Biochemical Determination of Oxidative and Antioxidant Activities in the Retina-Choroid of the Super P53 Mice

Abstract

Purpose:: The tumor suppressor p53 plays a pivotal role in protection from cellular damage and response to stressors. Activation of p53 may result in either beneficial (DNA repair) or detrimental (apoptosis) consequences for cells. The main purpose of this study is to analyze the intrinsic degree of oxidative stress of the retina-choroid from mice overexpressing p53 gene.

Methods:: We have used mice of the strain C57BL/6 aged 12 months in two groups: 1) super p53 (sp53 G) and 2) wild-type controls (wt G). Mice were anestesyzed in eter atmosphere to obtain the eyeballs that were washed, disected and soaked in PBS to freeze at -85ºC until processing. Three to five retina-choroid by each eppendorf were homogenated and recorded by groups to determine by enzymatic-colorimetric methods the oxidative and antioxidant activities and the nitric oxide synthesis.

Results:: A significant increase in free radical formation (via lipid peroxidation; p<0,001), antioxidant activity p<0,001) and nitric oxide synthesis (p<0,001) were found in the retina-choroid samples from transgenic super p53 mice when compared to the respective control. All data suggest that the intrinsic degree of oxidative stress may modulate cell susceptibility to p53-dependent induction of apoptosis, and also the ability of antioxidants for protecting cells against apoptosis.

Conclusions:: The presence of an extra copy of p53 gene strongly suggests that these mice are more resistant to oxidative stress as compared to the controls. It has been taken into account the use of the experimental model of transgenic mice to study cell resistance to neurodegenerative processes with vascular component, such as glaucomatous optic neuropathy or age related macular degeneration.

Keywords: gene/expression • apoptosis/cell death • retina