[A histological analysis of the changes experimentally induced by cadmium in cardiac muscle tissue by a computerized method of image analysis].
OBJECTIVE
To study the distribution of myocardial structural elements in a univentricular experimental model (Halobatrachus didactylus) and the changes induced by acute exposure to a sublethal concentrations of cadmium.


METHODS
15 specimens of H. didactylus (marine teleost) were divided in three groups: CTRL: the control group, the fish were injected with a saline solution; 24 H: 1 mg/kg of cadmium chloride was injected and fish were sacrificed after 1 day post injection; 7 D: fish where subjected to the same cadmium concentration and sacrificed after 7 days post injection.


METHODS
Histological sections (5 microns) of ventricle were coloured by PicroSirius method and used to determine the fraction area occupied by the several myocardium structural elements, using specific software Optimas Bioscan 5.2.


RESULTS
The different structural elements of H. didactylus myocardium displayed in different ways and its distribution along the ventricular wall remained unchanged on exposure to cadmium. The structural elements of H. didactylus myocardium showed a characteristic pattern: collagen type I revealed a heterogeneous distribution, with fractional area values greater in epicardial and endocardial layers; collagen type III, has a homogeneous distribution with the myocardial wall thickness with lesser fractional area values than collagen I; cardiac muscle tissue showed a tendency to occupy a greater fractional area in the epicardial-endocardial region. Cadmium toxicity resulted in an increase in the fractional area occupied by muscle tissue to the detriment of the area occupied by the intertrabecular spaces (lacunae), with no alterations in the other structural components.


CONCLUSIONS
On our H. didactylus fish model, cadmium may have induced a myocardial edema which resulted in an increase in the fractional area occupied by muscle tissue, with no alterations in other structural components of the myocardium or in the relative ventricular mass.
Coucelo
J M
JM
Laboratório de Fisiopatologia, U.C.T.R.A., Universidade do Algarve, Faro.
Joaquim
N
N
Correia
V
V
Azevedo
J
J
Coucelo
J A
JA
D000818:Animals; D019256:Cadmium Chloride / Q000633:toxicity*; D003094:Collagen / Q000187:drug effects / Q000378:metabolism; D005399:Fishes; D006321:Heart / Q000187:drug effects*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D012984:Software; D013997:Time Factors
D003094:Collagen; D019256:Cadmium Chloride
Análise histológica de alterações induzidas experimentalmente por cádmio no tecido muscular cardíaco através de método computadorizado de análise de imagens.