RESUMEN
Objective To explore the significance in judging the different clinical stages of relapsing polychondritis (RP) patients through examining the changes of aggrecanase and metabolic fragments of aggrecan.MethodsIn comparison with the control group (20 cases),40 patients were divided into the stable stage group (22 cases) and the active stage group (18 cases).The aggrecanase-generated neoeptitopes in cartilage matrix were analysed by immunohistochemistry and Western blot(WB) respectively.The mRNA and protein levels of aggrecanase-1,2 expressed in cartilage cells were measured by real-time reverse transcriptional polymerase chain reaction(RT-PCR) and WB respectively.The difference of these results among these three groups was analyzed accordingly.ResultsThe expression of aggrecanase-1,2 in mRNA level was measured by real-time RT-PCR.The values of aggrecanase-1,2 mRNA 2 -ΔΔC1 were 1.00 ± 0.26 and 1.00 ± 0.27 in control group,1.47 ± 0.11 and 1.57 ± 0.13 in stable stage group,2.09 ±0.12 and 2.09 ± 0.19 in active stage group respectively.By one-way ANOVA analysis,the difference between every two groups was statistically significant (F was 299.113 and 459.013,P ＜ 0.01 ).In comparison with control group,aggrecanase-1,2 increased significantly in both stable and active stage group (P ＜ 0.01 ) and aggrecanase-1,2 increased more significantly in active stage group than in stable stage group (P ＜ 0.01 ).The results from WB analysis indicated that aggrecanase-1,2 could not be detected in control group,and they were detectable in stable stage group and increased in active stage group at the relative molecular of 68 000 Da or 73 000 Da respectively.The aggrecanase-generated neoeptitopes were analyzed by WB as well.The results indicated that NITEGE and ARGSV could be detected in stable stage group and increased in active stage group at the relative molecular of 70 000 Da or 48 000 Da respectively,but there were no signals in control group.Similar with the previous WB results,no signals of NITEGE or ARGSV eptitopes were detected in normal cartilage matrix ( no red staining) by use of immunohistochemical staining.However,in stable stage group and active stage group,these eptitopes were apparently detected (obviously red staining).ConclusionWith the progression of the RP,the activity of the aggrecanase is enhanced,and the degradation of the aggrecan is increased,associated with the severity of the disease.