The Comparison Study Of Green Tea And Pu-er Tea Extract’s Effects On The Expression Of ABCA1and ABCG1in Macrophages

Objective:In order to study the effect of green tea extract(GTE) and Pu-erh tea extract(PTE) on the expression of ATP binding cassetee transporter A1(ABCA1) and ATP binding cassetee transporter G1(ABCG1), and makes further effort to explore the role of the two teas in cholesterol metabolism.Methods:1. Macrophages were derived from THP-1by PMA.2. The best concentration of GTE and PTE which was used in the following experiment was identified by MTT assay.3. Macrophages were co-incubated with GTE and ox-LDL or PTE and ox-LDL. Oil Red O staining was used to observe the inhibitory effect of GTE and PTE on formation of foam cell.4. Macrophages were incubated with50μg/mL ox-LDL to derived foam cell. Foam cell were incubated with GTE and PTE respectively. The mRNA and protein of cells in each group were collected after24h and48h.5. The expression level of ABCA1and ABCG1mRNA were determineded by realtime-PCR,and the expression level of ABCA1and ABCG1protein were determineded by western blot.Result:1. The changes of cellular characteristics in different groups were showed by Oil Red O staining. The result showed that lipid droplets of GTE and PTE group were much lesser than the ox-LDL group, and the amount of foam cells in GTE and PTE group were much lower than the ox-LDL group (P<0.05),meanwhile the amount of foam cells of GTE group were much lower than PTE group (P<0.05);2. After24h, the mRNA and protein level of ABCA1and ABCG1in ox-LDL group, GTE group and PTE group are all markedly increased than control (P<0.01). The expression of ABCA1and ABCG1between GTE group and foam cell group were not significant, the expression of ABC A1between PTE group and GTE group and foam cell group were not significant, but the expression of ABCG1in PTE group was higher than ox-LDL (P<0.01) and GTE group (P<0.05);3. After48h, the mRNA and protein level of ABCA1and ABCG1in ox-LDL group have no significant difference with the control group. The expression of ABCA1and ABCG1in GTE and PTE group were still higher than control group and foam cell group (P<0.01), and the expression of ABCG1in PTE group was higher than GTE group (P<0.05)Conclusion:1. Macrophages incubated with50μg/mL ox-LDL for48h can form foam cells;2. GTE and PTE can inhibit the formation of foam cell, and the inhibit effect of GTE is better than PTE;3. GTE and PTE can increase the expression of ABCA1and ABCG1, and the effect of PTE is better than GTE. We infer that GTE and PTE inhibit the formation of foam cells by promoting the expression of ABCA1and ABCG1.