Salvianolic acid B protects from pulmonary microcirculation disturbance induced by lipopolysaccharide in rat

The aim of the present study was to examine the effect and possible mechanism of salvianolic acid B (SalB) on pulmonary microcirculation disturbance induced by lipopolysaccharide (LPS) in rat. Male Sprague-Dawley rats were subjected to thoracotomy under continuous anesthesia and mechanical ventilation. Albumin leakage from pulmonary capillary and the numbers of leukocytes adherent to the pulmonary capillary wall were determined for 60 min by an upright microscope upon LPS (2 mg · kg(-1) · h(-1)) infusion with or without administration of SalB (5 mg · kg(-1) · h(-1)). Pulmonary tissue wet-to-dry weight ratio, tumor necrosis factor α, and interleukin 8 in plasma and bronchoalveolar lavage fluid were measured. In addition, the expressions of E-selectin, intercellular adhesion molecule 1, and myeloperoxidase in pulmonary tissue were assessed by immunohistochemistry. The expressions of aquaporin 1 (AQP-1), AQP-5, metalloproteinase 2 (MMP-2), and MMP-9 were assessed by Western blot assay. Pretreatment with SalB significantly attenuated LPS-induced pulmonary microcirculatory disturbance, including the increase in leukocyte adhesion and albumin leakage. In addition, LPS increased pulmonary tissue wet-to-dry weight ratio and tumor necrosis factor α and interleukin 8 levels in plasma and bronchoalveolar lavage fluid enhanced the expression of E-selectin, intercellular adhesion molecule 1, myeloperoxidase, MMP-2, and MMP-9, whereas it decreased the expression of AQP-1 and AQP-5 in pulmonary tissue, all of which were attenuated by SalB pretreatment. Salvianolic acid B pretreatment improves pulmonary microcirculation disturbance and lung injury on LPS exposure. More studies are required to evaluate the potential of SalB as an option for protecting lung from endotoxemia.