Abstract
Objective To investigate the treating-effect of vasoactive intestinal peptide (VIP) on osteoarthritis (OA) in vivo and the improving-effect on OA chondrocyte in vitro, then clarify the underlying mechanism. Methods The OA model on the SD rat knee was established by Hulth method, and the recombinant pcDNA3.1+ /VIP plasmid was also constructed. After the VIP plasmid were injected intra-articularly into OA rats for 1 month, the pathological changes of OA knee joint were observed by Hematoxylin-eosin (HE) staining. The levels of serum cytokines [tumor necrosis factor-α (TNF-α), interleukin (IL)-1, IL-2 and IL-6] were measured by enzyme linked immunosorbent assay (ELISA) kits. Meanwhile, OA chondrocyte were cultured in vitro, and treated by plasmid VIP. The proliferation of chondrocyte was determined by cell counting kit-8 (CCK-8) kits. The protein expressions of collagen type Ⅰ (Collagen Ⅰ), collagen type Ⅱ (Collagen Ⅱ) and nuclear factor (NF)-κB were evaluated by Western blotting. The mRNA expressions of matrix-degrading enzyme matrix metalloproteinase (MMP)-3 and matrix-degrading enzyme inhibitor tissue inhibitorof metalloproteinase (TIMP)-1 were determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Results VIP plasmid could effectively improve the pathological state of the OA ratskneejoint. In addition, before the OA rats treated by VIP plasmid, the level of serum TNF-α, IL-1, IL-2 and IL-6 were (185.3±9.1), (391.7±20.6), (169.8±10.8), (143.7±15.2) pg/ml; then treated by VIP plasmid the level of serum TNF-α, IL-1, IL-2 and IL-6 were (112.8±10.2), (298.2±15.9), (131.4±13.4), (81.6±13.4) pg/ml, the levels of serum cytokinesweresignificantly decreased. At the same time, the absorbance (A450 nm) of chondrocytein OA group and VIP-treat groupdeterminedby CCK-8 kit were 0.75±0.12, 1.38±0.14, respectively, suggesting that after the OA chondrocytes treated by VIP plasmid, the proliferation was obviously increased. The MMP-3 mRNA expression of chondrocytesin OA group and VIP-treat group were 2.48±0.24, 1.35±0.16, respectively; the TIMP-1 mRNA expression were 0.56±0.11, 0.85±0.09, respectively, suggesting that the MMP-3 expression was remarkably downregulated, and TIMP-1 expression was obviously upregulated by VIP plasmid. After the the protein expression of Collagen Ⅰ, Collagen Ⅱ and NF-κB in were evaluated by Western blotting, we found that the expression of Collagen Ⅰ and NF-κB in chondrocyteswere decreased, and the expression of Collagen Ⅱ in chondrocyteswas increased by VIP plasmid. Conclusion VIP could treat osteoarthritisto some extent via inhibiting NF-κB signal pathway. Key words: Vasoactive intestinal peptide; Plasmid; Osteoarthritis; Chondrocyte
Published Version
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