My RAW cell is not responding for NO production after LPS stimulation for 24 h. Any suggestion on this?

I treated RAW cells by LPS at passage 5 and 6 for 24 hr. I used DMEM (10%FBS) with penstrep. Griess reagent was used to measure NO release. No repsonse after LPS stimulation for 24 hr. Any help?

16 November 2016 904 6 View