Why after induction THP-1 monocyte to macrophage using the PMA as inductor, the RNA gel showed 3 bands of rRNA?

I’m working with induction of THP-1 monocyte to macrophage using 12 ng/mL of PMA as inductor, but when I realize the RNA extraction appeared 3 bands on gel, Why is it happens?

08 May 2018 8,950 2 View