Dilong Attenuates Pathological Cardiac Hypertrophy Through Akt/mTOR and NF-κB Signaling in Pressure Overload-induced Rats

Background: Dilong (earthworm), a traditional Chinese medicine obtained from the dried body of Pheretima aspergillum (E. Perrier), has proven cardioprotective effects in cardiovascular disorders. We aimed to investigate the potential therapeutic application of Dilong in preventing cardiomyocyte fibrosis and inflammation during cardiac hypertrophy (CH) after pressure overload (PO). Methods: We used the active protein compounds of Dilong (DAPC) to treat CH in vivo and in vitro . Hypertrophic rats were generated by abdominal aortic constriction (AAC)-surgery in male Wistar rats. DAPC (low-dose, 400 mg/kg per day; high-dose, 800 mg/kg per day, intraperitoneal injection [i.p.]) or captopril (50 mg/kg per day, i.p.) were given to rats for 3 weeks post AAC-surgery. Primary neonatal rat ventricular myocytes (NRVMs) isolated from 1-to 2-day-old SD rats were CH induced by phenylephrine (PE, 50 μ M) with or without DAPC (low-dose, 4 mg/mL; high-dose, 8 mg/mL) or captopril (10 μ M). Myocardial hypertrophy was identified by the heart weight index. Left ventricle remodeling and fibrosis of hypertrophic rats were evaluated by hematoxylin and eosin (H&E) staining, Mason staining, and Wheat germ agglutinin (WGA) staining. Using quantitative real-time PCR to examine the expressions of hypertrophic markers and inflammatory cytokines at mRNA levels. Additionally, protein expression of the Akt/mTOR and NF-κB signaling pathways were evaluated by western blot assay. Results: DAPC markedly decreased heart weight index and improved pathological morphology of the myocardium in AAC-induced rats. Of note, DAPC inhibits hypertrophic biomarkers ANP and BNP in vivo and in vitro . Meanwhile, the levels of IL-1β, IL-6, and TNF-α were decreased. Interestingly, DAPC inhibited the activation of Akt/mTOR and NF-κB proteins, which were in line with the in vitro findings. Conclusion: DAPC treatment in rats with PO-induced CH prevented cardiac fibrosis and had anti-inflammatory effects via regulation of the Akt/mTOR and NF-κB pathways.