Discussion of ROS Effects under In Vivo Conditions

It is extremely difficult to qualify a real role of ROS under in vivo conditions due to the following reasons  

There is normally a very complex environment comprising, in addition to HA, also a large variety of different proteins, low mass compounds such as amino acids or lipids as well as a variety of 

Under in vivo conditions, the majority of ROS is generated enzymatically in rather complex metabolic networks. This makes the assessment - which ROS is generated in what amount - very difficult. This particularly holds because there are also many effects of ROS on the related enzyme activities. 

Finally, there are many antioxidants present in biological tissues that show important effects, not only antioxidative but also pro-oxidative effects. 

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