臺灣水鹿鹿茸於金黃色葡萄球菌感染及卵白蛋白致敏小鼠模式之免疫調節影響

Abstract

鹿茸乃鹿科動物未完全骨化而密生絨毛的角。其於傳統東方藥學中被視為極其珍貴的健康食品或藥材，具有強健體魄、提升免疫力之功效。然而，目前仍舊缺乏科學性證據足以證明鹿茸之免疫調節機能性，且其調節機制亦屬未知。是故，本研究即針對臺灣水鹿鹿茸及其萃取物之抗感染及抗過敏機能性進行探討。 於體外細胞試驗中，將鹿茸沸水萃取物及冷水萃取物分別與RAW 264.7小鼠巨噬細胞株、小鼠初代脾臟細胞及小鼠腹腔細胞共同培養後，再分別針對特定細胞進行細胞增生、細胞吞噬活性及細胞激素分泌試驗。另以金黃色葡萄球菌感染小鼠模式，評估預口服鹿茸萃取物及鹿茸粉之抗感染效果。細胞試驗的結果顯示，兩種鹿茸萃取物均可刺激脾臟細胞以及RAW 264.7細胞株之細胞增生，且其增生比隨萃取物添加劑量增加而上升。此外，鹿茸萃取物亦可刺激RAW 264.7細胞株吞噬金黃色葡萄球菌之吞噬活性。於巨噬細胞之抗發炎試驗則顯示，鹿茸萃取物可顯著抑制經脂胞壁酸刺激而大量釋出之前發炎細胞激素（TNF-α, IL-6, IL-12 p40）。細胞試驗的結果證實了鹿茸萃取物之多效性，而可同時具有刺激免疫反應（促進細胞增生、細胞吞噬活性）及抑制免疫反應（抗發炎反應）的效果。 金黃色葡萄球菌感染小鼠試驗顯示，腎臟及腹腔沖洗液之感染菌數以未服食鹿茸沸水萃取物及鹿茸粉者顯著較高。此外，口服給予鹿茸沸水萃取物及鹿茸粉劑量高於5 mg/20g體重者，其血清中前發炎細胞激素IL-6及TGF-β1，則顯著較正控制組為低。 本研究進一步以卵白蛋白致敏小鼠評估口服鹿茸粉之過敏免疫調節效果。口服鹿茸粉劑量高於5 mg/20g體重之小鼠，其血清免疫球蛋白E及卵白蛋白特異性免疫球蛋白E之濃度顯著較正控制組為低。此外，分離自口服鹿茸粉之小鼠脾臟細胞，其分泌第一型輔助T細胞細胞激素（TNF-α, IL-2, IFN-γ）及輔助T細胞17細胞激素（IL-17A, IL-17F, IL-21）之能力俱顯著提升。 綜上所述，本研究分別於體內及體外試驗，證實了鹿茸樣品對於金黃色葡萄球菌感染小鼠及卵白蛋白致敏小鼠具有抗感染以及抗過敏之預防效果。其保護機制推測來自於鹿茸樣品可提升第一型輔助T細胞反應，同時具有調節發炎反應之效果。

Velvet antler (VA) is the unossified antler of Family Cervidae. It is traditionally used as a valuable medicine or healthy food supplement to enhance vital energy and immune system in oriental ethno-pharmacology. However, there is still lack of scientific evidence on the immunomodulatory activities of VA. The underlying mechanisms are also fairly unknown. Thus, the purpose of this study was to evaluate the effects of VA of Formosan sambar deer (Cervus unicolor swinhoei) and its extracts on the anti-infective and anti-allergic activities. For in vitro study, VA water-boiled-extract (VA boiled) and VA cold-water-soaked-extract (VA soaked) were co-incubated with RAW 264.7 macrophage cells, mouse primary splenocytes or mouse peritoneal cells, respectively. Cytokine production, cell proliferation activities and phagocytic activities were further measured. Additionally, the in vivo anti-infective effects of VA extracts and VA powder were assayed by Staphylococcus aureus-infected mouse model. In vitro data indicated that both VA extracts stimulated the proliferation of resting splenocytes and RAW 264.7 macrophages in a dose-dependent manner up to the highest concentration used (150 μg/ mL). The highly enhanced S. aureus-phagocytic activity of RAW 264.7 macrophage was also verified after treatment with the VA extracts. Moreover, the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-12 p40) induced by lipoteichoic acid was significantly suppressed (P < 0.05) after co-cultured with both VA extracts in a dose-dependent manner. In vitro tests indicated that the VA extracts showed pleiotropic effects with both immuno-stimulative and immunosuppressive activities in this study. Animal tests in S. aureus-infected mice demonstrated that the numbers of infected bacteria determined in the kidneys and peritoneal lavage fluid of S. aureus-infected mice were significantly higher (P < 0.05) than those found in the same organs of mice orally administered with the VA boiled or VA powder. Moreover, the mice that were pretreated with VA boiled and 5 mg/20g body weight or higher dosage of VA powder produced significantly lower levels (P < 0.05) of pro-inflammatory cytokines, IL-6 and TGF-β1 than the positive control group. Furthermore, the in vivo anti-allergic activity of the VA powder was performed by ovalbumin (OVA)-sensitized mouse model. The concentrations of total IgE and OVA-specific IgE in sera of OVA-sensitized mice were significantly lower (P < 0.05) after administrated VA powder for 4 weeks. Besides, the ex vivo results indicated that the secretion of Th1 (TNF-α, IL-2, IFN-γ) and Th17 (IL-17A, IL-17F, IL-21) cytokines by splenocytes were significantly increased (P < 0.05) in the VA powder-administered mice groups. In conclusion, this study demonstrated the protective effects induced by the VA samples in S. aureus-infected and OVA-sensitized mouse models. The protective mechanisms of the VA samples might include a Th1 responses immune enhancer and a pro-inflammatory cytokine modulator.