sentence: After 24 hours , the cells were treated with DMEM-hg containing 5 % lipoprotein-deficient serum ( LPDS ) , with or without 1 % ( w / v ) hydroxypropyl - β - cyclodextrin ( HPCD , Trappsol ) , 10 μ M sodium compactin and 50 µ M sodium mevalonate at 37 ° C for 1 hour .