N-Acetylcysteine Ameliorates Experimental Autoimmune Myocarditis in Rats via Nitric Oxide

Area of Science:

• Cardiovascular Research
• Immunology
• Oxidative Stress

Background:

• Oxidative stress is implicated in the pathogenesis of myocarditis.
• Experimental autoimmune myocarditis (EAM) serves as a model to study inflammatory heart disease.

Purpose of the Study:

• To investigate the therapeutic effects of N-acetylcysteine (NAC), an antioxidant, on EAM in a rat model.
• To elucidate the role of the nitric oxide (NO) system in NAC's protective effects against myocarditis.

Main Methods:

• EAM was induced in rats using porcine myosin.
• Rats received daily intraperitoneal injections of NAC (20 mg/kg/d) or saline from day 1 to 21.
• Additional groups were treated with NAC combined with N(G)-nitro-l-arginine methylester (l-NAME) or its inactive enantiomer, d-NAME, to assess the involvement of nitric oxide synthase (NOS).

Main Results:

• NAC treatment significantly improved cardiac pathology and reduced superoxide production in EAM rats.
• The beneficial effects of NAC were diminished when co-administered with l-NAME, but not d-NAME, indicating a role for the NO system.
• NAC reduced intercellular adhesion molecule 1 expression, increased myocardial c-kit(+) cells, and tended to reduce inflammation-induced left ventricular mass.

Conclusions:

• N-acetylcysteine (NAC) ameliorates myocardial injury in a rat model of experimental autoimmune myocarditis.
• The protective mechanisms of NAC involve the nitric oxide (NO) system.