Comparison of the effects of oxidative and inflammatory stresses on rat chondrocyte senescence

Abstract

Osteoarthritis (OA) is an age-related degenerative joint disease that causes progressive cartilage loss. Chondrocyte senescence is a fundamental mechanism that contributes to the imbalance of matrix homeostasis in OA by inducing senescence-associated secretory phenotype (SASP). Although OA chondrocytes are mainly exposed to oxidative and inflammatory stresses, the role of these individual stresses in chondrocyte senescence remains unclear. In this study, we compared the effects of these stresses on the senescence of rat chondrocytes. Rat chondrocytes were treated with H2O2 and a combination of IL-1β and TNF-α (IL/TNF) to compare their in vitro effect on senescent phenotypes. For in vivo evaluation, H2O2 and IL/TNF were injected into rat knee joints for 4 weeks. The in vitro results showed that H2O2 treatment increased reactive oxygen species, γ-H2AX, and p21 levels, stopped cell proliferation, and decreased glycosaminoglycan (GAG)-producing ability. In contrast, IL/TNF increased the expression of p16 and SASP factors, resulting in increased GAG degradation. Intraarticular injections of H2O2 did not cause any changes in senescent markers; however, IL/TNF injections reduced safranin O staining and increased the proportion of p16- and SASP factor-positive chondrocytes. Our results indicate that oxidative and inflammatory stresses have significantly different effects on the senescence of rat chondrocytes.

Upregulated FOXM1 stimulates chondrocyte senescence in Acot12-/-Nudt7-/- double knockout mice

“…Recently, molecular mechanisms underlying the contribution of cell senescence to the initiation and progression of OA have been reported. Oxidative stress may play a major role in the association between chondrocyte senescence and OA development [34][35][36]. Increased levels of intracellular ROS in the cartilage contribute to aging changes in cells and tissues by causing oxidative damage to proteins, lipids, and DNA, resulting in chondrocyte senescence, apoptosis, and cartilage matrix loss.…”

siRNA therapy in osteoarthritis: targeting cellular pathways for advanced treatment approaches

“…The aggregation of senescent chondrocytes promotes the progression of OA by disrupting the ECM homeostasis (27). The senescence-associated secretory phenotype (SASP) expressed by senescent chondrocytes is one of the key contributors to ECM impairment, causing an imbalance between ECM synthesis and degradation through the secretion of various cytokines and proteases such as interleukin 6 (IL-6), matrix metalloproteinases 13 (MMP13), and a disintegrin and metalloprotease with thrombospondin motifs 5 (ADAMTS5) (28). Research targeting cellular senescence provides insights for siRNA therapy.…”