Pravastatin attenuates sepsis-induced acute lung injury through decreasing pulmonary microvascular permeability via inhibition of Cav-1/eNOS pathway

Background: Disruption of alveolar endothelial barrier caused by inflammation drives the progression of septic acute lung injury (ALI). Pravastatin, an inhibitor of HMG Co-A reductase, has potent anti-inflammatory effects. In the present study, we aim to explore the beneficial role of pravastatin in sepsis-induced ALI and its related mechanisms.

Methods: A septic ALI model was established by cecal ligation and puncture (CLP) in mice. The pulmonary microvascular endothelial cells (PMVECs) were challenged with lipopolysaccharide (LPS). The pathological changes in lung tissues were examined by HE staining. The pulmonary microvascular permeability was determined by lung wet-to-dry (W/D) weight ratio and Evans blue staining. The total protein concentration in bronchoalveolar lavage fluid (BALF) was detected by BCA assay. The levels of TNF-α, IL-1β, and IL-6 were assessed by qRT-PCR and ELISA. Apoptosis was determined by flow cytometry and TUNEL. Western blotting was performed for detection of target protein levels. The expression of VE-Cadherin in lung tissues was evaluated by immunohistochemical staining.

Results: Pravastatin improved survival rate, attenuated lung pathological changes and reduced pulmonary microvascular permeability in septic mice. In addition, pravastatin restrained sepsis-induced inflammatory response and Apoptosis in the lung tissues and PMVECs. Moreover, pravastatin up-regulated the levels of junction proteins ZO-1, JAM-C, and VE-Cadherin. Finally, pravastatin suppressed inflammation, Apoptosis and enhanced the expression of junction proteins via regulating Cav-1/eNOS signaling pathway in LPS-exposed PMVECs.

Conclusion: Pravastatin ameliorates sepsis-induced ALI through improving alveolar endothelial barrier disruption via modulating Cav-1/eNOS pathway, which may be an effective candidate for treating septic ALI.