Using a model of optic nerve ischaemia, this study investigated
oxygen-
glucose deprivation (OGD) on isolated rat optic nerve segments cultured in vitro. Thereafter, the effect of antisense
oligodeoxynucleotides (ASODN) specific to the
gap junction protein connexin43 (
Cx43) was evaluated in this same model. Following exposure to OGD for 2 hours, optic nerves were maintained in interphase organotypic culture with and without exposure to
Cx43 ASODN. Optic nerves were sectioned at 2 hours, 6 hours, and at days 1, 2, 3 and 6 following culture. Cell death was quantified using
propidium iodide (PI) staining and specific markers for
Cx43, capillaries (
von Willebrand factor), astrocytes (
glial fibrillary acidic protein), microglia and endothelial cells (
isolectin B4) were used to evaluate these parameters in conjunction with digital light and confocal microscopy. In this model, up-regulation of
Cx43 was seen at 2 hours following exposure of the optic nerve to OGD and peaked at day 3.
Cx43 ASODN treatment dampened this up-regulation. Additionally, more PI labeled cells were found in the centre of control optic nerve segments than in treated nerves (p<0.01). Controls also showed evidence of capillary breakdown and increased numbers of astrocytes and activated microglia compared to
Cx43 ASODN treated nerves (p<0.05). Thus, the application of
Cx43 ASODN to post-ischaemic optic nerve segments significantly reduced the up-regulation of
Cx43 and, subsequently, the spread of injury and a resultant inflammatory response.
Cx43 up-regulation may play an important role in
optic nerve injury, offering a potential avenue for treatment in
optic neuropathy.