cells was 0.36% after 7 days in fish heart exposed to the highest dose of bacteria which was reduced to 0.01% after 30 days. Oxidative stress and dosage were directly proportional. The oxidised dichloro fluorescein peak was about 4.05 fold more than the control samples, after 7 days with respect to the highest dose and immune responses helped to decrease the mean peak to 1.02 after 30 days, signifying recovery of phagocytic activity, which is a part of the reticulo-endothelial system. This work presents an insight into the immune response and the results analysed statistically show that there was significant difference between percent population of early apoptotic cells (p<0.05) collected after 7 days and 30 days duration with respect to all the three doses.