Protective Effects of Annatto Tocotrienol and Palm Tocotrienol-Rich Fraction on Chondrocytes Exposed to Monosodium Iodoacetate

Abstract

Background: This study aimed to compare the chondroprotective efficacy and mechanism of annatto tocotrienol (AnTT) and palm tocotrienol-rich fraction (PT3) using SW1353 chondrocytes treated with monosodium iodoacetate (MIA). Methods: The chondrocytes were incubated with AnTT or PT3 in advance or concurrently with MIA for 24 h. The viability of the cells was tested with an MTT assay. The 8-isoprostane F2-α, extracellular matrix proteins, metalloproteinase and sex-determining region Y box protein 9 (SOX9) levels were determined using immunoassays. Results: AnTT and PT3 reversed an MIA-induced decrease in chondrocyte viability when incubated together with MIA (p < 0.05). Prior incubation with both mixtures did not produce the same effects. AnTT and PT3 cotreatment could suppress 8-isoprostane F2-α level in chondrocytes exposed to MIA (p < 0.01). Co-exposure to tocotrienols and MIA increased the type II collagen/type I collagen ratio in chondrocytes (p < 0.01). In addition, the co-exposure of AnTT and MIA for 24 h significantly upregulated SOX9, type II collagen and aggrecan levels (p < 0.05), which was not observed with co-exposure of PT3 and MIA, AnTT or PT3 exposure alone. Conclusion: AnTT and PT3 could prevent a reduction in chondrocyte viability following MIA exposure by reducing oxidative stress. In addition, AnTT might induce self-repair and anabolic activities in chondrocytes challenged with MIA.

The Role of Tocotrienol in Arthritis Management—A Scoping Review of Literature

“…Among the OA studies, one involved oral supplementation of palm tocotrienol (400 mg/kg/day for 6 months) among patients with OA (Kellgren–Lawrence score of 2 and 3) [ 46 ]; two studies involved oral supplementation of palm (100 mg/kg/day for 4 weeks) or annatto tocotrienol (50–150 mg/kg/day for 4 weeks) in rats with monosodium iodoacetate-induced OA [ 47 , 48 ]; another study used SW1353 chondrosarcoma cells exposed to monosodium iodoacetate and palm (25–50 µg/mL for 24 h) or annatto tocotrienol (10–20 µg/mL for 24 h) in the experiment [ 49 ]. Glucosamine sulphate was used as the positive control in the in vivo studies [ 46 , 47 , 48 ].…”

“…The in vitro study demonstrated that tocotrienol, especially the annatto derivative, could elicit the cellular protective mechanism of SW1353 chondrocytes against damage by monosodium iodoacetate. This was evidenced by an increased collagen II type α1 to collagen I type α1 ratio, and increased SRY-box transcription factor 9 and aggrecan expression in chondrocytes exposed to both monosodium iodoacetate and annatto tocotrienol [ 49 ]. These markers indicated the differentiation and functionality of chondrocytes [ 50 , 51 ].…”

“…Furthermore, both palm and annatto tocotrienol also ameliorated oxidative stress in chondrocytes exposed to monosodium iodoacetate. However, the same study demonstrated that pretreatment of chondrocytes with both forms of tocotrienol for 24 h before monosodium iodoacetate did not protect the cells from damage [ 49 ].…”

Transcriptomic Analysis of the Anticancer Effects of Annatto Tocotrienol, Delta-Tocotrienol and Gamma-Tocotrienol on Chondrosarcoma Cells

“…The cytotoxicity of tocotrienols was determined using the yellow tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) according to previous studies with slight modification [ 6 ]. Briefly, 100 µL of human chondrosarcoma SW1353 cells with a density of 5 × 10 4 cells/mL were seeded in a 96-well plate with complete media for 24 h. On the next day, the media were removed and replaced with 100 µL of complete media with a series of concentrations of tocotrienol (10–50 µM) for another 24 h. At the end of the treatment, 20 µL of MTT solution (5 mg/mL) was added to each well and then further incubated for another 4 h inside a 37 °C incubator.…”

“…On the other hand, rice bran oil contains lesser vitamin E (around 300 mg/kg) with around 25% tocopherols, 17% tocotrienols and a negligible amount of γ-tocotrienol (γ-T3) [ 5 ]. Vitamin E extracted from annatto beans is unique in composition with the absence of tocopherol but 10–16% γ-T3 and 84–90% of δ-tocotrienol (δ-T3) [ 6 , 7 ]. Plant oil-derived tocotrienol or tocotrienol-rich fraction (TRF) is a more viable candidate for commercialization than their pure isomers which require complicated and expensive isolation procedures [ 5 ].…”