| Systemic lupus erythematosus (SLE) and acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are common diesases in clinic. SLE is a chronic autoimmune disease characterized by multi-organ involvement and remarkable variability in clinical presentation. The pathogenesis of SLE might involve multiple factors, which cumulatively result in breakdown of self-tolerance and development of auto-immunity with end-organ damage. Severe infection, shock, trauma and burns and other non-cardiac diseases often lead to acute lung injury. Pulmonary capillary endothelial cells and alveolar epithelial cell were injuryed, diffuse pulmonary interstitial and alveolar edema were produced, which caused acute hypoxic respiratory insufficiency or failure.There is sonething in common between the above diseases. First of all, both are included in the context of autoimmune diseases. Immune disorders were happened in the pathological process of both diseases. Secondly, non-specific immune response plays an important role. Thirdly, massive inflammatory cytokines were released in both diseases.Radix Bupleuri (dried roots of Bupleurum chinense or Bupleurum scorzonerifolium), known as'Chai-Hu', is one of the most frequently prescribed crude herbs in the prescriptions of traditional Chinese medicine for the treatment of inflammatory diseases. Bupleurum smithii var. parvifolium is abundantly distributed in the northwest region of China and its roots are also used as Radix Bupleuri. Previous experiments in our lab confirmed that the crude polysaccharide (BPs) isolated from this plant (1) had a beneficial effect on systemic lupus erythematosus-like syndroma induced by CJ-S131 in BALB/c mice via inhibiting humoral immune hyperthyroidism, alleviating the index of spleen and ameliorating the glomerular injury, (2) alleviated ALI in rats that might relate with its inhibitory effect on over activation of complement and descent effect on complement deposits in lung tissues. Based on our previous studies and the role of macrophage in inflammatory diseases mentioned above, we studied the effect of BPs on macrophage functions for the purpose of finding out the possible target of BPs on inflammatory diseases; on the other hand, we investigated the effects of BPs on the inflammations in ALI rats in order to the learn its protective effects and specific mechanism.1. Effects of Bupleurum smithii on macrophage immunomodulatory activity in miceAIM To determine the immunomodulative effect of crude polysaccharides (BPs) isolated from the roots of Bupleurum smithii var. parvifolium on murine peritoneal macrophages.METHOD BALB/c mice were administered intragastrically with Bupleurum polysaccharides 20,40,80 mg·kg-1·d-1, or prednisone 3 mg·kg-1·d-1 or levamisole 25 mg·kg-1·d-1 from day 0 to day 6. The actived macrophages were induced by intraperitoneal injection of 1 mL 5% sodium thioglycollate and collected after sacrificed on day 7. The effect of BPs on the phagocytosis of chicken red blood cells (CRBC), antibody-mediated sheep red blood cells (IgG-SRBC) and self-apoptosis cells was measured, cytokines concentrations in the culture supernatants of both activated and imflamatory macrophages were determined by enzyme-linked immunosorbent assay and the secretion of nitric oxide (NO) was quantified by Griess reaction.Results For phagocytosis of apoptotic thymocytes, both the phagocytic rate and phagocytic index increased significantly in BPs 80 mg·kg-1·d-1 (P＜0.001, P＜0.01). A considerable enhancement of both rate and index of phagocytosis of IgG-SRBCs was observed in all three BPs groups as compared with control (P＜0.001). When it comes to phagocytosis of CRBCs, treatment with BPs and lavamisole increased the phagocytic rate and index significantly (P＜0.05).BPs 20,40 and 80 mg·kg-1·d-1 significantly decreased the NO and IL-6 secretion in activated macrophages (P＜0.001), but have no effect on TNF-a and IL-1βproduction. In macrophages treated with 1μg·ml-1 LPS, administration of 40 and 80 mg·kg-1·d-1 BPs suppressed NO concentration (P＜0.001), TNF-a (P＜0.01) and IL-1βproduction (P＜0.01). IL-6 level in the culture supernatants of inflammatory macrophages was inhibited by BPs treamtment.Conclusions Bupleurum polysaccharides up-regulated phagocytic activities but inhibited LPS-induced productions of proinflammatory mediators.2. Effects of Bupleurum smithii on acute lung injury in ratsAIM To determine the effect of crude polysaccharides (BPs) isolated from the roots of Bupleurum smithii var. parvifolium on ALI in rats.METHOD Wistar rats were randomly assigned into sham group, model group, BPs 2.5,5,10,20 mg·kg-1 group and Dexamethasone 2 mg·kg-1 group. A "two-hit" lung injury model characterized by hemorrhagic shock with resuscitation, followed by intratracheal LPS (lmg·kg-1) administration was established. H&E staining were used to determine the pathological changes and the effect of drugs. Wet-to-dry weight ratio was measured; neutrophils in the BALF were counted and MPO in the BALF was determined; protein concentration was tested by Coomassie brilliant blue method. ELISA was used to determine the levels of IL-6, TNF-a and IL-1βand total complement hemolytic activity in serum was measured.RESULTS Hemorrhagic shock with resuscitation, followed by intratracheal LPS (1mg·kg-1) administration has successfully induced the "two-hit" acute lung injury model. In Model group, serious injuries as assive bleeding, distorted and collapsed alveolars and thickening alveolar walls were found in pathological slices; wet-to-dry weight, numbers of neutrophils, levels of MPO, protein, TNF-a and IL-6 in BALF and the serum total complement hemolytic activity were all raised up significantly (P＜0.001). After oral administration, BPs significantly improved pathological injury. Inflammation were reduced, alveolar hemorrhage were extenuate, alveolar wall and inflammatory cell infiltration were decreased. BPs 10 and 20 mg·kg-1 significantly inhibited the ratio of wet-to-dry weight (P＜0.05). The level of protein and TNF-a (P＜0.01) were reduced by all dosages of BPs. BPs 5,10 and 20 mg·kg-1 inhibited the numbers of neutrophils, reduced the level of MPO and IL-6 in BALF (P＜0.01) significantly. BPs 20 mg·kg-1 significantly decreased the serum total complement hemolytic activity (P<0.05).CONCLUSIONS Our results demonstrated that hemorrhagic shock with resuscitation, followed by intratracheal LPS (lmg·kg-1) administration could induced the "two-hit" acute lung injury model successfully. BPs ameliorated ALI in rats as reducing epithelial and endothelial cell permeability, ameliorating alveolar and pulmonary interstitial edema and decreasing neutrophil infiltration. The sepecific mechanisms of BPs might relate with its inhibitory effect on secretion of proinflammatory factors (IL-6 and TNF-a) and on over activation of complement.
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