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Nitza Goldenberg-Cohen, Myles Brookman, Orit Barinfeld, Moran Fridman; The neuroprotective role of TNF-alpha receptors 1 and 2 in mouse model of optic nerve crush. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4405.
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© ARVO (1962-2015); The Authors (2016-present)
To examine the role of tumor necrosis factor alpha receptors (TNFαR1/R2) in an optic nerve crush (ONC) model by measuring retinal thickness, loss of retinal ganglion cells (RGCs), and the expression levels of inflammatory, ischemic and apoptotic related genes.
Histological and Immunohistochemical analysis of TNFαR1 knock-out (KO), TNFαR2 KO and wild type (WT) mice were performed (n=3, n=6, n=7 respectively). All animals underwent ONC of the right eye (the left eye served as a control). Retinal thickness was measured and the number of RGCs was calculated in 3 consecutive areas measuring 20µm each, every 10th section, total of 7-9 sections per eye. Mean values were calculated and compared to the healthy controls. Immunostaining with CD45, Vimentin and GFAP was performed.Molecular analysis was performed on mRNA extracted from the retina by real time quantitative polymerase chain reaction (RT-qPCR) of TNFαR1/2 KO mice (n=3 each) and compared to WT mice (n=7). The expression levels of apoptotic associated (Bax, Bcl-2); inflammatory related (IL-6, MIP-2), and oxidative stress associated gene (SOD) were calculated.
On day 21, thinning of the retina was measured from 217(units) (±6) in the control retina to 186µm (±3) following ONC in WT mice. TNFRα1&2 mice had thinner retina measuring 177µm (±4) and showed minimal thinning to 174µm (±4) post ONC. In addition significant RGC loss (25%) was detected in the WT group but not in the transgenic mice (8%).On day 3, Bax and Bcl-2 levels in the retina increased (3.1+0.3 and 3.84+1.9 fold respectively), in the TNFαR1-KO but not in the in the TNFαR2-KO (0.8+0.4 and 0.57+0.2 respectively). WT mice showed decreased Bax (0.43±0.4) and increased Bcl-2(2.59±2.8) expression levels. TNFRα1-KO showed a slight elevation of MIP-2 (1.3-fold) as compared to reduced levels in the TNFαR2-KO and WT (0.63 and 0.7 respectively). SOD was elevated only in the TNFαR1-KO (3.71+2.8) and remained at baseline in the TNFαR2-KO and control group.
Both TNFαR1/2-KO mice showed a neuroprotective effect after a crush injury on histology. Molecular analysis revealed that TNFαR1-KO differs from TNFαR2-KO and control groups, suggesting that it plays a role in the post crush reaction. Blocking TNFαR1 immediately after trauma might facilitate vision preservation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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