探討益生菌應用於改善犬異位性皮膚炎症狀及菌相調節之影響

Abstract

犬異位性皮膚炎 (canine atopic dermatitis, CAD) 是一種慢性且具有頻繁搔癢行為的過敏性皮膚疾病。該疾病屬於第一型過敏過敏反應，主要受到第一型輔助T細胞 (type 1 T helper cells, Th1)/第二型輔助T細胞 (type 2 T helper cells, Th2) 反應失衡所影響，其在犬隻中為僅次於跳蚤感染的第二大過敏性皮膚炎，全世界犬隻的患病率約10–15%。以現階段的醫療技術還無法完全根治異位性皮膚炎，而反覆的抓撓行為及長期的回診會對犬隻及飼主的生活品質造成影響。近來，有許多文獻指出益生菌可藉由調節腸道菌相和改善腸道上皮結構，來影響整體的免疫平衡。本實驗室先前已利用AD小鼠模型證實Lactococcus cremoris subsp. cremoris APL002與Lacticaseibacillus paracasei subsp. paracasei APL008的混菌組合可能可以透過腸道免疫系統，使得脾臟中的Th1及Th2細胞比例下降，降低免疫球蛋白E (immunoglobulin E, IgE) 分泌，並改善小鼠的皮膚炎症狀，如表皮增生及皮膚損傷。 本研究旨在探討益生菌減緩CAD症狀之潛力。受試犬經獸醫師專業判斷後給予LCP (Lactococcus cremoris & Lacticaseibacillus paracasei) 益生菌膠囊持續服用60天，收集其試驗前、後之糞便、血液和皮膚拭子樣品，分析血液生化值與血漿中IgE含量，並使用16S全長核醣體基因分析 (full length 16S rRNA analysis) 分析皮膚及腸道微生物相組成。使用60天LCP膠囊後，AD犬的皮膚症狀獲得改善，且降低皮膚病灶評分 (canine atopic dermatitis extent and severity index, CADESI) 和搔癢視覺量表 (pruritus visual analogue scale, PVAS) 評分。此外，經益生菌處理的AD犬，除了顯著降低其血漿中IgE濃度外 (P < 0.05)，同時也調節Th1/Th2相關細胞激素的分泌。在微生物分析中，發現在服用LCP益生菌膠囊後對皮膚和腸道菌相的組成也產生影響，如：Shigella flexneri (皮膚) 和Romboutsia (腸道)。另外，在分析糞便中的短鏈脂肪酸後，也發現LCP可以提升犬隻腸道中的乙酸、丙酸及丁酸的含量。綜上所述，Lc. cremoris subsp. cremoris APL002和L. paracasei subsp. paracasei APL008具有改善犬異位性皮膚炎之潛力，期望未來有助於減緩犬異位性皮膚炎。

Canine atopic dermatitis (CAD) is a common chronic inflammatory and pruritic allergic skin disease. This disease belongs to type 1 hypersensitivity and predominantly results from the heightened type 2 T helper cell (Th2) inflammatory response over type 1 T helper cell (Th1) response. The prevalence of dogs is approximately 10–15%. There is no effective treatment for CAD, that affects the life quality of the AD-afflicted dogs and their owners. Some studies have indicated a correlation between the good condition of the skin and a healthy gastrointestinal system. The resident gut microbiota plays a crucial role in functional integrity of the intestinal barrier, maintenance of structure and regulation of the immune system. In a previous study, our lab selected Lactococcus cremoris subsp. cremoris APL002 and Lacticaseibacillus paracasei subsp. paracasei APL008 from Mongolian fermented milk. We found that the probiotic mixture could improve AD-like features and reduce specific immunoglobulin E (IgE) in AD mice model. Thus, the aim of this study was to investigate the effect of probiotics to alleviate the symptoms of CAD. In the present study, an open-label single-arm clinical study was conducted with AD dogs for 60 days at animal hospital. Each dog collected stool, skin swab, and venous blood specimens at three-time points, i.e., before, and after LCP (Lactococcus cremoris & Lacticaseibacillus paracasei) capsules administration for 30 and 60 days (one capsule per day). The skin and fecal microbiome were further analyzed by the full length 16S rRNA analysis. After 60 days, the skin lesion and the level of scratching were improved after LCP intervention accompany with lower canine atopic dermatitis extent and severity index (CADESI) and pruritus visual analogue scale (PVAS) scores. Moreover, administration of probiotics could significantly decline the level of IgE (P < 0.05) and regulate the secretions of Th1/Th2-related cytokines. Further microbiota analysis indicated that LCP intervention could modulate the composition of microbiota in the skin and gut, including Shigella flexneri (skin) and Romboutsia (gut). In short-chain fatty acid analysis, the levels of acetic acid, propionic acid, and butyric acid were increased after intaking LCP capsules for 60 days. In summary, the administration of LCP probiotic capsules could alleviate CAD symptoms by regulating the immune response via modifying the composition of gut and skin microbiota. Through our findings, the mixture of Lc. cremoris subsp. cremoris APL002 and L. paracasei subsp. paracasei APL008 might become a potential strategy for alleviating CAD in the future.