Beneficial effects of Houttuynia cordata polysaccharides on “two-hit” acute lung injury and endotoxic fever in rats associated with anti-complementary activities

Lu, Yan; Jiang, Yun; Ling, Lijun; Zhang, Yunyi; Li, Hong; Chen, Daofeng

Histological examination revealed marked inflammation, extensive alveolar wall thickness, congestion as well as diffused interstitial infiltration in ALI. The immunohistochemistry showed over-activation of complement in ALI by the abundantly increased complement activation products deposition. The administration of CHCP (especially 50 and 100 mg/kg) significantly improved the histologic changes combined with the inhibition of the overactivation of complement system, the regulation of the oxidantantioxidant imbalance, as well as reducing the numbers of leukocytes and neutrophils in BALF. The protective effect of CHCP against ALI was also accompanied with a decrease in pulmonary edema indicated by lung W/D weight ratio, and a reduction in protein concentrations in the BALF, which represented a preserved pulmonary epithelial-endothelial barrier function 11 . Activation of the complement system decreases complement levels in serum, which can be accounted for by the reduction in C3 or C4 concentrations 33 . In the Sham group, minor surgical injuries caused a slight activation of the complement cascade, represented by the minimal decrease of hemolysis of serum. The "two-hit" ALI caused significantly more complement consumption. Oral administration of CHCP (100 and 50 mg/kg) apparently reduced the consumption of complement system. The effects of CHCP on C3 and C4 were consistent with the results of the in vitro complement-target test.