ABSTRACT
<p><b>AIM</b>To study the inhibitory effect of ginkgolide B (BN52021) on the PAF induced changes of chemotaxis of murine peritoneal macrophages and the related polymerization of F-actin.</p><p><b>METHODS</b>Chemotaxis assays were performed using a modified 48-well Boyden chamber. Actin polymerization of murine peritoneal macrophages was analyzed by flow cytometry using a specific fluorescent stain.</p><p><b>RESULTS</b>Peritoneal macrophages significantly migrated toward platelet-activating factor (PAF) through a micropore filter; however, in the presence of PAF receptor antagonist BN52021 (0.01 nmol x L(-1) -0.1 micromol x L(-1)), the migration was significantly inhibited. Moreover, BN52021 inhibited the actin polymerization of murine peritoneal macrophages induced by PAF in the presence of Ca2+, but not in Ca2+ -free medium.</p><p><b>CONCLUSION</b>The results suggested that preventing polymerization of F-actin may be a pathway by BN52021 to inhibit the chemotaxis of macrophages, and this effect seems to be Ca2+ dependent. The data further indicated that inhibition of PAF induced macrophage chemotaxis is an important mechanism underlying the anti-inflammatory action of BN52021.</p>
Subject(s)
Animals , Mice , Actins , Metabolism , Chemotaxis, Leukocyte , Diterpenes , Pharmacology , Ginkgo biloba , Chemistry , Ginkgolides , Lactones , Pharmacology , Macrophages, Peritoneal , Metabolism , Physiology , Mice, Inbred C57BL , Plants, Medicinal , Chemistry , Platelet Activating FactorABSTRACT
<p><b>AIM</b>To investigate the inhibitory effect of ginkgolide B on angiogenesis in chronic inflammation and the possible mechanisms.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>