Osteoarthritis is a degenerative joint disease which primarily affects the articular cartilage and subchondral bones. Since there is an underlying localized inflammatory component in the pathogenesis of osteoarthritis, compounds like tocotrienol with anti-inflammatory properties may be able to retard its progression. This study aimed to determine the effects of oral tocotrienol supplementation on the articular cartilage and subchondral bone in a rat model of osteoarthritis induced by monosodium iodoacetate (MIA). Thirty male Sprague-Dawley rats (three-month-old) were randomized into five groups. Four groups were induced with osteoarthritis (single injection of MIA at week 0) and another served as the sham group. Three of the four groups with osteoarthritis were supplemented with annatto tocotrienol at 50, 100 and 150 mg/kg/day orally for five weeks. At week 5, all rats were sacrificed, and their tibial-femoral joints were harvested for analysis. The results indicated that the groups which received annatto tocotrienol at 100 and 150 mg/kg/day had lower histological scores and cartilage remodeling markers. Annatto tocotrienol at 150 mg/kg/day significantly lowered the osteocalcin levels and osteoclast surface of subchondral bone. In conclusion, annatto tocotrienol may potentially retard the progression of osteoarthritis. Future studies to confirm its mechanism of joint protection should be performed.
Chondrosenescence (chondrocyte senescence) and subchondral bone deterioration in osteoarthritic rats were analyzed after treatment with the estrogenic herb Labisia pumila (LP) or diclofenac. Osteoarthritis (OA) was induced in bilaterally ovariectomized (OVX) rats by injecting mono-iodoacetate into the right knee joints. Rats were grouped (n = 8) into nontreated OVX+OA control, OVX+OA + diclofenac (5 mg/kg) (positive control), OVX+OA + LP leaf extract (150 and 300 mg/kg) and healthy sham control. After 8 weeks' treatment, their conditions were evaluated via serum biomarkers, knee joint histology, bone histomorphometry, protein and mRNA expressions. The LP significantly reduced cartilage erosion, femur bone surface alteration, bone loss and porosity and increased trabecular bone thickness better than diclofenac and the non-treated OA. The cartilage catabolic markers' (matrix metalloproteinase (MMP)-13, RUNX2, COL10a, ERa, CASP3 and HIF-2 alpha) mRNA expressions were down-regulated and serum bone formation marker, PINP, was increased by LP in a dose-dependent manner. The LP (containing myricetin and gallic acid) showed protection against chondrosenescence, chondrocyte death, hypoxia-induced cartilage catabolism and subchondral bone deterioration. The bone and cartilage protective effects were by suppressing proteases (collagen break-down), bone resorption and upregulating subchondral bone restoration. The cartilage ER alpha over-expression showed a strong positive correlation with MMP-13, COL10 alpha1, histological, micro-computed tomography evidence for cartilage degradation and chondrosenescence.
Osteoarthritis (OA) is a joint disease characterized by degeneration of cartilage, intra-articular inflammation, remodeling of subchondral bone and joint pain. The present study was designed to assess the therapeutic effects and the possible underlying mechanism of action of Manjarix, a herbal combination composed of ginger and turmeric powder extracts, on chemically induced osteoarthritis in rats. An OA model was generated by intra-articular injection of 50 μL (40 mg mL-1) of monosodium iodoacetate (MIA) into the right knee joint of rats. After one week of osteoarthritis induction, a comparison of the anti-inflammatory efficacy of indomethacin at an oral dose of 2 mg kg-1 daily for 4 successive weeks versus five decremental dose levels of Manjarix (1000, 500, 250, 125, and 62.5 mg kg-1) was performed. Serum inflammatory cytokines, interleukin 6, interleukin 8, and tumor necrosis factor alpha; C-telopeptide of type II collagen (CTX-II) and hyaluronic acid (HA) were measured, along with weekly assessment of the knee joint swelling. Pain-like behavior was assessed and knee radiographic and histological examination were performed to understand the extent of pain due to cartilage degradation. Manjarix significantly reduced the knee joint swelling, decreased the serum levels of IL6, TNF-α, CTX-II and HA, and reduced the pathological injury in joints, with no evidence of osteo-reactivity in the radiographic examination. Manjarix also significantly prevented MIA-induced pain behavior. These results demonstrate that Manjarix exhibits chondroprotective effects and can inhibit the OA pain induced by MIA, and thus it can be used as a potential therapeutic product for OA.
Vernonia amygdalina (VA) is a medicinal tropical herb for diabetes and malaria and believed to be beneficial for joint pains. The antiosteorthritis effects of VA leaf in cartilage explant assays and on postmenopausal osteoarthritis (OA) rat model were investigated. The VA reduced the proteoglycan and nitric oxide release from the cartilage explants with interleukin 1β (IL-1β) stimulation. For the preclinical investigation, ovariectomized (OVX) female rats were grouped (n = 8) into nontreated OA, OA + diclofenac (5 mg/kg), OA + VA extract (150 and 300 mg/kg), and healthy sham control. Monosodium iodoacetate was injected into the knee joints to accelerate OA development. After 8 weeks, the macroscopic, microscopic, and histological images showed that the OA rats treated with VA 300 mg/kg and diclofenac had significantly reduced cartilage erosions and osteophytes unlike the control OA rats. The extract significantly down-regulated the inflammatory prostaglandin E2, nuclear factor κβ, IL-1β, ADAMTS-5, collagen type 10α1, and caspase3 in the OVX-OA rats. It up-regulated the anti-inflammatory IL-10 and collagen type 2α1 mRNA expressions, besides reducing serum collagenases (MMP-3 and MMP-13) and collagen type II degradation biomarker (CTX-II) levels in these rats. The VA (containing various caffeoyl-quinic acids, flavanone-O-rutinoside, luteolin, apigenin derivative and vernonioside D) suppressed inflammation, pain, collagenases as well as cartilage degradation, and improved cartilage matrix synthesis to prevent OA.