Inhibitory effect of ginkgolide B on angiogenesis in chronic inflammation

AimTo investigate the inhibitory effect of ginkgolide B on angiogenesis in chronic inflammation and the possible mechanisms. MethodsThe 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-1β (IL-1β) 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-α (TNF-α) levels in mice serum and in supernatant of U937 cell culture were measured by cytotoxicity bioassay. The mRNA expression of IL-1β and TNF-α of U937 cell culture was investigated by RT-PCR. ResultsOral administration of ginkgolide B 25 and 100 mg·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-1β levels in mice serums were also significantly decreased with the inhibitory rate of 50.61% and 58.66%; so were the TNF-α levels with the inhibitory rate of 28.91% and 52.41%. Ginkgolide B at concentration of 1×10^-5 to 1×10^-8 mol·L^-1 could also reduce both the IL-1β and TNF-α contents in the supernatants of U937 cell culture stimulated by PMA, but the scopes of changes were much different. For IL-1β the IC50 was 1.93×10^-8 mol·L^-1, while ginkgolide B at concentration of 1×10^-5 mol·L^-1 only decreased the release of TNF-α by 25.99%. Furthermore, ginkgolide B at concentrations of 1×10^-5 to 1×10^-7 mol·L^-1 was shown to significantly inhibit TNF-α mRNA expression of U937 cells; and at concentrations of 1×10^-5 and 1×10^-6 mol·L^-1 could inhibit IL-1β mRNA expression. ConclusionGinkgolide B was shown to significantly inhibit angiogenesis of the murine chronic granulomatous air pouch model, reduce the IL-1β and TNF-α levels in mice serums, and significantly inhibit IL-1β and TNF-α mRNA expression and protein secretion in supernatants of U937 cell culture. It was suggested that reduction of proangiogenic cytokines IL-1β and TNF-α secretion may contribute to the anti-angiogenesis effect of ginkgolide B in the murine chronic granulomatous air pouch model.