I am treating TNF-a to produce ROS in HUVEC. I started with passage no. 5 and used up to passage no. 9. But not sure whether I am getting the same response.
Culturing of any primary cell-type results in the production of ROS. With age, the levels of ROS increase. Therefore, an early passage may give you more response upon treatment with TNF-a.
I think Nox1 is upregulated with increasing number of passages, whereas it is present, at most, in a very small amount in native endothelium. There is alteration in a lot of genes in the culture process.