Fig. 4

Effect of Cur on TRPA1 protein expression and calcium influx in Caco-2 cells by activating the TRPA1 channel. A Caco-2 cells were incubated with different concentrations of Cur (0, 5, 10, 20, 50, and 100 µM) for 48 h, and TRPA1 protein expression was then determined by Western blotting (n = 6). B Caco-2 cells were then incubated with the indicated concentrations of MC (100 µM), Cur (10 µM), and HC (9 µM) for 48 h, and Western blotting was used to detect TRPA1 protein expression (n = 5). C Intracellular Ca²⁺ levels in Caco-2 cells exposed to Cur with or without HC exposure were detected by a Fluo-4 AM calcium assay kit (n = 3). D AUC of intracellular Ca²⁺ levels at different time periods. Data presented as mean ± SEM. ^*P < 0.05 vs control, ^***P < 0.001 vs control or Cur (D), ^#P < 0.05 vs MC, ^&&P < 0.01 vs MC + Cur. Cur, curcumin; TRPA1, transient receptor potential cation channel subfamily A member 1; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; MC, micellar cholesterol; HC, HC-030031; AUC, area under curve; SEM, standard error of the mean