Purchase this article with an account.
M.B. Pantcheva, V.A. Hanninen, N.R. Poulin, A.P. Dobberfuhl, C.L. Grosskreutz; Phosphorylation of Akt and Activation of Caspase 9 After Optic Nerve Crush In Rats . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3348.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: The purpose of this study was to determine the temporal course of alteration of phosphorylated Akt (pAkt) and caspase 9 activation after optic nerve crush in the rat (ONC). Methods: Male Brown-Norway rats were subjected to right (OD) ONC (2.5 -3.0 mm posterior to the globe). The left eye (OS) served as a control. Rats were sacrificed 1, 3, 5 and 8 days after ONC. Retinal protein was collected for Western blots and probed with polyclonal antibodies specific for pAkt, cytochrome c, procaspase 9 and cleaved caspase 9. Alpha-tubulin was used as a loading control. Results were analyzed by densitometry. The amount of pAkt, cytochrome c, procaspase 9 and cleaved caspase 9 were expressed as a ratio of the crush eye to the control eye (OD/OS). Results: Total retinal pAkt levels showed a tendency to decrease at day 5 after ONC (OD/OS = 0.45 ± 0.06, n = 4) and increased significantly at day 8 (OD/OS = 1.76 ± 0.23, n = 6, p<0.05). There was a significant increase in cytochrome c levels 3 days after ONC, which at day 5 returned to the levels presented at day 1 (day 1: OD/OS = 1.16 ± 0.22; day 3: OD/OS = 2.7 ± 1.01 ; day 5: OD/OS = 1.87 ± 0.97 p < 0.05, n = 6 at each time point). In addition, Western blot analysis showed a 1.46 ± 0.11 fold increase in cleaved caspase 9 levels five days after ONC (n = 6, p < 0.05). Total retinal procaspase 9 levels remained unchanged up to 8 days after ONC (n = 6 at 1, 3, 5 and 8 days). Conclusions: Our data confirm previous observations implicating a role for caspase 9 activation and for pAkt involvement after ONC. We extend these observations to further characterize the temporal sequence of their changes and suggest that ONC may induce an increase in pAkt levels at day 8 which may represent a neuroprotective response to the trauma.
This PDF is available to Subscribers Only