I am trying to induced Aβ secretion in BV-2 cell line by adding LPS into cell culture.

I used freshly prepared 10μg/mL LPS at first, and after 48h treatment, I collected the medium and performed ELISA to test Aβ secretion. However, the O.D value is very close to blank value. Then I increased LPS concentration to 20µg/mL, but the Aβ induction also failed.

I observed that there are not obvious cell death after 48h LPS treatment, in both 10 µg/mL and 20µg/mL group, that is weird.

I purchased LPS from Sigma (https://www.sigmaaldrich.com/TW/en/product/sigma/l4391?context=product).

Does anyone have any idea? Thanks!