Kun Luo1, Neng-Wu Zhao2, Kun Cai1, *
1School of Basic Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550025, China - 2School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550025, China
Objective: To investigate the effect of ginkgolide B on diabetic atherosclerosis and its mechanism.
Methods: Raw264.7 macrophages were incubated in a culture medium containing PGEs (50 μg / mL) for 24 h and were intervened by ginkgolide B and PPARγ inhibitors. Oil red O staining was used to detect the formation level of foam cells, and the cholesterol content was quantitatively detected by a cholesterol content detection kit after ethanol dissolution. Flow cytometry was used to detect the expression of scavenger receptors and cholesterol uptake on the surface of macrophages. Cholesterol efflux was measured using a multi-functional microplate reader and a fluorescent reading method, and Western Blotting was used to detect the expression of PPARγ, ABC transporter, nCEH and ACAT-1. Elisa was used to detect the cytokine content in the supernatant, and the protein content in the cell was normalised with lysate.
Results: Studies have shown that advanced glycosylation products (AGEs) can inhibit PPARγ expression in macrophages, whereas ginkgolide B significantly increases PPARγ expression. Ginkgolide B can inhibit the formation of AGEs exposure-induced foam cells by activating the PPARγ signalling pathway, while significantly reducing the total cholesterol and cholesterol ester levels in macrophages. Further in-depth investigation shows that ginkgolide B can significantly inhibit the expression of scavenger receptors SR-A and CD36 by activating the PPARγ signalling pathway, as well as the expression of lipid conversion- and storage-related proteins such as nCEH and ACAT-1, thereby inhibiting phagocytic cholesterol uptake and storage. In addition, ginkgolide B can significantly elevate the expression of lipid excretion metabolism-related transporters such as ABCG-1 and ABCA-1 by activating the PPARγ signalling pathway, thereby promoting cholesterol excretion in macrophages. The results also reveal that ginkgolide B can significantly reduce the secretion levels of AGEs-induced macrophage pro-inflammatory factors such as TNF-α, IL-1β and IL-6, as well as the secretion level of IL-10.
Conclusions: Ginkgolide B activates the PPARγ signalling pathway, inhibits the lipid uptake and storage of macrophages and promotes their excretion process, thereby promoting the formation of foam cells and exerting the effect of anti-diabetic atherosclerosis.
Ginkgolide B, PPARγ, diabetic atherosclerosis, foam cells.