Leukogram and cortisol parameters in Swiss mice experimentally infected withAngiostrongylus costaricensis

Abstract

This study describes changes in haematological parameters, cytokine profile, histopathology and cortisol levels in Swiss mice experimentally infected with Angiostrongylus costaricensis. Twenty-eight Swiss mice were divided into two groups (G1 and G2) of 14 animals each. In each group, eight animals were infected orally with ten third-stage larvae of A. costaricensis and six were used as a control group. The mice of groups G1 and G2 were sacrificed 14 and 24 days after infection, respectively. Samples were collected for histopathological and haematological analyses and determination of the cytokine profile and cortisol levels. Granulomatous reaction, eosinophilic infiltrate and vasculitis in the intestinal tract, pancreas, liver and spleen were observed with varying intensity in infected animals. Our results showed that the mice developed normocytic and hypochromic anaemia, and that the histopathological lesions caused by the experimental infection influenced increases in cortisol, neutrophil and monocyte levels. In addition to this, we detected increased interleukin-6 and tumour necrosis factor alpha levels in the infected animals.

Relationship between histopathological lesions and oxidative stress in mice infected with Angiostrongylus costaricensis

“…The results obtained in the present study complement what was done by our team, by Hermes et al (2020) and Benvegnú et al (2021). This indicated that the degree of inflammatory lesions is a result of parasite migration during the development of the biological cycle and is not related to the dose of infection.…”

“…During this same period, there was the presence of a mild or moderate eosinophil infiltrate in the liver and intestine, and this may have led to the reduction in the serum levels of NPTs. In an experiment carried out by Benvegnú et al (2021), 28% of the infected animals in their G1 (14 dpi) presented liver nodules and 37.5% of the infected animals showed pancreatitis.…”

“…The ‘three Rs principle’, that is, reduction, replacement and refinement, was followed in this experiment. This principle envisages that, whenever possible, data obtained through previous animal experimental studies should be used, and it encourages reduction of animal use when there is no real need for this (Benvegnú et al , 2021).…”

“…Blood samples were collected at 07:30 am through intracardiac puncture, with previous anaesthesia of the animals with Isoflurane (Isoforine®). The blood was stored in tubes with ethylenediaminetetraacetic acid and the serum was separated by centrifugation at 2500 rotations per minute for five minutes and was frozen at −70°C until use (Benvegnú et al , 2021).…”

“…The slides were prepared for histological analysis from three sections and stained with haematoxylin and eosin, for later analysis under an optical microscope. The following aspects were investigated: (a) presence of infarction; (b) identification of eggs, larvae and adult worms; (c) presence of eosinophilic infiltrate (focal, multifocal and diffuse); (d) granuloma formation (focal, multifocal and diffuse); and (e) characterization of vasculitis, thrombosis and pancreatitis (Hermes et al , 2020; Benvegnú et al , 2021) (figs 1–3).

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