| Objective:Rheumatoid arthritis(RA) is a systemic autoimmune disease of unknown etiology.Most clinical patients characterized by acute or chronic arthritis,can lead to joint stiffness,deformity, or even functional incapacitation. This inflammatory autoimmune disease seriously affects the quality of life of patients.In recent years,glucocorticoid(GC) played a very important role in the treatment of RA, especially the use of low-dose GC to treat RA is becoming more and more widely accepted. Low-dose GC can quickly control inflammation and relieve joint symptoms,while GC has many adverse reactions especially on bone metabolism.Procollagen I N-terminal peptide(PINP) and C-terminal telopeptide of type I collagen(CTX-1) are typical markers of bone metabolism represent bone formation and resorption respectively.The aim of this study is to investigate the abnormal change of bone metabolism of RA through detecting the serum levels of PINP, CTX-1 and interleukin-6(IL-6).Methods:60 RA hospitalized patients were studied,including 30 patients without GC(NGC) and 30 patients application with low-dose GC(LGC) more than 3 months.All patients were treated by disease modifying antirheumatic drugs.All of these samples were consistent with the American Rheumatism Institute(ACR) and the European League Against Rheumatism(EULAR) RA classification standards revised in 2010.All patients were excluded cardiovascular disease,cerebrovascular disease,liver disease,organ function failure and other autoimmune disease. 20 cases of healthy people from Health Examination Center of the Third Hospital of Hebei Medical University were selected as the normal control group.The serum levels of PINP, CTX-1, IL-6 of all subjects were measured through avidin biotin peroxidase complex enzyme- linked immunosorbent assay(ABC-ELISA).The clinical indexes of RA patients were recorded such as gender, age,erythrocyte sedimentation rate(ESR), C-reactive protein(CRP), rheumatoid factor(RF), anti-cyclic citrullinated peptide(CCP) antibody,and calculated the 28-joint disease activity scale(DAS28).The differences of PINP,CTX-1 and IL-6 between RA group and normal control group,NGC group and LGC group were analyzed.Correlation analysis were made between the PINP and CTX-1 and IL-6 and clinical indexes.Statistical software SPSS19.0 for windows was used to analyze all date.The measurement data was expressed by the mean number±standard deviation( ±s).The t or t’ test was used for the comparison of two groups. Linear correlation analysis was performed for correlationship. P value<0.05 was considered statistically significant.Result:1 The general data description:The RA group comprised 60 patients, including 47 cases of female,13 cases of male. The mean age was(50.37±13.09) years(rang 22 to 71 years). RA-NGC group comprised 30 patients(23 cases of female and 7 cases of male).The mean age was(47.10±13.79) years(rang 22 to 70 years). RA-LGC group comprised 30 patients(24 women and 6 men). The mean age was(53.63±11.67) years(rang 27 to 71 years).The control group comprised 20 cases(16 cases of female and 4 cases of male).The mean age was(47.70±12.72) years(rang 26 to 72 years). There were no significant differences between the control group and RA group in gender and age(P>0.05).RA-NGC group and RA-LGC group were no differences in gender and age(P>0.05). The mean CRP, ESR, DAS28 in RA-NGC group were(41.98±37.14)mg/L,(68.40±27.50)mm/h,(5.63±0.95);the mean CRP, ESR, DAS28 in RA-LGC group were(34.60±28.04) mg/L,(58.17±24.93) mm/h,(5.31±1.21).There were no statistical significance between RA-NGC group and RA-LGC group in the levels of CRP,ESR and DAS28(P>0.05).2 The levels of PINP,CTX-1 and IL-6 in serum2.1 Compared RA group with control group: The levels of PINP,CTX-1 and IL-6 in RA and control group were(19.48±3.58)μg/L,(89.22±16.99) ng/m L,(60.71±11.46)ng/L and(17.27±3.22)μg/L,(75.35±12.83)ng/m L,(48.81 ±8.49)ng/L respectively, the levels of RA group were significantly higher than normal controls(P <0.05).2.2 Compared RA-NGC group with RA-LGC group: The levels of PINP,CTX-1 and IL-6 in RA-NGC group were(20.28±3.56)μg/L,(91.20± 17.27)ng/m L,(63.49±11.98)ng/L respectively,and in RA-LGC group were(18.67±3.47)μg/L,(87.24±16.76)ng/m L,(57.93±10.36)ng/L respectively. The serum levels in RA-LGC group were all lower than RA-NGC group,while there was no statistical difference in the two groups(P >0.05).2.3 The correlation between PINP,CTX-1 and IL-6 and clinical indicators: The serum level of PINP was no significant correlation with ESR(r=-0.059, P=0.654),CRP(r=0.047,P=0.721),DAS28(r=-0.141,P=0.282) and RF(r=-0.057,P=0.665). The serum level of CTX-1 was no significant correlation with ESR(r=0.048,P=0.714),CRP(r=0.053,P=0.688),DAS28(r=-0.031,P=0.816) and RF(r=-0.083,P=0.528). The serum level of IL-6 was positively correlated with ESR(r=0.659,P=0.000),CRP(r=0.427,P=0.001) and DAS28(r=0.359, P=0.005), while there was no significant correlation with RF(r=-0.096, P=0.466).2.4 The correlation of indicators between the levels of serum PINP, CTX-1 and IL-6:According to linear correlation analysis showed, there were significantly positive correlation between PINP and CTX-1(r=0.460,P=0.000), PINP and IL-6(r=0.225,P=0.045),CTX-1 and IL-6(r=0.388,P=0.000).Conclusion:1 The serum levels of PINP,CTX-1 and IL-6 in RA patients were significantly increased.The results suggest that bone turnover of RA patients increase.2 There were no significant differences between RA-NGC group and RA-LGC group in the levels of PINP and CTX-1.The results show that lowdose GC had not enormous influence to the bone turnover of RA.3 The serum level of PINP and CTX-1 were no significant correlation with inflammatory indicators,disease activity and RF,while the serum level of IL-6 was positively correlated with inflammatory indicators and disease activity,which suggested that IL-6 may play an important role in the occurrence and development of RA. At the same time it may be an important marker of the RA disease activity.4 There were significant positive correlation among the levels of PINP,CTX-1 and IL-6. It suggested that IL-6 may play an important role in the process of bone metabolism. |
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