The Role of the NOD1/Rip2 Signaling Pathway in Myocardial Remodeling in Spontaneously Hypertensive Rats

BACKGROUND Chronic hypertension changes the function and structure of the heart and blood vessels. This study aimed to explore the role of the NOD1/Rip2 (nucleotide-binding oligomerization domain 1/receptor-interacting protein 2) signaling pathway in myocardial remodeling in spontaneously hypertensive rats (SHRs). MATERIAL AND METHODS Blood pressure was measured using a tail cuff. The cardiac structure was observed using echocardiography. Slices of the myocardium were stained with hematoxylin and eosin. The expression of NOD1 and Rip2 was detected using real-time polymerase chain reaction, western blot, and immunohistochemistry. The content and distribution of collagen in the myocardium were observed using Van Gieson staining. Enzyme-linked immunosorbent assay was used to detect the interleukin-1 (IL-1) concentrations. SHRs were treated with the NOD1 agonist iE-DAP and NOD1 inhibitor ML130. RESULTS The NOD1 agonist increased blood pressure in SHRs, and the NOD1 inhibitor decreased blood pressure; the interventricular septum thickness (IVST) and left ventricular posterior wall thickness (LVPWT) of the agonist-treated group were thicker than those of the control group, and the antagonist exerted the opposite effects. The levels of the NOD1 and Rip2 mRNAs and proteins, serum IL-1 concentration, and myocardial collagen volume fraction (CVF%) increased in SHRs in the NOD1 agonist group, but the levels of NOD1 and Rip2, serum IL-1 concentration, and myocardial collagen volume fraction (CVF%) decreased in SHRs in the NOD1 inhibitor group. CONCLUSIONS NOD1/Rip2 expression increased during the progression of myocardial remodeling in SHRs. The NOD1 agonist increased NOD1 expression and promoted myocardial remodeling, while the NOD1 antagonist reduced NOD1/Rip2 expression and protected against myocardial remodeling.