UC-II全名是未變性二型膠原蛋白,它的作用機轉跟葡萄糖胺、軟骨素完全不同——後兩者是嘗試提供軟骨組成的原料,UC-II則是透過「口服耐受性」機制,讓腸道免疫系統降低對關節軟骨中第二型膠原蛋白的攻擊反應,屬於免疫調節路徑,而不是單純的原料補充[1]。2007年一篇發表於《Toxicology Mechanisms and Methods》的犬隻臨床試驗,將關節炎狗狗分成安慰劑、UC-II、葡萄糖胺加軟骨素、以及三者合併四組,結果發現UC-II組在疼痛與跛行改善上的表現優於單獨使用葡萄糖胺加軟骨素[1]。後續也有研究將UC-II與處方消炎藥物直接比較,發現在改善行動能力方面具有非劣性的表現[2],2022年一篇針對退化性關節疾病犬隻的長期追蹤研究,也進一步支持UC-II作為長期日常保健成分的定位[5],顯示這不只是十幾年前的單一發現,而是持續累積中的研究方向。
D'Altilio M, Peal A, Alvey M, et al. Therapeutic efficacy and safety of undenatured type II collagen singly or in combination with glucosamine and chondroitin in arthritic dogs. Toxicology Mechanisms and Methods. 2007. PubMed. https://pubmed.ncbi.nlm.nih.gov/20020968/
Evaluation of the Effects of Undenatured Type II Collagen (UC-II) as Compared to Robenacoxib on the Mobility Impairment Induced by Osteoarthritis in Dogs. PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6789547/
Barbeau-Grégoire M, Otis C, Cournoyer A, et al. A 2022 Systematic Review and Meta-Analysis of Enriched Therapeutic Diets and Nutraceuticals in Canine and Feline Osteoarthritis. International Journal of Molecular Sciences. 2022. PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9499673/
Merck Veterinary Manual. Osteoarthritis in Dogs and Cats. https://www.merckvetmanual.com/musculoskeletal-system/osteoarthritis-in-dogs-and-cats/osteoarthritis-in-dogs-and-cats
Cabezas MÁ, Benito J, Ortega Á, Garcia-Pedraza E. Long-term supplementation with an undenatured type-II collagen (UC-II) formulation in dogs with degenerative joint disease: Exploratory study. Open Veterinary Journal. 2022. PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8956235/