title: Tougu Xiaotong capsule inhibits the tidemark replication and cartilage degradation of papain-induced osteoarthritis by the regulation of chondrocyte autophagy.
abstract: The tidemark is located between calciﬁed and non-calciﬁed cartilage matrices. Tidemark replication plays an important role in the pathogenesis of osteoarthrosis (OA). Autophagy, or cellular self-digestion, is an essential cellular homeostasis mechanism that was found to be deficient in osteoarthritic cartilage. This study evaluated the effects of Tougu Xiaotong capsule (TXC) on the tidemark replication and cartilage degradation, and also investigated LC3 I/II, which executes autophagy, the potential role of ULK1, an inducer of autophagy, and Beclin1, a regulator of autophagy, in the development of a papain-induced OA in rat knee joints. Using a papain-injected knee rat model, standard histological methods were used to validate our model as well as treatment with TXC or glucosamine (GlcN). After 12 weeks of treatment, the changes of cartilage structure were observed by digital radiography (DR), optical microscopy, scanning electron microscopy and transmission electron microscopy, and the LC3 I/II, ULK1 and Beclin1 levels were measured by western blotting. Cartilage degradation was evaluated by the Mankin score on parafﬁn-embedded sections stained with Safranin O-fast green. TXC was found to improve the arrangement of subchondral bone collagen fibers and calcium phosphate crystals, inhibit the tidemark replication and delay the cartilage degradation in the papain-induced OA. Our results also showed that LC3 I/II, ULK1 and Beclin1 levels in both the TXC+OA and GlcN+OA groups were significantly increased compared to those in the OA group. The results indicate that TXC could inhibit the tidemark replication and cartilage degradation by the regulation of chondrocyte autophagy.
authors.affiliation: Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, People's Republic of China.
authors.forename: Xihai
authors.initials: X
authors.lastname: Li
authors.forename: Wenna
authors.initials: W
authors.lastname: Lang
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Ye
authors.forename: Fangrong
authors.initials: F
authors.lastname: Yu
authors.forename: Huiting
authors.initials: H
authors.lastname: Li
authors.forename: Jiashou
authors.initials: J
authors.lastname: Chen
authors.forename: Liangliang
authors.initials: L
authors.lastname: Cai
authors.forename: Wenlie
authors.initials: W
authors.lastname: Chen
authors.forename: Ruhui
authors.initials: R
authors.lastname: Lin
authors.forename: Yunmei
authors.initials: Y
authors.lastname: Huang
authors.forename: Xianxiang
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D001842:Bone and Bones / Q000473:pathology; D002356:Cartilage / Q000187:drug effects* / Q000473:pathology*; D019902:Chondrocytes / Q000187:drug effects* / Q000473:pathology*; D004195:Disease Models, Animal; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D008297:Male; D020370:Osteoarthritis, Knee / Q000139:chemically induced / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology*; D010206:Papain / Q000009:adverse effects; D011859:Radiography; D051381:Rats
chemical_list: D004365:Drugs, Chinese Herbal; C528129:tougu xiaotong; D010206:Papain