Abstract
Purpose: :
Transpupillary thermotherapy (TTT) has been shown to induce heat shock protein (Hsp 70) in the optic nerve head tissue.1 The overexpression of Hsp70 has been shown to have neuroprotective effect in the chronic intraocular pressure elevation model in the rat. This study investigated the neuroprotective effect of TTT in the optic nerve crush injury model in the rat.
Methods: :
TTT was performed on the center of the optic disc in 10 eyes of 10 rats. After 24 hours, optic nerve crush injury was induced at 2 mm posterior to the eyeball using an aneurysm clip for 60 seconds. Another 10 eyes of 10 rats served as a control group (optic nerve crush injury without previous TTT). Two weeks later, retrograde labeling of retinal ganglion cells (RGCs) with dextran tetramethylrhodamine crystal was done and the density of surviving RGCs was calculated.
Results: :
In the control group, the mean density of surviving RGCs (cells / mm2) was 195.91 ± 52.91, 168.74 ± 47.96, and 141.57 ± 32.89 at 1, 2, and 3 mm from the optic disc, respectively, at 2 weeks after optic nerve crush injury. In the TTT group, the survival of RGC at 2 weeks (242.66 ± 36.96 cells / mm2) was significantly higher than that of the control group in retinal areas 1 mm from the optic disc (p=0.038, two–tailed t–test), but the differences were not significant in surviving RGCs at 2 and 3 mm from the disc.
Conclusions: :
These results demonstrate the possibility that TTT could be applied as a novel therapeutic approach to glaucoma through an enhanced induction of Hsp. Reference: 1. Park KH, et al. IOVS 2005;46(4):ARVO Abstract #1309
Keywords: neuroprotection