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  • Do antioxidants inhibit oxidative-stress-induced autophagy of tenofibroblasts?

Do antioxidants inhibit oxidative-stress-induced autophagy of tenofibroblasts?

Journal of orthopaedic research : official publication of the Orthopaedic Research Society (2014-03-20)
Ra-Jeong Kim, Young-Sool Hah, Chang-Meen Sung, Jae-Ran Kang, Hyung Bin Park
ABSTRACT

Recent research on tendinopathy has focused on its relationship to programmed cell death. Increased autophagy has been observed in ruptured rotator cuff tendon tissues, suggesting a causal relationship. We investigated whether autophagy occurs in human rotator cuff tenofibroblast death induced by oxidative stress and whether antioxidants protect against autophagic cell death. We used H2 O2 (0.75 mM) as oxidative stressor, cyanidin (100 µg/ml) as antioxidant, zVAD (20 µM) as apoptosis inhibitor, and 3-MA (10 mM) as autophagy inhibitor. We evaluated cell viability and known autophagic markers: LC3-II expression, GFP-LC3 puncta formation, autolysosomes, and Atg5-12 and Beclin 1 expression. H2 O2 exposure increased the rates of cell death, LC3-II expression, GFP-LC3 puncta formation, and autolysosomes. After we induced apoptosis arrest using zVAD, H2 O2 exposure still induced cell death, LC3-II expression, and GFP-LC3 puncta formation. H2 O2 exposure also increased Atg5-12 and Beclin 1 expressions, indicating autophagic cell death. However, cyanidin treatment reduced H2 O2 -induced cell death, LC3-II expression, GFP-LC3 puncta formation, and autolysosomes. Cyanidin and 3-MA similarly reduced the cell-death rate, and Atg5-12 and Beclin 1 expression. This study demonstrated that H2 O2 , an oxidative stressor, induces autophagic cell death in rotator cuff tenofibroblasts, and that cyanidin, a natural antioxidant, inhibits autophagic cell death.

MATERIALS
Product Number
Brand
Product Description

Supelco
Hydrogen peroxide solution, ≥30%, for trace analysis
Sigma-Aldrich
Hydrogen peroxide solution, 34.5-36.5%
Sigma-Aldrich
Hydrogen peroxide solution, tested according to Ph. Eur.
Sigma-Aldrich
Hydrogen peroxide solution, contains potassium stannate as inhibitor, 30-32 wt. % in water, semiconductor grade, 99.999% trace metals basis
Sigma-Aldrich
Hydrogen peroxide solution, 30 % (w/w) in H2O, contains stabilizer
Sigma-Aldrich
Hydrogen peroxide solution, SAJ first grade, ≥30.0%
Supelco
Hydrogen peroxide solution, 30 % (w/w), for ultratrace analysis
Millipore
Hydrogen peroxide solution, 3%, suitable for microbiology
Sigma-Aldrich
Hydrogen peroxide solution, contains ~200 ppm acetanilide as stabilizer, 3 wt. % in H2O
Sigma-Aldrich
Hydrogen peroxide solution, purum p.a., ≥35% (RT)
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 30 wt. % in H2O, meets USP testing specifications
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 30 wt. % in H2O, ACS reagent
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 35 wt. % in H2O
Sigma-Aldrich
Hydrogen Peroxide Solution, 30% (w/w), puriss. p.a., reag. ISO, reag. Ph. Eur.
Sigma-Aldrich
Hydrogen peroxide solution, 50 wt. % in H2O, stabilized
Sigma-Aldrich
Cyanidin chloride, ≥95% (HPLC)
Supelco
Cyanidin chloride, analytical standard
Cyanidin chloride, European Pharmacopoeia (EP) Reference Standard