Original Article Use of Fluorescence in a Modified Disector Method to Estimate the Number of Myocytes in Cardiac Tissue

Background: Conventional disector methods currently require considerable financial, technical and operational costs to estimate the number of cells, including cardyomyocytes, in a 3D area. Objective: To use fluorescence microscopy in a modified disector method to determine the number of myocytes in cardiac tissue in normal and pathological conditions. Methods: The study employed four-month-old male Wistar rats with weight of 366.25 ± 88.21g randomized in control (CG, n=8) and infected (IG, n=8) groups. IG animals were inoculated with T. cruzi Y strain (300,000 trypomastigotes/50g wt). After eight weeks, the animals were weighted and euthanized. The left ventricles (LV) were removed for stereological analysis of numerical density of cardiomyocytes (Nv[c]) and total number of these cells in the LV (N[c]). These parameters were estimated using a fluorescent disector (FD) and compared with the conventional optical (OD) and physical (PD) disector methods. Results: In both disector methods, IG animals presented significant decrease of Nv[c] and N[c] compared to CG animals (P< 0.05). There was no significant difference in these variables despite the disector method applied in CG and IG animals (P> 0.05). A strong correlation, equal or above 96%, was obtained between FD, OD and PD. Conclusion: The FD method seems to be equally reliable to determine Nv[c] and N[c] in normal and pathologica