利用巨噬細胞株模式探討豆奶與發酵豆奶對發炎反應之影響

Abstract

本實驗以豆奶為基質，利用乳酸菌 (Streptococcus salivarius subsp. thermophilus CCRC 14085) 單獨或與雙叉桿菌 (Bificobacterium infantis CCRC 14633) 共同發酵，以 lipopolysaccharides (LPS) 誘導巨噬細胞 RAW 264.7之模式，探討豆奶及發酵豆奶甲醇萃取物對 nitric oxide (NO) 、 tumor necrosis factor (TNF)-α 、 interleukin (IL)-6 、 IL-1β 等發炎因子之影響，並進一步以Western blot分析巨噬細胞 inducible nitric oxide synthase (iNOS) 與 cyclooxygenase-2 (COX-2) 之蛋白質表現量。 結果顯示，豆奶及兩種發酵豆奶甲醇萃取物皆可有效抑制由 LPS 誘導所產生之 NO，且抑制能力隨著濃度增加而提升，其中又以豆奶甲醇萃取物之抑制能力最佳，其次為 S. thermophilus 發酵豆奶甲醇萃取物。iNOS酵素活性分析結果，推測此三種樣品均不改變 iNOS 酵素活性，而除豆奶甲醇萃取物之外， S. thermophilus 發酵豆奶與 S. thermophilus 及 B. infantis 共同發酵豆奶甲醇萃取物可明顯抑制經由 LPS 誘發產生之 iNOS 蛋白質表現量。另外，豆奶及兩種發酵豆奶甲醇萃取物不具抑制 COX-2 蛋白質表現之效用。於細胞激素試驗中發現，豆奶、 S. thermophilus 發酵豆奶與 S. thermophilus 及 B. infantis共同發酵豆奶甲醇萃取物均具有抑制 LPS 誘導 RAW 264.7巨噬細胞生成 TNF-α、 IL-6 及 IL-1β 之能力。

In the present study, the methanol extracts of soymilk and soymilk fermented with lactic acid bacteria (Streptococcus salivarius subsp. thermophilus CCRC 14085) alone or with bifidobacteria (Bificobacterium infantis CCRC 14633) simultaneously were evaluated for their effects on lipopolysaccharide (LPS)-induced nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β production by RAW 264.7 macrophages. In addition, the proteins expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) by macrophages as influenced by these methanol extracts were also investigated. Results revealed that the methanol extracts of soymilk and the prepared fermented soymilk dose-dependently suppress NO production of LPS-induced macrophages, with soymilk showed the highest inhibition ability followed by S. thermophilus-fermented soymilk. Extracts of soymilk and fermented soymilk were found not affected iNOS enzyme activity. Western blot analyses revealed that the methanol extracts of the fermented soymilk inhibited protein expression of iNOS in LPS-induced macrophages while it was not observed with soymilk. Moreover, these extracts did not show obvious inhibition on COX-2 protein expression in LPS-induced macrophages. On the other hand, the methanol extracts of soymilk and fermented soymilk all showed the inhibitory effect on LPS-induced TNF-α, IL-6 and IL-1β production by RAW 264.7 macrophages.