Histological Evaluation of Myocarditis

Tissue sections were fixed in 10% buffered formalin for 24 h, dehydrated in absolute ethanol, cleared in xylene, and embedded in paraffin. Five-micron tissue-sections were stained with hematoxylin and eosin, and evaluated by light microscopy using an Olympus BX-15 microscope equipped with a digital camera. In general, we analyzed each tissue-section for >10-microscopic fields (100× magnification), and examined three different tissue sections/mouse (4 mice/group) to obtain a semi-quantitative score of parasitic pseudocysts (foci). Myocarditis (presence of inflammatory cells) was scored as 0 (absent), 1 (focal or mild with ≤1 foci), 2 (moderate with ≥2 inflammatory foci), 3 (extensive with generalized coalescing of inflammatory foci or disseminated inflammation), and 4 (diffused inflammation with severe tissue necrosis, interstitial edema, and loss of integrity) [38] (link). Inflammatory infiltrates was characterized as diffused or focal depending upon how closely the inflammatory cells were associated [39] (link).