Dear Amarendranath,

Since you are rather interested in microscopic evaluation, you can try hydroethidine. you can inject it to animal, before sacrifice (more correctly you can determine the timing dependant on your experiment). It is selectively oxidized by superoxide anion to give a fluorescent signal.

http://www.ncbi.nlm.nih.gov/pubmed/22485176

For non-microscopic measurement, you can make use of spin probes (or spin traps), where you can evaluate levels of different ROS by electron spin resonance spectrometry.

http://www.noxygen.de/

Good luck!

Dear Muammer,

Thanks a lot for your help. In your suggested paper of Zhang et al., (2012) mainly worked on hippocampus and cortex region of brain, but I am interested to see the changes of ROS from whole brain samples. Hope it will be helpful. Thanks again.

With regards,

Amarendranath.