Expression of insulin-like growth factor 1 receptor in rat retina following optic nerve injury

Abstract

ABSTRACT.Purpose: To investigate the apoptosis in retinal ganglion cells (RGCs) and insulin-like growth factor 1 receptor (IGF-1R) in the retina following optic nerve crush. Methods: Healthy Wistar rats (N = 70) were divided into two groups: a normal control group and an optic nerve injury group. Immunohistochemistry and flow cytometry were performed to detect the expression of IGF-1R and to measure the apoptosis of RGCs, respectively. Results: Immunohistochemistry revealed that at 1 hr after optic nerve injury, IGF-1R immunoreactivity began to increase and reached a maximal level at 24 hr (p < 0.05), where it remained elevated up to 14 days after injury. RGC apoptosis in the normal control group was 0.53%, while the apoptosis rate in the optic nerve injury group increased over time. The apoptosis rate in the optic nerve injury group was 1.4% at 1 hr, 4.4% at 6 hr, 5.2% at 12 hr and reached a maximal level (8.5%) at 24 hr. Subsequently, the rate declined to 1.9% 7 days after injury and 0.9% 2 weeks after injury. Conclusion: The IGF-1R immunereactivity in the retina increased after optic nerve injury. IGF-1R may regulate the apoptosis and regeneration of RGCs at different stages after optic nerve injury.

Subtype-Specific Regeneration of Retinal Ganglion Cells following Axotomy: Effects of Osteopontin and mTOR Signaling

“…We therefore combined AAV-OPN administration with intravitreal injection of a growth factor. We chose IGF-1 because it has neuroprotective and regeneration-promoting abilities in other contexts (Dupraz et al, 2013; Hollis et al, 2009) and because its receptor, IGF1R, is expressed by RGCs (Bu et al, 2013; Tagami et al, 2009; and see below). IGF-1 alone had no detectable effect on regeneration, but the combination promoted regeneration as effectively as shPTEN (Fig.…”

Chorio-retinal thickness measurements in patients with acromegaly

“…21,22 Optic nerve and peripapillary RNFL damage could occur in acromegaly owing to the compression of pituitary adenoma on optic chiasm, 4 optic nerve compression by enlarged retrobulbar tissues, 9 increased risk of sleep apnea, 5 systemic hypertension, 5 and papilloedema. 23 Nevertheless, in our study, there was no significant difference between acromegaly and controls, with respect to peripapillary RNFL thickness.…”

Insulin signalling promotes dendrite and synapse regeneration and restores circuit function after axonal injury

“…The rapid retraction of RGC dendrites is one of the earliest pathological changes in glaucoma ( Agostinone and Di Polo, 2015 ). Insulin receptors are abundantly expressed by adult RGCs ( Bu et al , 2013 ), and impairment of insulin signalling in these neurons inhibits neurite outgrowth ( Song et al , 2015 ). Insulin binding to its receptor activates phosphoinositide-3′ kinase (PI3K) and its target Akt leading to potent activation of the mammalian target of rapamycin (mTOR) complexes 1 and 2 (mTORC1 and mTORC2) ( Saxton and Sabatini, 2017 ).…”