Chitosan-P Crma Nanoparticles Protect Against Cartilage Degradation Of Osteoarthritis In A Rabbit Model

Some reports have shown that CrmA could ameliorate the interleukin-1 beta induced osteoarthritis. In this study we investigated the effects of chitosan (CS)-CrmA nanoparticles (NPs) on metalloproteases expression (MMPs) in chondrocytes in vitro/in vivo and the underlying mechanism. CS-pDNA NPs were prepared by gel complex method and characterized. The expression of GFP and CrmA was detected by fluorescence microscope or western blot after the NPs were added into the culture medium of primary rabbit chondrocytes. Primary rabbit chondrocytes were treated with PBS, CS/pCDNA3.1 (+) or CS/pCDNA3.1 (+) CrmA NPs to analyze the changes of MMPs expression and apoptosis. Rabbit osteoarthritis (OA) models were established using anterior cruciate ligament transaction (ACLT) method. Nanoparticles including CS/pCrmA were injected into the rabbit joint once a week for one month after operation. All joint tissues were obtained to analyze the pathogenic changes, the expression levels of IL-1 beta, MMP-1, -3, -9, -13 by real-time RT-PCR, and cell apoptosis by TUNEL. The binding of CS and pDNA were verified by agarose gel electrophoresis. The in vitro release of pDNA in NPs at pH 2.0 and pH 7.0 presented a bi-phase kinetic release-curve. GFP and CrmA in CS/pDNA NPs were confirmed in rabbit primary chondrocytes. CS/pCrmA NPs can not only significantly inhibit apoptosis of the primary chondrocytes induced by IL-1 beta and the expression levels of MMP-1, -3, -9, and -13 compared with controls (P<0.05) but ameliorate the progression of osteoarthritis by inhibiting the primary chondrocytes apoptosis, which was further confirmed by histopathologic analysis. This study demonstrated that CS and CrmA in CS/pCrmA NPs synergistically inhibit the expression of MMPs, reduce chondrocyte apoptosis, and enhance the repair response of cartilage following cartilage insults. Altogether, CS/pCrmA NPs presented therapeutic potential for patients with osteoarthritis.