Histochemical evaluation of T-2 toxin-induced cardiotoxicity in rats: Semiquantitative analysis

Abstract

In this study female Wistar rats were treated with T-2 toxin (1 LD50 0.23 mg/kg sc) and sacrificed on days 1, 3, 5, 7, 14, 21, 28 and 60 after the treatment. Control groups of rats were treated by saline (1 ml/kg 0.9% NaCl). At each time-schedule, control groups of animals were sacrificed, too. Pathohistological alterations of the heart were evaluated in whole visual fields stained by haematoxylin and eosin (HE), periodic acid- -Schiff's (PAS), Masson-Trichrom's (MT) and Giemsa (GIM) methods. The changes observed were scored by using semiquantitative grading scale. The heart alterations detected in T-2 toxin-treated animals ranged from focal parenchymal or hyaline degeneration (HE = 2.5 - 4.0; p lt 0.05 vs. control) to diffuse necrosis of muscle cells (HE = 5.0; p lt 0.05 vs. control and 1st day after T-2 treatment). The myofibrils were slightly PAS-positive during the first week of the study (PAS = 2.0 - 3.2; p lt 0.05 vs. control and 1st day after T-2 treatment), while a diffuse distribution of glycogen granules in endo- and perimisium were observed from day 21 to 60 in the whole heart' tissue (PAS = 4.0; p lt 0.05 vs. control and 1st day after T-2 treatment). Massive hemorrhagic foci associated with diffuse accumulation and degranulation of MCs were the most intensive from day 28 to 60 of the study (MT = 5.0; p lt 0.05 vs. control and 1st day after T-2 treatment). During the whole study period, irregular distribution of glycogen granules, intensity and total number of haemorrhages were in correlation with the degree of heart structural lesions, which showed the highest coefficient of correlation (r = 0.8750; p lt 0.001). Our results indicate that basic histohemical methods can be a useful tool for evaluation of T-2 toxin-induced cardiac damage, which is probably a result of complex inflammatory mechanisms, eventually leading to vascular lesions and myocardial necrosis, as well as for some potential cardioprotectors in the future.

U ovom radu su ispitani toksični efekti na srcu Wistar pacova akutno trovanih T-2 toksinom. Životinje, jednokratno tretirane T-2 toksinom u dozi od 0,23 mg/kg sc (1 LD50), žrtvovane su 1, 3, 5, 7, 14, 21, 28. i 60. dana posle aplikacije otrova. Kontrolne grupe životinja tretirane su fiziološkim rastvorom (1 ml/kg 0,9% NaCl) i žrtvovane u istim vremenskim intervalima. Procena patohistoloških promena izvršena je na uzorcima tkiva srca, bojenih standardnim histohemijskih metodama: hematoksilin i eozin (HE), Gimza (GIM), perjodna kiselina Schiff-ov reagens (PAS) i Masson trichrom (MT), primenom semikvantitativne analize. U srcu pacova tretiranih T-2 toksinom uočene su promene od fokalne parenhimatozne i hijaline degeneracije miofibrila (HE = 2,5-4,0; r lt 0,05 u poređenju sa kontrolom) do fokalne ili difuzne nekroze mišićnih ćelija (HE = 5,0; r lt 0,05 u poređenju sa kontrolom i 1. danom posle aplikacije T-2 toksina). Tokom prve nedelje ispitivanja miofibrile su bile blago PAS-pozitivne (PAS = 2,0-3,2; r lt 0,05 u poređenju sa kontrolom i 1. danom posle aplikacije T-2 toksina), dok je difuzna distribucija granula glikogena u endo- i perimizijumu zapažena od 21. do 60. dana (PAS = 4,0; p lt 0,05 u poređenju sa kontrolom i 1. danom posle aplikacije T-2 toksina). Masivna hemoragična polja, okružena mnogobrojnim inflamatornim ćelijama, naročito su izražena u periodu od 28. do 60. dana ispitivanja (MT = 5,0; p lt 0,05 u poređenju sa kontrolom i 1. danom posle aplikacije T-2 toksina). Tokom celog perioda ispitivanja, nepravilna distribucija granula glikogena, intenzitet krvarenja i ukupan broj mastocita su bili u korelaciji sa stepenom oštećenja tkiva srca (r = 0,8750; p lt 0,001). Dobijeni rezultati su potvrdili ranije iznetu tezu da su kardiotoksični efekti T-2 toksina verovatno rezultat kompleksnih inflamatornih mehanizama.