银杏内酯B对慢性炎症血管生成的抑制作用

目的研究银杏内酯B对慢性炎症血管生成的作用及部分作用机制。方法比色法测定小鼠慢性肉芽肿气囊模型血管生成指数，组织形态学方法检测气囊病理变化；放射免疫方法测定白介素-1β(IL-1β)含量；L929生物测定法测定肿瘤坏死因子(TNF-α)含量；RT-PCR法检测IL-1β和TNF-α mRNA的表达。结果银杏内酯B可显著抑制模型小鼠的血管指数，与病理观察结果相符；银杏内酯B可显著抑制模型小鼠血清中IL-1和TNF-α的分泌；能显著抑制PMA诱导的U937细胞IL-1β和TNF-α的分泌及其mRNA的表达。结论银杏内酯B能抑制小鼠慢性炎症性血管生成模型的血管生成，能抑制促血管生成细胞因子IL-1β和TNF-α的转录及表达，这可能是其抑制慢性炎症血管生成的机制之一。

Inhibitory effect of ginkgolide B on angiogenesis in chronic inflammation

AIM: To investigate the inhibitory effect of ginkgolide B on angiogenesis in chronic inflammation and the possible mechanisms. METHODS: The murine chronic granulomatous air pouch model was used to observe the anti-angiogenesis effect of ginkgolide B. The vascular index was determined by colorimetry of carminic acid, and angiogenesis was observed by histology method. The interleukin-1beta (IL-1beta) levels in mice serum and in supernatants of U937 cell culture stimulated by phorbol 12-myristate 13-acetate (PMA) were detected by radioimmunoassay (RIA). The tumor necrosis factor-alpha (TNF-alpha) levels in mice serum and in supernatant of U937 cell culture were measured by cytotoxicity bioassay. The mRNA expression of IL-1beta and TNF-alpha of U937 cell culture was investigated by RT-PCR. RESULTS: Oral administration of ginkgolide B 25 and 100 mg x kg(-1) was shown to significantly inhibit the vascular index of murine chronic granulomatous air pouch model with the inhibitory rate of 22.52% and 25.29%, respectively. This result was supported by histological observation. Concomitantly, the IL-1beta levels in mice serums were also significantly decreased with the inhibitory rate of 50.61% and 58.66%; so were the TNF-alpha levels with the inhibitory rate of 28.91% and 52.41%. Ginkgolide B at concentration of 1 x 10(-5) to 1 x 10(-8) mol x L(-1) could also reduce both the IL-1beta and TNF-alpha contents in the supernatants of U937 cell culture stimulated by PMA, but the scopes of changes were much different. For IL-1beta the IC50 was 1.93 x 10(-8) mol x L(-1), while ginkgolide B at concentration of 1 x 10(-5) mol x L(-1) only decreased the release of TNF-alpha by 25.99%. Furthermore, ginkgolide B at concentrations of 1 x 10(-5) to 1 x 10(-7) mol x L(-1) was shown to significantly inhibit TNF-alpha mRNA expression of U937 cells; and at concentrations of 1 x 10(-5) and 1 x 10(-6) mol x L(-1) could inhibit IL-1beta mRNA expression. CONCLUSION: Ginkgolide B was shown to significantly inhibit angiogenesis of the murine chronic granulomatous air pouch model, reduce the IL-1beta and TNF-alpha levels in mice serums, and significantly inhibit IL-1beta and TNF-alpha mRNA expression and protein secretion in supernatants of U937 cell culture. It was suggested that reduction of proangiogenic cytokines IL-1beta and TNF-alpha secretion may contribute to the anti-angiogenesis effect of ginkgolide B in the murine chronic granulomatous air pouch model.