Possible Mechanism Of Melatonin Involved Rheumatoid Arthritis

The melatonin(MLT) and tryptophan (Try) levels in serum and MLT level in urine from patients with rheumatoid arthritis( RA),aged from 45 to 60 years which were divided to three groups ,that was the active phase, the remission phase and healthy control group, according to the diagnosis standards of American College of Rheumatology (ACR)in 1987, were studied by high-performance liquid chromatogrphy (HPLC) with fluorimetric detection method and amino-acid analyzer respectively. We not only observed the correlation method for studying the MLT and Try level in serum among the three groups , but also discussed the relationship between some clinical parameters and the MLT and Try levels in serum among the three groups. The results showed that the serum MLT level in RA patients with active phase (C I2~ ~=3.2?.O pgIml;C0~~,=96.9?5.1 pg/mI) was obviously lower than that in group with remission phase(C12. 00=14.6 ?8.1 pg/ml;C0 ~202.3 ?78.4 pg/mi) and in normal healthy group(C12. ~~25.4?10.2 pg/ml;C0~=289.6?98.5 pg/mi). Also, the difference between them was highly significant(P<0.0 1). The Try levels fluctuate in the three groups as above, but it seemed that it did not have a good concordance compared with the MLT levels. There existed a big difference (P<0.05) in Try levels of serum between RA patients in active phase (C12. ~~=42.8?15.7 i?g ml~?C000=63.2?1.4 Li g ~nV? and in remission phase(Ci2.c~=25.6?10.8 1-t g 禪P?C000=17.2?10.1 I~ g 秐t?. The correlation analysis showed that there existed a positive correlation (r=+0.76) 5 between MLT concentrations in serum and in urine, and there exists a negative correlation (r=-O.65) between Try and MLT level in serum in active phase. The results showed that the synthesis of the MLT had been inhibited to some extent in active phase. The lower the MLT level, the less the use of the Try for the body. It suggests that MLT may have some relationship with the episode of RA patient. Besides, the episode of the morning stiffness for RA patients accompanied with the sudden decrease of MLT in morning support the hypothesis that MLT may affect the analgesia mechanism directly. Furthermore, the results of the study showed that the raise of the Try levels in active phase for RA did not increase the level of the MLT. Further study should be done to determining the factors which inhib it the synthetic mechanism of MLT.