Aim. To evaluate left ventricular myocardial structural remodeling in experimental type 1 diabetes mellitus (T1DM) and to assess the effects of L-arginine and N-acetyl-L-cysteine.

Materials and methods. The study involved 47 male Wistar rats. Type 1 diabetes mellitus was induced by streptozotocin (45 mg/kg). From week 6, rats received L-arginine or N-acetyl-L-cysteine (1.5 g/kg). ImageJ software was used to analyze cardiomyocyte area, nucleo-cytoplasmic ratio, and cell density.

Results. T1DM was found to cause pathological cardiomyocyte hypertrophy (area +17 %) alongside decreased cell density (-26 %) and suppression of the nuclear apparatus (nucleo-cytoplasmic ratio -10 %). L-arginine administration reduced perivascular infiltration but further decreased the nucleo-cytoplasmic ratio (-17 % compared to type 1 diabetes mellitus). N-acetyl-L-cysteine promoted nuclear area recovery (+34 % compared to type 1 diabetes mellitus) and stabilized cell density to control levels.

Conclusions. Experimental type 1 diabetes mellitus leads to pathological left ventricular hypertrophy with significant cardiomyocyte loss and disturbance of morphometric characteristics of nuclei with a decrease in nuclear-cytoplasmic ratio. The use of L-arginine attenuates the severity of perivascular inflammatory infiltration and reduces the nuclear-cytoplasmic ratio but does not eliminate muscle fiber fragmentation and cellular heterogeneity. N-acetyl-L-cysteine reverses pathological hypertrophic changes and restores nuclear apparatus.