Pachymic Acid Prevents Hemorrhagic Shock-Induced Cardiac Injury by Suppressing M1 Macrophage Polarization and NF-B Signaling Pathway

Hemorrhagic shock (HS) is the leading cause of death in trauma patients. Inflammation following HS can lead to cardiac damage. Pachymic acid (PA), a triterpenoid extracted from Poria cocos, has been found to possess various biological activities, including anti-inflammatory and anti-apoptotic properties. Our research aims to investigate the protective effects of PA against HS-induced heart damage and the underlying mechanisms involved. Male Sprague-Dawley rats were intraperitoneally injected with PA (7.5 or 15mg/kg) daily for three days. Subsequently, we created a rat model of HS by drawing blood through a catheter inserted into the femoral artery followed by resuscitation. The results revealed that HS led to abnormalities in hemodynamics, serum cardiac enzyme levels, and cardiac structure, as well as induced cardiac apoptosis. However, pretreatment with PA effectively alleviated these effects. PA-pretreatment also suppressed mRNA and protein levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor alpha (TNF-alpha) in the heart tissues of HS rats. Additionally, PA-pretreatment reduced inflammatory cell infiltration and M1 macrophage polarization while exaggerating M2 polarization in HS rat hearts. The study observed a decreased proportion of the expression of of M1 macrophages (CD86+) and their marker (iNOS), along with an increased proportion of the expression of M2 macrophages (CD206+) and their marker (Arg-1). Notably, PA-pretreatment suppressed NF-kappa B pathway activation via inhibiting NF-kappa B p65 phosphorylation and its nuclear translocation. In conclusion, PA-pretreatment ameliorates HS-induced cardiac injury, potentially through its inhibition of the NF-kappa B pathway. Therefore, PA treatment holds promise as a strategy for mitigating cardiac damage in HS.