The regulatory role and mechanism of lncTUG1 on cartilage apoptosis and inflammation in osteoarthritis.

BACKGROUND: Long-stranded non-coding RNA TUG1 is lowly expressed in osteoarthritic chondrocytes. This study aimed to elucidate the role of TUG1 in osteoarthritic cartilage damage and the underlying mechanisms. METHODS: Combined database analysis, using primary chondrocytes as well as the C28/I2 cell line, was performed by qRT-PCR, Western blotting, and immunofluorescence to determine the expression of TUG1, miR-144-3p, DUSP1, and other target proteins. Dual luciferase reporter gene and RIP to verify direct interaction of TUG1 with miR-144-3-p and miR-144-3-p with DUSP1, Annexin V-FITC/PI double staining to detect apoptosis. CCK-8 to detect cell proliferation. The biological significance of TUG1, miR-144-3p, and DUSP1 was assessed in vitro experiments using siRNA for TUG1, mimic and repressor for miR-144-3p, and overexpression plasmid for DUSP1. In this study, all data were subjected to a t-test or one-way analysis of variance with a p-value < 0.05 as the cutoff. RESULTS: TUG1 expression was closely associated with osteoarthritic chondrocyte damage, and knockdown of TUG1 significantly promoted chondrocyte apoptosis and inflammation. In the present study, we found that TUG1 inhibited chondrocyte apoptosis and inflammation by competitively binding miR-144-3p, deregulating the negative regulatory effect of miR-144-3p on DUSP1, promoting DUSP1 expression, and inhibiting the p38 MAPK signaling pathway. CONCLUSIONS: In conclusion, our study clarifies the role of the ceRNA regulatory network of TUG1/miR-144-3p/DUSP1/P38 MAPK in OA cartilage injury and provides an experimental and theoretical basis for genetic engineering tools to promote articular cartilage repair.

CTHRC1 mediates IL­1ß­induced apoptosis in chondrocytes via JNK1/2 signaling.

Osteoarthritis (OA), also known as degenerative joint disease or degenerative arthritis, is characterized by chondrocyte apoptosis. The aim of the present study was to investigate the effects of collagen triple helix repeat containing 1 (CTHRC1) and the c­Jun N­terminal kinase (JNK) 1/2 inhibitor SP600125 on rat chondrocytes cultured in vitro with interleukin (IL)­1ß. Chondrocytes were treated with different doses of IL­1ß and cell viability and CTHRC1 expression were assessed using Cell Counting Kit­8 and western blot assays, respectively. In separate experiments, chondrocytes were treated with CTHRC1­expressing constructs (pLVX­Puro­CTHRC1) and/or SP600125, or IL­1ß with either CTHRC1 short hairpin (sh)RNA constructs (shNRA­CTHRC1) or SP600125. The expression of CTHRC1, B­cell lymphoma (Bcl)­2, Bcl­2­associated X protein (Bax), cleaved caspase­3, poly ADP ribose polymerase (PARP)­1 and matrix metalloproteinase (MMP)­13 was measured using reverse transcription­quantitative polymerase chain reaction and western blotting assays. A Cell Counting Kit­8 assay was performed to examine cell viability. Annexin V/propidium iodide staining and flow cytometry assays were used to detect chondrocyte apoptosis. The expression of JNK1/2 and phosphorylated JNK1/2 was measured using western blotting. CTHRC1 was highly expressed in patients with OA compared with normal controls. IL­1ß treatment (5, 10 and 20 ng/ml) increased the protein expression of CTHRC1 in a dose­dependent manner and decreased the viability of chondrocytes in a time­dependent manner. pLVX­Puro­CTHRC1 mimics the effect of IL­1ß on chondrocyte apoptosis and JNK1/2 activity, and this is reversed by SP600125 treatment. However, transfection with shRNA­CTHRC1 or treatment with SP600125 inhibited IL­1ß­induced cell apoptosis and JNK1/2 activation. These results indicate that CTHRC1 downregulation may protect chondrocytes from IL­1ß­induced apoptosis by inactivating the JNK1/2 pathway.

Effects of five treatment regimens on blood loss and blood transfusion in total knee arthroplasty: a preliminary study in China
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OBJECTIVE: Our study is aimed to explore effects of five treatment regimens on blood loss and blood transfusion rate in total knee arthroplasty (TKA) patients. METHODS: 191 TKA patients were divided into the rivaroxaban, nadroparin, and tranexamic acid groups (n = 37 each) as well as into the affected-limb-position and tourniquet group (n = 40 each). A 3-month follow-up after operation was needed for all patients. The total blood loss, hidden blood loss, and dominant blood loss were recorded, and hemoglobin and red blood cell changes, pain and knee swelling degrees, hospital for special surgery (HSS), and American knee society (KSS) knee scores were observed. RESULTS: When compared with the rivaroxaban, nadroparin, and tourniquet groups, TKA patients' dominant blood loss, hidden blood loss, total blood loss, rate and volume of blood transfusion in the tranexamic acid and affected-limb-position groups were significantly decreased. While 7 days after operation, the hemoglobin and red blood cells in the tranexamic acid and affected-limb-position groups were significantly increased. At 1 month and 3 months after operation, when compared with the rivaroxaban, nadroparin, and tourniquet groups, the HSS and KSS scores in the tranexamic acid and affected-limb-position groups were all increased. In comparison with the rivaroxaban, nadroparin, and tourniquet groups, the D-Dimers after operation in the tranexamic acid and affected-limb-position groups were significantly lower. CONCLUSION: These results demonstrated that for TKA patients, the tranexamic acid and affected-limb-position could obviously reduce the blood loss and blood transfusion rate.
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Inhibition of the p38-MAPK signaling pathway suppresses the apoptosis and expression of proinflammatory cytokines in human osteoarthritis chondrocytes.

This study aims to investigate the effects of p38-MAPK signaling pathway on the apoptosis and expression of proinflammatory cytokines in human osteoarthritis (OA) chondrocytes. Human articular cartilage specimens were obtained from 57 OA patients and 31 patients with lower extremity traumatic amputations. The expressions of p38-MAPK pathway-related proteins in cartilage tissue were detected by immunochemistry. Cultured chondrocytes isolated from human OA cartilage were assigned into the blank group, the IL-1ß group, the PD (PD980959, ERK pathway inhibitors)+IL-1ß group, the SB (SB203580, p38 pathway inhibitors)+IL-1ß group, and the SP (SP600125, JNK signaling pathway inhibitors)+IL-1ß group. Cell proliferation and apoptosis were detected by MTT assay and flow cytometry. Western blotting was used to detect the expressions of MAPK pathway-related proteins. The mRNA expressions of IL-1, IL-6, and TNF-α were detected by qRT-PCR. The positive rates of p-p38, p-JNK and p-ERK in OA cartilage were higher than those in normal cartilage. Compared with the blank group, cell proliferation rate was decreased, cell apoptotic rate was increased, the mRNA expressions of IL-1, IL-6, TNF-α and the expressions of p-p38, p-JNK and p-ERK were increased in the IL-1ß group, while opposite trends were observed in the PD+IL-1ß, SB+IL-1ß, and SP+IL-1ß groups. Our study provides evidence that inhibition of the p38-MAPK signaling pathway could suppress the apoptosis and expression of proinflammatory cytokines in human OA chondrocytes.