Abstract Background Osteoarthritis (OA) is a degenerative disease related to cholesterol metabolism disorders. However, current therapies for OA are insufficient and no convincing disease-modifying OA drugs exist. Therefore, we aimed to elucidate the mechanism by which borojoa iridoid glycoside (BIG) inhibits chondrocyte apoptosis in OA. Methods Borojoa pulp was heated to 70 °C, and the main active substance in borojoa, BIG, was extracted by fractionation at an ultraviolet 254-nm absorption peak. Chondrocytes were identified by immunohistochemistry and visualized by immunofluorescence confocal microscopy. The proliferation of chondrocytes cultured with BIG was determined by MTS assay. The apoptosis of chondrocytes cultured with BIG was tested by Annexin V-FITC/PI, and the cytokine, protein, and cholesterol levels in chondrocytes were detected by ELISA, RT‒qPCR, Western blot, and biochemistry analyses. Protein‒protein interactions were verified by a coimmunoprecipitation (Co-IP) assay. Results BIG promoted chondrocyte proliferation and reduced apoptosis in vitro. BIG induced an alteration of the total RNA profiles in chondrocytes, and bioinformatic analysis showed that BIG inhibited chondrocyte apoptosis by promoting c-MYC expression; KEGG analysis confirmed that BIG-inhibited apoptosis was enriched in the cell cycle pathway. Flow cell cycle experiments confirmed that BIG promoted chondrocyte proliferation by significantly increasing the S phase cell number. The c-MYC inhibitor 10058-F4 stimulated the increased expression of IL-1β, IL-6, TNF-α, and AGEs and suppressed the cholesterol metabolism, which promoted chondrocyte apoptosis and autophagy. Co-IP analysis showed that BIG promoted the interaction of c-MYC and CH25H, Bcl-2, which suggests that BIG could inhibit chondrocyte apoptosis in part by enhancing c-MYC-mediated cholesterol metabolism. Conclusions This study confirmed that BIG promotes chondrocyte proliferation and inhibits apoptosis and autophagy, and BIG improving OA is associated with cholesterol metabolism. The results identify a potential mechanism by which BIG enhances c-MYC-mediated CH25H regulation of cholesterol metabolism in vitro and suggest that BIG might be a promising new drug against OA.
Borojó (Borojoa patinoi Cuatrec) fruit has recently been shown to have a variety of health benefit, but the mechanisms have been little studied. The aim of this study was to investigate the effect of 4,8-dicarboxyl-8,9-iridoid-1-glycoside (388) on proliferation and differentiation of embryonic neural stem cells (NSCs).NSCs were treated with 388 and stem cell differentiation was determined by western blotting and immunofluorescence staining. The role of MeCP2 in 388-mediated embryonic NSCs differentiation was examined.The results showed that in the presence of mitogen when NSCs proliferated and maintained their multipotency, treatment with 388 did not affect the viability of NSCs. Following mitogen withdrawal to initiate NSC differentiation, treatment with 388 at the doses of 10 and 50 μg/mL significantly increased neural differentiation in both cortex and spinal cord-derived culture. 388 also significantly up-regulated MeCP2 expression. The expression of the neuronal and oligodendrocytic markers was enhanced after addition of 388 in the differentiation culture. However, knockdown of MeCP2 results in inhibition of NSC differentiation, and the pro-differentiation effect of 388 was mostly abolished.This study confirmed that 388 stimulates differentiation of NSCs and identifies its mechanism of action by upregulating MeCP2.
Objective To observe the biocompatibility of a biomimetic designing of a multi-grade compositions in repairing articular cartilage and subchondral bone in animal bodies and repair the fullthickness defects in articular cartilage with the compositions and to study the regenerated cartilage histomorphologically. Methods Biocompatibility study: Acute general toxicity test, Haemolysis test, subcutaneous implantation test and chronic toxicity test. Articular cartilage defects repaired experimental study :The models of defects in articular cartilage were made artificially in both condylus lateralis femoris of mature rabbits. Implanted with the biomimetic designing of a multi grade compositions randomly at one side as the experimental group and the other side were untreated as the control group. The rabbits were killed at 4, 6, 8and 12 weeks after operation, respectively, with 6 ones at each time, and the macroscopic, histological, ultrastroctural examinations and semi-quantity cartilage scoring employing Wakitanifa repaired cartilage value system were performed. Results Biocompatibility study: (1) The rabbits' weight in experimental group kept growing .(2) Haemolysis rate of rats to different concentrations of diffusion solution was＜5%.(3) In chronic toxic reaction, rabbits' liver and kidney function was not different compared with the control groups at 12weeks and the index before operation. Articular cartilage defects repaired experimental study: 4-8 weeks after operation, the defects in the experimental group were partly filled with hyaline cartilage. Twelve weeks after operation, the defects in the experimental group were completely filled with mature hyaline cartilage.However, fibrous tissues were seen in the control group all the time. At 4, 6, 8, and 12 weeks postoperatively, the Wakitanifa cartilage scores were (7.60±0.98), (5.69±0.58), (4.46±0.85) and (4.35±0.12), respectively,in the experimental group and (10.25±1.05), (9.04±0.96), (8.96±0.88) and (8.88±0.68), respectively, in the control group. Differences between the control group and the experimental group were significant. Conclu sion The biomimetic designing of a multi-grade compositions has good biocompatibility and may induce cartilage regeneration to repair the full-hickness defects of articular cartilage.
Key words:
Cartilage; Wounds and injuries; Biocompatible materials
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