Key result
Monocrotaline-induced PAH reduces right atrial isometric tension by ~59% in rats.
Why the study?
Pulmonary arterial hypertension leads to alterations in cardiac pump function, causing right-sided hypertrophy and heart failure.
Absolute Event Rate: 7.58% vs 18.63%
p-value: p=<0.05
In a rat model of monocrotaline-induced pulmonary arterial hypertension, right atrial contractility is more severely impaired than right ventricular contractility at both the molecular and multicellular levels.
Right atrial impairment predominates in this PAH model; leaves open human translation and therapeutic targeting.
Pulmonary arterial hypertension (PAH) leads to changes in the pump function of the heart and causes right-sided hypertrophy and heart failure. The study of the mechanical function of multicellular myocardial preparations was performed on isolated strips of the right atrium (RA) and trabeculae of the right ventricle (RV) of control (CONT) and monocrotaline-treated (MCT) male rats. The mechanical characteristics of the actin-myosin interaction were studied in the right-sided heart chambers from the CONT and MCT groups. For the first time, a comparative study of the contractile characteristics of myocardial preparations of both RA and RV in MCT-induced PAH at the molecular and multicellular levels was performed. For both RA and RV of MCT-treated rats, it was shown a decrease in the fraction of motile filaments and the maximum sliding velocity of actin and reconstituted thin filaments over myosin accompanied by a shift in α-/β-myosin heavy chains (MHC) ratio towards β-MHC. In the RA strips and RV trabeculae, a decrease in the maximum shortening velocity, the amplitude of isometric tension, the amount of work, and an increase in the end-systolic length were found. PAH leads to a greater drop in right atrial contractility than that of the ventricle.
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Gerzen et al. (2022) studied Pulmonary arterial hypertension (n=38). Monocrotaline vs. Saline was evaluated on Amplitude of isometric tension in right atrium (mN/mm²) (p=<0.05). Monocrotaline-induced pulmonary arterial hypertension significantly reduced the amplitude of isometric tension in the right atrium from 18.63 to 7.58 mN/mm² compared to control rats.
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