| AIM:Collagen-induced arthritis were established in Wistar rats to investigate the effects of tetramethylpyrazine on arthritis, angiogenesis and expression of vascular endothelial growth factor in synovium. At the same time, abdominal macrophages were obtained from Wistar rats to investigate the effects of tetramethylpyrazine on the secretion of vascular endothelial growth factor and the expression of hypoxia-inducible factor-1 after the macrophages were stimulated by lipopolysaccharides. METHODS: 1. Collagen-induced arthritis animal models were established in Wistar rats by intradermal injections of chicken collagen typeⅡemulsified with incomplete Freund's adjuvant. Rats with established collagen-induced arthritis were treated with 100mg/kg?d,50 mg/kg?d and 10mg/kg?d cyclosporine A, ig, continuously for 30 days . The effects of treatment were monitored by measurement of arthritis scores, footpad thickness, pathological characteristics of joint by histopathological techniques and joint roentgenography, the ultrastructure of vascular endothelial cells in synovium by transmission electron microscope investigation, microvessels density by immunohistochemical test as well as the expression of vascular endothelial growth factor in synovium by RT-PCR and Western Blot analysis. 2. Abdominal macrophages were stimulated by 10μg/ml lipopolysaccharides, and 100μg/ml,10μg/ml,1μg/ml tetramethylpyrazine and 0.5μg/ml dexamethasone were added. ELISA method was used to investigate the effect of tetramethylpyrazine on the secretion of vascular endothelial growth factor by macrophages, MTT method was used to investigate the effect of tetramethylpyrazine on the proliferation of macrophages, and Western Blot analysis was used to investigate the effect of tetramethylpyrazine on the expression of hypoxia-inducible factor-1α in macrophages. RESULTS: 1. Compared with collagen-induced arthritis models, 100mg/kg?d tetramethylpyrazine could remarkably reduce the arthritis index from 7.42±1.59 to 6.57±1.06 (P<0.05) after 30 day' treatment; however, 50 mg/kg?d tetramethylpyrazine had no remarkable effect on the arthritis index, which was 7.14±1.15 (P>0.05). The footpad thickness of 100mg/kg?d tetramethylpyrazine group was 8.46 ± 1.56mm, compared with collagen-induced arthritis models group 10.12 ± 1.89mm, there was significant difference (P<0.05); The footpad thickness of 50mg/kg?d tetramethylpyrazine group was 9.89 ± 2.02mm, compared with collagen-induced arthritis models group, there was no significant difference (P>0.05). Joint roentgenography and transmission electron microscope investigation showed that 100mg/kg?d tetramethylpyrazine also could improve the radiographic findings in the joint and ultrastructure findings in the vascular endothelial cells, however, 50mg/kg?d tetramethylpyrazine had no remarkable effects on them. Immunohistochemical test showed that, compared the model group 50.41±4.78, positive cell percent of the vascular endothelial growth factor in synovium of 100mg/kg ? dtetramethylpyrazine group reduced to 44.37± 5.01, the difference is remarkable (P<0.01), but 50mg/kg?d tetramethylpyrazine had no effect on it, whose positive cell percent of the vascular endothelial growth factor was 47.01±3.71 (P>0.05). At the same time, compared the model group 29.22±5.07, the microvessel density of 100mg/kg?d tetramethylpyrazine group reduced to 24.79±4.22 (P<0.05), but 50mg/kg?d tetramethylpyrazine had no effect on it, whose microvessel density was 27.13±4.73 (P>0.05). RT-PCR and Western Blot analysis showed that 100mg/kg ? d tetramethylpyrazine could reduce the expression of vascular endothelial growth factor mRNA and protein in synovium, the OD value remarkably reduced from 1.10±0.11 to 0.39±0.17 (P<0.01), or from 0.71±0.29 to 0.39±0.14 (P<0.01), but the OD value of 50mg/kg?d tetramethylpyrazine was 1.08±0.09, or 0.68±0.25, there was no significant difference between 50mg/kg?d tetramethylpyrazine group and model group. 2. 100μg/ml and 10μg/ml tetramethylpyrazine, but not 1μg/ml tetramethylpyra...
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