Jiang_2011_Zhonghua.Yi.Xue.Za.Zhi_91_111

OBJECTIVE: To observe the effects of soluble epoxide hydrolase inhibitors-tAUCB on the uptake and degradation of ox-LDL in adipocytes.
METHODS: 3T3-L1 preadipocytes were induced into differentiation and maturation. After a 24-hour starvation, the cells were stimulated with 100 ng/ml LPS and then tAUCB at various concentrations (0 - 100 micromol/L)were added for 24 h, or preincubated with the PPARgamma (peroxisome proliferators activated receptor gamma) antagonist GW9662 (5 micromol/L). And the 0 micromol/L tAUCB-treated group was taken as the blank control group. Then the uptake and degradation of ox-LDL in cells were measured by radioligand assay. The mRNA expressions of PPARgamma and CD36 were detected by real-time PCR (polymerase chain reaction). And the intracellular levels of protein expression of PPARgamma and CD36 were detected by Western blot. While ADP and TNF-alpha in supernatant were detected by ELISA.
RESULTS: tAUCB could dose-dependently increase the uptake and degradation of ox-LDL in adipocytes. When stimulated with 10, 50, 100 micromol/L tAUCB, the uptake levels of ox-LDL were (35.6 +/- 1.1)ng/mg, (39.8 +/- 1.6) ng/mg, (42.6 +/- 1.4) ng/mg cell protein and the degradation levels of ox-LDL (2879 +/- 54) ng/mg, (3082 +/- 56) ng/mg, (3226 +/- 68) ng/mg cell protein. And they were significantly higher than those of the control group (28.9 +/- 1.2) ng/mg, (2791 +/- 54) ng/mg respectively (all P < 0.05). However, after preincubation of GW9662, the uptake of ox-LDL were decreased to (30.6 +/- 1.3) ng/mg, (31.1 +/- 1.7) ng/mg, (32.1 +/- 1.8) ng/mg cell protein whereas the degradation of ox-LDL decreased to (2788 +/- 53) ng/mg, (2824 +/- 70) ng/mg, (2874 +/- 70) ng/mg cell protein. And the difference was statistically significant when it was compared with the corresponding tAUCB-treated group. With the rising concentration of tAUCB, tAUCB could dose-dependently increase the mRNA and protein expression of CD36 and PPARgamma. tAUCB could dose-dependently decrease the levels of TNF-alpha and increase the levels of ADP in adipocytes. GW9662 could significantly inhibit those effects of tAUCB and reduce the uptake and degradation of ox-LDL and the expression of PPARgamma and CD36 in adipocytes. CONCLUSION: tAUCB can up-regulate the PPARgamma expression in adipocytes and promote the uptake and degradation of ox-LDL in adipocytes via PPARgamma-CD36 pathway. Meanwhile, the levels of ADP and TNF-alpha may be mediated through the activation of PPARgamma.