Pathologically, in the present study, cardiac interstitial fibrosis and perivascular fibrosis and cardiomyocyte hypertrophy were more frequently observed in both the WKY+ELS and SHR+ELS groups as compared with the WKY+NS and SHR+NS groups, respectively (Fig 7), suggesting that an excessively low salt diet accelerates cardiac interstitial fibrosis and perivascular fibrosis and cardiomyocyte hypertrophy through activation of (P)RR and angiotensin II AT1 receptor and subsequent activation of ERK1/2 and TGF-ß, and activation of p38 MAP kinase and HSP27. The gene discussed is MAPK3; the disease is Interstitial cardiac fibrosis.