Hydrogen-rich saline mitigates pressure overload-induced cardiac hypertrophy and atrial fibrillation in rats via the JAK-STAT signalling pathway

Objective To investigate if hydrogen-rich saline (HRS), which has been shown to have antioxidant and anti-inflammatory properties, could mitigate cardiac remodelling and reduce the incidence of atrial fibrillation (AF) in the rat model of cardiac hypertrophy. Methods Pressure overload was induced in rats by abdominal aortic constriction (AAC). The animals were separated into four groups: sham; AAC group; AAC plus low dose HRS (LHRS); AAC plus high dose HRS (HHRS). The sham and AAC groups received normal saline intraperitoneally and the LHRS and HHRS groups received 3 or 6 ml/kg HRS daily for six weeks, respectively. In vitro research was also performed using cardiotrophin-1 (CT-1)-induced hypertrophy of cultured neonatal rat cardiomyocytes. Results Cardiac hypertrophy was successfully induced by AAC and low and high dose HRS mitigated the pressure overload as shown by lower heart and atrial weights in these treatment groups. AF incidence and duration of the HRS groups were also significantly lower in the HRS groups compared with the AAC group. Atrial fibrosis was also reduced in the HRS groups and the JAK-STAT signalling pathway was down-regulated. In vitro experiments showed that hydrogen-rich medium mitigated the CT-1-induced cardiomyocyte hypertrophy with a similar effect as the JAK specific antagonists AG490. Conclusions HRS was found to mitigate cardiac hypertrophy induced by pressure overload in rats and reduce atrial fibrosis and AF which was possibly achieved via inhibition of the JAK-STAT signalling pathway.