[Mechanism of Tougu Xiaotong Capsules in delaying degeneration of osteoarthritis by regulating cholesterol metabolism in chondrocytes through lncRNA MALAT1].

From the perspective of lncRNA MALAT1 regulating cholesterol metabolism in chondrocytes, this paper explores the effect and mechanism of Tougu Xiaotong Capsules(TGXTC) in delaying the degeneration of osteoarthritis. After one week of adaptive feeding, 48(8-week-old) C57BL/6 mice were randomly divided into a blank group(12 mice) and a model group(36 mice) by random number table method. The mice in the model group were anesthetized by inhalation of 5% isoflurane, and the OA model was induced by Hulth method. The experiment randomly divided the mice into a model group(12 mice), a drug-positive group(taururso-deoxycholic acid)(12 mice), and a TGXTC group(12 mice). The drug-positive group was given 500 mg·kg~(-1) taurodeoxycholic acid by intragastric administration. TGXTC group was given TGXTC 368 mg·kg~(-1) by gavage. The blank group and model group were given the same amount of normal saline for four weeks. After the intervention, the mice in each group were killed under anesthesia, and the knee cartilage tissue was separated and collected. The morphologic changes of knee cartilage were observed. The level of lncRNA MALAT1 in the cartilage tissue was detected by real-time PCR. The protein expressions of ABCA1, ApoA1, LXRß, CHOP, and caspase-3 in mouse articular cartilage were detected by Western blot. Lentivirus-coated plasmid was used to transfect mouse chondrocytes with sh-MALAT1. The gene levels of lncRNA MALAT1 in mouse chondrocytes transfected with sh-MALAT1 were detected by real-time PCR. Western blot was used to detect the effect of TGXTC on the protein content of ABCA1, ApoA1, LXRß, CHOP, and caspase-3 in thapsigargin(TG)-induced mouse chondrocytes after lncRNA MALAT1 knockdown. Flow cytometry was used to detect the effect of TGXTC on apoptosis of TG-induced mouse chondrocytes after lncRNA MALAT1 knockdown. The results of HE and saffranine O staining showed that compared with the model group, the structure of the cartilage layer was basically intact; the damage degree of joint structure was significantly improved, and the cartilage matrix was significantly enhanced by saffranine O staining in the TGXTC group and drug-positive group. Compared with the model group, the lncRNA MALAT1 level was significantly decreased in the TGXTC group and drug-positive group. Compared with the model group, the protein content of ABCA1, ApoA1, and LXRß was significantly increased, while that of CHOP and caspase-3 in the TGXTC group and drug-positive group significantly decreased. Compared with the TG group, the lncRNA MALAT1 level in the TG+sh-MALAT1 group was decreased. The lncRNA MALAT1 level in the TG+sh-MA-LAT1+TGXTC group was increased compared with the TG+TGXTC group. Western blot results showed that compared with the model group, protein expressions of ABCA1, ApoA1, LXRß, CHOP, and caspase-3 in the TGXTC group were significantly decreased, after lncRNA MALAT1 knockdown, the regulation and apoptosis of ABCA1, ApoA1, LXRß, CHOP, and caspase-3 in TG-induced mouse chondrocytes were weakened by TGXTC. TGXTC can improve the disorder of cholesterol metabolism in OA chondrocytes and delay OA degeneration, which is closely related to the regulation of lncRNA MALAT1.

Achyranthes bidentata polysaccharides alleviate endoplasmic reticulum stress in osteoarthritis via lncRNA NEAT1/miR-377-3p pathway.

Endoplasmic reticulum stress (ERS) has been identified to be an important factor leading to chondrocyte apoptosis in osteoarthritis (OA). Previous studies have confirmed that Achyranthes bidentata polysaccharides (ABPS) can inhibit chondrocyte apoptosis; however, the mechanism of action of ABPS on chondrocyte ERS remains unclear. Thus in this study, we aim to investigate whether ABPS could inhibit OA-associated chondrocyte apoptosis by regulating ERS, especially by observing the relationship between the lncRNA NEAT1 and miR-377-3p, to explore further the protective mechanism of ABPS in OA. In vitro and in vivo experiments showed that ABPS inhibited chondrocyte ERS by regulating the expression of lncRNA NEAT1 and miR-377-3p. Moreover, both lncRNA NEAT1 silencing and miR-377-3p inhibition could attenuate the therapeutic effect of ABPS on ERS. Dual-luciferase results indicated that miR-377-3p targets the lncRNA NEAT1 gene in mouse chondrocytes. Therefore, we concluded that ABPS could inhibit thapsigargin (TG)-induced chondrocyte ERS through the lncRNA NEAT1/miR-377-3p axis.