Anisodamine hydrobromide protects against acute lung injury in septic rats induced by lipopolysaccharide or cecal ligation and puncture via inhibiting apoptosis and pyroptosis

Abstract

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. The lung failure for sepsis is reported in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused Coronavirus Disease 2019 (COVID-19), and patients in the intensive care unit (ICU). We previously reported that anisodamine hydrobromide (Ani HBr), an extract from the Chinese herb Anisodus tanguticus (Maxim) Pascher, could alleviate acute kidney injury in septic rats. In this study, we test whether Ani HBr protects against lung injury in septic rats. Adult specific pathogen-free (SPF) male Sprague-Dawley (SD) rats were intraperitoneally injected with 5 mg/kg lipopolysaccharide (LPS) for 4 h or underwent cecal ligation and puncture (CLP) surgery for 24 h, followed by another 24 h treatment of Ani HBr (0, 1.8 and 5.4 mg/kg) or atropine (5 mg/kg) via tail intravenous injection. Lung injury was evaluated by hematoxylin and eosin (H&E) staining, serum levels of creatine kinase (CK), lactic acid (LA), lactic dehydrogenase (LDH), CXCL8 and tumor necrosis factor (TNF-α), serum and lung tissue levels of superoxide dismutase (SOD) and malonaldehyde (MDA), immunohistochemistry (IHC) staining of GSDMD and NLRP3, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The protective mechanisms of Ani HBr against apoptosis and pyroptosis in lung tissues were examined by detecting the IL-1β, (pro) caspase-1, GSDMD and NLRP3 for pyroptosis, and (pro)caspase-3, Bcl-2 and Bax for apoptosis by Western Blot, respectively. Results showed that Ani HBr alleviated histopathologic injuries of the lung including inflammatory cell infiltration, and alveolar damages and edema in LPS- and CLP-induced septic rats. Ani HBr suppressed LPS- and CLP-induced CK, LA, LDH, CXCL8 and TNF-α in serum. Ani HBr reduced MDA in serum and lung tissue in septic rats, while elevated SOD activity. Ani HBr inhibited the positive cell rate of GSDMD and NLRP3 in lung sections induced by LPS and CLP, and inhibited the GSDMD and NLRP3 expression induced by LPS and CLP. Ani HBr inhibited LPS- and CLP-induced apoptosis in lung tissues. In accordance with the IHC staining results, Ani HBr inhibited expressions of IL-1β, NLRP 3, caspase-1 and GSDMD. The proapoptotic markers including Bax and (pro) caspase 3 were reduced by Ani HBr, and antiapoptotic marker Bcl-2 was increased by Ani HBr. The protective effects of Ani HBr at 5.4 mg/kg were better than 1.8 mg/kg and atropine. Therefore, Ani HBr alleviates acute lung injury in septic rats, which provides evidence supporting the clinical therapy of lung injury by Ani HBr.