Ginkgo Biloba Extract (Egb 761) Modulates Bleomycin-induced Acute Lung Injury in Rats

Abstract

The effect of Ginkgo biloba extract (EGb 761) on bleomycin (BLM)-induced acute lung injury was studied in rats. The responsiveness of isolated pulmonary arterial rings to 5-hydroxytryptamine (5-HT) as well as the levels of some relevant biochemical markers in the lung tissue were taken as evidence for the acute lung injury. BLM was given intraperitoneally at a dose of 15 mg/kg/day for five consecutive days. It was found that BLM treatment attenuated the vasoconstrictor effect of 5-HT on the isolated pulmonary arteries. In lung tissues BLM also elevated the level of lipid peroxides and enhanced the activity of glutathione peroxidase. On the other hand, the level of glutathione and the activity of alkaline phosphatase were reduced. Body weight, lung weight and tissue glutathione-S-transferase activity were, however, not altered. Oral administration of EGb 761 at a dose of 100 mg/kg/day for five consecutive days did not alter any of the chosen biochemical parameters in the lung tissue except for a slight reduction in alkaline phosphatase activity. However, treatment with EGb 761 reduced the responsiveness of the pulmonary artery to 5-HT. Administration of EGb 761 (100 mg/kg/day; po) two hours prior to BLM (15 mg/kg/day; ip), for five consecutive days blunted the occurrence of further reduction in the vasoconstrictor response of the pulmonary artery to 5-HT. Furthermore, EGb 761 tended to normalize BLM-induced alterations in the measured biochemical markers in the lung tissue. The apparent modulatory influence of EGb 761 on BLM-induced acute lung injury stems, at least in part, from its beneficial free radical scavenging properties that provide the extract with antioxidant activity.

Effects of Ginkgo biloba on plasma oxidant injury induced by bleomycin in rats

“…These data are in good agreement with Daba et al (2002). El-Khatib et al (2001) demonstrated that bleomycin in lung tissues increased the level of lipid peroxides and enhanced the activity of GSH-Px. In our data, GSH-Px activity in plasma was unchanged after bleomycin treatment.…”

“…Oxidative stress plays an important role in the development of fibrotic responses in the lung. Recent studies demonstrated that Ginkgo biloba treatment in rats improved lung fibrosis induced by bleomycin (El-Khatib et al, 2001;Daba et al, 2002). However, it is not clear whether plasma oxidant and anti-oxidant systems play a role in pulmonary fibrosis induced by bleomycin.…”

Antioxidants as Potential Therapeutics for Lung Fibrosis

“…In addition, lazaroids are protective against bleomycin-induced lung fibrosis in rats (49,132). A number of natural products that contain polyphenolic compounds, such as Ginko biloba extracts and curcumin, have been found to suppress lung oxidative stress and fibrosis in rats treated with bleomycin (48,67,93,152,207).…”

Potential Effects of Medicinal Plants and Secondary Metabolites on Acute Lung Injury

“…In a bleomycin-induced acute lung injury rat model, a G. biloba leaf extract (EGb 761) reduced the responsiveness and diminished the occurrence of further reduction in the vasoconstrictor response of the pulmonary artery due to 5-hydroxytryptamine (5-HT). Furthermore, EGb 761 normalized bleomycin-induced alterations in the measured lung tissue biochemical markers [68]. Additionally, in another study, EGb 761 reduced protein leakage, neutrophil infiltration, myeloperoxidase (MPO, a heme enzyme present in the primary granules of neutrophils), and metalloproteinase (MMP)-9 activities in an LPS-initiated ALI rat model.…”