HISTOLOGICAL AND HISTOCHEMICAL CHARACTERISTICS OF RAT MYOCARDIUM IN CADMIUM TOXICOSIS

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Carcinogenic effects of cadmium on lungs, testicles and prostate are well known, so as cumulative and toxic effects on kidney, liver and bones; however, there have not been many published articles about the effects of cadmium on myocardium. The aim of this study was to estimate the morphological changes in rat myocardium chronically treated by cadmium. The study was carried out on male albino Wistar rats (n=30, age=35-37 days, body mass 120g +/- 10g). The animals were raised in controlled laboratory conditions and provided with standard laboratory rat food and tap water ad libitum. The rats were divided into two groups: ten animals composed the control group and did not undergo any treatment. The 20 experimental rats were exposed to 10mg of CdCl2 /L drinking water for 90 days. After 90 days, all animals were victimized and after the macroscopic inspection of the heart, myocardial tissue was routinely processed and embedded in paraffin. Sections 5 micrometers thick were stained by HE method and histochemical PAS-AB (pH 2, 5), Masson trichrome method for demonstrating collagen fibers and Toluidine blue for mast cells identification. Cross-striated banding pattern of cardiac cells was ruined. Noticeable atrophy and hydropic degeneration of subendocardial localized cardiac cells were found, with the focal presence of myocytolysis. Endothelial cell hyperplasia and edema of the intima were present on arteriolar type blood vessels causing the focal subocclusion. Fibrocytes, histiocytes and mast cells were numerous, perivascularly localized. Mast cells were polymorphic, larger than normal, oval and mostly degranulated. Instead of scanty endomysium, there is a noticeable interstitial fibrillar fibrosis with few fields of collagen in all myocardium layers between cardiac cells, which is particularly prominent around the larger blood vessels. Cadmium has pronounced vasculotropic properties causing morphological changes of cardiomyocytes, myocardial interstitial fibrillar collagen network and on the heart small blood vessels. Acta Medica Medianae 2013;52(2):15-22.