Tianjin Medical Journal ›› 2023, Vol. 51 ›› Issue (10): 1090-1097.doi: 10.11958/20221976

• Experimental Research • Previous Articles     Next Articles

Effect and its mechanism of emodin on the ferroptosis of chondrocytes in rats with knee osteoarthritis

WANG Ke1(), YE Hanlu2,△()   

  1. 2. Department of Orthopedics and Traumatology
    2. Department of Endocrinology, Wuhan Hospital of Traditional Chinese Medicine, Wuhan 430014, China
  • Received:2022-12-02 Revised:2023-02-17 Published:2023-10-15 Online:2023-10-18
  • Contact: ∆E-mail:jueax516@163.com

Abstract:

Objective To investigate the effect and its mechanism of emodin on the ferroptosis of chondrocytes in rats with knee osteoarthritis (KOA). Methods A total of 96 SD rats were divided into the sham operation (sham) group, the KOA group, the emodin (EMO) group and the emodin+Nrf2 inhibitor (EMO+ML385) group, with 24 rats in each group. Except for the sham group, KOA rat models were established by modified Hulth method in each group. The tumor necrosis factor-α (TNF-α), nitric oxide (NO) and prostaglandin E2 (PGE2) levels were detected by enzyme-linked immunosorbent assay (ELISA). General morphology of knee joint was observed with naked eyes. The pathological morphology of knee joint cartilage was observed with safranine O-solid green staining. Apoptosis rate of chondrocytes of knee joint was detected by TdT-mediated dUTP nick end labeling (TUNEL) staining. Malondialdehyde (MDA), reactive oxygen species (ROS), glutathione (GSH) and ferrous ion (Fe2+) levels in knee joint cartilage were detected by biochemical reagent kit. Expression levels of matrix metalloproteinase (MMP)-3, MMP-13, collagen type II α1 (COL2A1), prostaglandin-endoperoxide synthase 2 (PTGS2), glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long chain family member 4 (ACSL4), nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) mRNA or protein in knee joint cartilage were detected by real-time fluorescence quantitative PCR (qRT-PCR), Western blot assay or immunohistochemistry. Results Compared with the sham group, the serum TNF-α, NO and PGE2 levels, Osteoarthritis Research Society International (OARSI) score, apoptosis rate, mRNA expression of MMP-3, MMP-13 and PTGS2, MDA, ROS, and Fe2+ levels, proportion of ACSL4 positive cells, and protein expression of ACSL4, nuclear Nrf2 and HO-1 increased in the KOA group. GSH levels, mRNA expression of COL2A1, proportion of GPX4 positive cells, and protein expression of GPX4 and cytoplasmic Nrf2 decreased (P<0.05). The articular cartilage was obviously damaged. EMO can improve the inflammatory reaction, knee joint cartilage tissue injury and chondrocyte ferroptosis of KOA rats, and further activate Nrf2/HO-1 signal pathway. ML385 not only inhibited the activation of Nrf2/HO-1 signal pathway, but also attenuated the improvement of EMO on knee joint cartilage tissue injury and chondrocyte ferroptosis of KOA rats. Conclusion Emodin can activate Nrf2/HO-1 signal pathway, inhibit chondrocyte ferroptosis and protect knee articular cartilage of KOA rats.

Key words: emodin, osteoarthritis, knee, arthritis, experimental, chondrocytes, ferroptosis, Nrf2/HO-1 signal pathway

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