Trophoblast expression of COX-1, COX-2, and A:HO-1. Representative blots for COX-1, COX-2, and HO-1 expression in control cells, cells treated with CoCl2 with or without pretreated with 1,25(OH)2D3. B: Relative COX-1, COX-2, and HO-1 expression after normalized by β-actin expression in each sample. ** p<0.01: cells treated with CoCl2 vs. control untreated cells; ## p<0.01: cells pretreated with 1,25(OH)2D3+ CoCl2 vs. cells treated with CoCl2. CoCl2 had no effect on COX-1 expression, but significantly increased COX-2 and HO-1 expression. Pretreatment of the cells with 1,25(OH)2D3 blocked CoCl2 induced COX-2, but not HO-1, expression.