OBJECTIVE: To study the expression of interleukin-1 receptor in normal mice sciatic nerves and in transected sciatic nerves treated with or without extrinsic interleukin-1 locally at different periods. METHODS: Seventy-two KM mice were equally divided into two groups. All the left sciatic nerves were transected. The stumps in experimental group were soaked in liquid with interleukin-1, whereas those in control group without interleukin-1. Then all the stumps were repaired end to end. At the 3rd hour, 1st day, 3rd day, 7th day, 14th day, and 28th day after operation respectively, every proximal stump was dissected and the expression of interleukin-1 receptor was carried out by immunohistochemistry method (LSAB method). The expression level of interleukin-1 of ten normal sciatic nerves of mice was studied, too. RESULTS: Normal nerves showed interleukin-1 receptor expression on the membrane of Schwann cells. After nerve injury, the interleukin-1 receptor expression increased biphasically in both groups, but the intensity of increase was lower in the experimental group than in the control group. CONCLUSION: Schwann cell is the target cell of interleukin-1.
ObjectiveTo investigate the effect of phosphorylatable short peptide (pSP) conjugated chitosan (CS) (pSP-CS) mediated insul in-l ike growth factor 1 (IGF-1) gene and human interleukin 1 receptor antagonist (IL-1Ra) gene local transfection on the repair of articular cartilage defect. MethodsCo-expression plasmid pBudCE4.1-IL-1Ra+IGF-1, single gene expression plasmid pBudCE4.1-IL-1Ra and pBudCE4.1-IGF-1 were constructed and combined with pSP-CS to form pSP-CS/ pDNA complexes. Thirty 3-month-old healthy male New Zealand white rabbits, weighing 2.0-2.5 kg, double legs were randomly divided into 5 groups (n=12). Lateral femoral condyle articular surface was only exposed in sham-operated group (group A); full-thickness cartilage defects were created in the articular surface of the lateral femoral condyle of the knee in 4 intervention groups: pSP-CS/pBudCE4.1 (group B), pSP-CS/pBudCE4.1-IL-1Ra (group C), pSP-CS/pBudCE4.1-IGF-1(group D), and pSPCS/ pBudCE4.1-IL-1Ra+IGF-1 (group E). At 1 week after operation, intra-articular injection of pSP-CS/pDNA complexes was administrated 2 times a week for 7 weeks in each intervention group, the same volume normal sal ine in group A. The general condition of animal was observed after operation, and rabbits were sacrificed at 8 weeks. Knee joint synovial fluid was collected to measure the concentrations of the IL-1Ra and IGF-1 by ELISA; mRNA expressions of Aggrecan, matrix metalloproteinase 3 (MMP-3), and MMP inhibitor 1 (TIMP-1) were detected by real-time fluorescent quantitative PCR; the chondrogenic phenotype of nascent cells in the damage zone was identified by alcian blue-periodic acid/schiff (AB-PAS) histochemistry and Aggrecan immunohistochemistry staining. ResultsThirty experimental rabbits all survived to the end of experiment, without infection and death. Large amounts of exogenous proteins of IGF-1 and IL-1Ra were detected in the synovial fluid of 4 intervention groups. There were significant differences between groups D, E and group A in IGF-1 protein expression, and between goups C, E and group A in IL-1Ra protein expression (P < 0.05). Aggrecan and TIMP-1 mRNA expressions were significantly up-regulated in group E, simultaneously MMP-3 mRNA expression was significantly down-regulated when compared with groups C and D (P < 0.05). Varying degrees of cartilage repair appeared in groups C, D, and E, showing positive staining of AB-PAS and Aggrecan, and group E had better results than groups C and D (P < 0.05); inflammatory cell infiltration and fibrous tissue prol iferation were seen in the defect region of group B, without significant cartilage repairing. ConclusionpSP-CS is an ideal gene del ivery system for cartilage defect gene therapy; IL-1Ra and IGF-1 double gene transfection has better biologic effect on cartilage defect repair.