Activation of autophagy contributes to the protective effects of lycopene against oxidative stress-induced apoptosis in rat chondrocytes.

Oxidative stress is commonly associated with osteoarthritis (OA). Lycopene (LYC), a natural carotenoid compound, is an effective antioxidant with potential cartilage-protecting actions. However, how it affects hydrogen peroxide (H2 O2 )-induced damage to the cartilage is unclear. In this study, an in vitro oxidative stress model was developed via treating primary chondrocytes with H2 O2 . Western blot, immunohistochemistry, and quantitative RT-PCR (qRT-PCR) were used to assess the levels of related factors. Reactive oxygen species (ROS) and apoptosis levels were analyzed by the use of appropriate probes and flow cytometry. The expression and activity of stress-specific enzymes (malondialdehyde, superoxide dismutase, and catalase) were also assessed. The role of autophagy was explored by using the inhibitor, 3-methyladenine (3-MA), as well as monodansylcadaverine staining, western blotting, and red fluorescent protein-green fluorescent protein-light chain 3 lentivirus infection. The result showed LYC exerted significant chondrocyte-protective effects, including reduced inflammation and chondrocyte degradation, increased chondrocyte proliferation, apoptosis inhibition, and reduced ROS production. LYC could effectively induce autophagy in the H2 O2 treatment group, and this effect could be attenuated by 3-MA. In terms of mechanism, LYC played a role in inhibiting MAPK and PI3K/Akt/NF-κB axis, which down-regulates levels of mTOR and had a potential therapeutic significance for cartilage degeneration.

Collagen, agarose, alginate, and Matrigel hydrogels as cell substrates for culture of chondrocytes in vitro: A comparative study.

Autologous chondrocyte implantation (ACI) has emerged as a new approach to cartilage repair through the use of harvested chondrocytes. But the expansion of the chondrocytes from the donor tissue in vitro is restricted by limited cell numbers and dedifferentiation of chondrocytes. In this study, we used four types of hydrogels including agarose, alginate, Matrigel, and collagen type I hydrogels to serve as cell substrates and investigated the effect on proliferation and phenotype maintenance of chondrocytes. As a substrate for monolayer culture, collagen facilitated cell expansion and effectively suppressed the dedifferentiation of chondrocytes, as evidenced by fluorescein diacetate/propidium iodide (FDA/PI), hematoxylin-eosin staining (HE), Safranin O, immunofluorescenceassay, biochemistry analysis, and quantitative real-time polymerase chain reaction (qRT-PCR). Compared with that in agarose gels, alginate, and Matrigel, collagen accelerated cell proliferation and enhanced the expression of cartilage specific genes such as ACAN, SOX9, and COLII more markedly. Furthermore, significantly lower expression of COL I (an indicator of dedifferentiation) and COL X (the chondrocyte hypertrophy marker) was present in collagen group than in other groups. This indicated that collagen substrate can better support chondrocyte growth and maintain cell phenotype, due to that it might serve as a cartilage-like ECM to provide adhesive site for chondrocytes. In summary, collagen hydrogel is a promising cell substrate for chondrocytes culture for ACI.

A Novel Synthesized Sulfonamido-Based Gallate-JEZTC Blocks Cartilage Degradation on Rabbit Model of Osteoarthritis: An in Vitro and in Vivo Study.

BACKGROUND/AIMS: 3, 4, 5-trihydroxy-N-{4-[(5-methylisoxazol-3-yl) sulfamoyl] phenyl} benzamide (JEZTC), synthesized from gallic acid (GA) and sulfamethoxazole (SMZ), was reported with chondroprotective effects. However, the effects of JEZTC on osteoarthritis (OA) are still unclear. The goal of this study was to investigate the anti-osteoarthritic properties of JEZTC on interleukin-1-beta (IL-1ß) stimulated chondrocytes in vitro and a rabbit anterior cruciate ligament transaction (ACLT) OA model in vivo. METHODS: Changes in matrix metalloproteinases (MMPs) and apoptosis genes (bax, caspase 3 and tnf-α) and OA-specific protein (MMP-1) expression in vitro and in vivo were detected by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. The production of reactive oxygen species (ROS) were investigated upon the treatment of JEZTC in chondrocytes processed with IL-1ß in vitro and OA in vivo. Effect of JEZTC on OA was further studied by the macroscopic and histological evaluation and scores. The key proteins in signaling pathways inMAPK/P38, PI3KAkt and NF-κB also determined using western blot (WB) analysis. RESULTS: JEZTC could significantly suppress the expression of MMPs and intracellular ROS, while meaningfully increase the gene expression of tissue inhibitor of metalloproteinase-1 (TIMP-1). Moreover, there was less cartilage degradation in JEZTC group compared with the phosphate-buffered saline (PBS) group in vivo. Results also indicated that JEZTC exerts effect on OA by regulating MAPKs and PI3K/Akt signaling pathways to activate NF-κB pathway, leading to the down-regulation of MMPs. The chondro-protective effect of JEZTC may be related with its ability to inhibit chondrocyte apoptosis by reduction of ROS production. CONCLUSION: JEZTC may be a possible therapeutic agent in the treatment of OA.

Effect of a novel synthesized sulfonamido-based gallate-SZNTC on chondrocytes metabolism in vitro.

The ideal therapeutic agent for treatment of osteoarthritis (OA) should have not only potent anti-inflammatory effect but also favorable biological properties to restore cartilage function. Gallic acid (GA) and its derivatives are anti-inflammatory agents reported to have an effect on OA (Singh et al., 2003) [1]. However, GA has much weaker antioxidant effects and inferior bioactivity compared with its derivatives. We modified GA with the introduction of sulfonamide to synthesize a novel sulfonamido-based gallate named sodium salt of 3,4,5-trihydroxy-N-[4-(thiazol-2-ylsulfamoyl)-phenyl]-benzamide (SZNTC) and analyzed its chondro-protective and pharmacological effects. Comparison of SZNTC with GA and sulfathiazole sodium (ST-Na) was also performed. Results showed that SZNTC could effectively inhibit the Interleukin-1 (IL-1)-mediated induction of metalloproteinase-1 (MMP-1) and MMP-3 and could induce the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1), which demonstrated ability to reduce the progression of OA. SZNTC can also exert chondro-protective effects by promoting cell proliferation and maintaining the phenotype of articular chondrocytes, as evidenced by improved cell growth, enhanced synthesis of cartilage specific markers such as aggrecan, collagen II and Sox9. Expression of the collagen I gene was effectively down-regulated, revealing the inhibition of chondrocytes dedifferentiation by SZNTC. Hypertrophy that may lead to chondrocyte ossification was also undetectable in SZNTC groups. The recommended dose of SZNTC ranges from 3.91µg/ml to 15.64µg/ml, among which the most profound response was observed with 7.82µg/ml. In contrast, its source products of GA and ST-Na have a weak effect in the bioactivity of chondrocytes, which indicated the significance of this modification. This study revealed SZNTC as a promising novel agent in the treatment of chondral and osteochondral lesions.