Abstract
Purpose::
Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) exert neuroprotective roles through their receptors, TrkB and p75, respectively. The purpose of the present study is to examine the expression of TrkB and p75 in TNF-α induced optic nerve degeneration.
Methods::
Eight-week-old Wistar rats were received intravitreal injection of 10 ng TNF-α or PBS into one eye. Changes of mRNA of BDNF, NGF, TrkB or p75 in the retina and the optic nerve were examined by real-time PCR 1 day and 2 weeks after TNF-α injection. The protein levels of TrkB and p75 in the retina and the optic nerve were examined by Western blot analysis and their localizations were detected by immunohistochemistry.
Results::
Real-time PCR and Western blot analysis showed no significant difference in both mRNA and protein levels of all factors in the retina between TNF-α-injected eyes and PBS-injected eyes 1 day and 2 weeks after injection. However, significant decreases of TrkB and p75 mRNA appeared in the optic nerve 1 day and 2 weeks after TNF-α injection compared with those after PBS injection. Western blot analysis also showed the decreases of TrkB and p75 protein levels in the optic nerve 1 day and 2 weeks after TNF-α injection. Immunohistochemistry revealed the decrease of p75 immunoreactivity in the optic nerve after TNF-α injection.
Conclusions::
Depletion of TrkB and p75 may be involved in the process of optic nerve degeneration induced by TNF-α.
Keywords: optic nerve • receptors • nutritional factors