Neuroprotective effect of transpupillary thermotherapy in the optic nerve crush model of the rat

Purpose Transpupillary thermotherapy (TTT) has been shown to induce heat shock protein (Hsp) 72 in optic nerve head tissue. The neuroprotective effect of TTT was investigated in an optic nerve crush rat model. Methods TTT was performed onto the optic nerve head in the right eye of subject rats. After 24 h, an optic nerve crush injury using an aneurysm clip was performed at 2mm from the optic nerve head for 60s. At 7 and 14 days later, retrograde labelling of retinal ganglion cells (RGCs) with DTMR crystal was carried out and the density of the surviving RGCs was evaluated. Immunohistochemical staining was performed to confirm the expression of Hsp72. Results At 7 days after optic nerve crush injury, the mean density of surviving RGCs was higher in TTT group (372.7 +/- 149.8 per mm 2) than in optic nerve crush group (252.9 +/- 96.7 per mm 2) with borderline significance. In the retinal areas at 1 mm from the optic nerve head, a significant increase in surviving RGCs from TTT treated eyes was observed at both 7 and 14 days after optic nerve crush injury. However, no significant differences in surviving RGCs were demonstrated 2 and 3mm from the optic nerve head. Conclusions These results demonstrate that TTTaimed onto the optic nerve head showed a neuroprotective effect.Sarikcioglu L, 2007, EXP EYE RES, V84, P373, DOI 10.1016/j.exer.2006.10.013Kim JM, 2006, INVEST OPHTH VIS SCI, V47, P4888, DOI 10.1167/iovs.05-1328Mochizuki Y, 2004, RETINA-J RET VIT DIS, V24, P981Ming Y, 2004, INVEST OPHTH VIS SCI, V45, P1969, DOI 10.1167/iovs.03-1329Abramson DH, 2004, OPHTHALMOLOGY, V111, P984, DOI 10.1016/j.ophtha.2003.08.035Tidwell JL, 2004, CELL STRESS CHAPERON, V9, P88Hou B, 2004, INVEST OPHTH VIS SCI, V45, P662, DOI 10.1167/iovs.03-0281Tsuchiya D, 2003, NEUROSURGERY, V53, P1179, DOI 10.1227/01.NEU.0000090341.38659.CFThach AB, 2003, ARCH OPHTHALMOL-CHIC, V121, P817Ishii Y, 2003, INVEST OPHTH VIS SCI, V44, P1982, DOI 10.1167/iovs.02-0912Sakai M, 2003, JPN J OPHTHALMOL, V47, P42Sun WZ, 2002, VISUAL NEUROSCI, V19, P483, DOI 10.1017/S0952523802194107Kalmar B, 2002, EXP NEUROL, V176, P87, DOI 10.1006/exnr.2002.7945Journee-de Korver JG, 2002, PROG RETIN EYE RES, V21, P303Park KH, 2001, INVEST OPHTH VIS SCI, V42, P1522Mainster MA, 2000, OPHTHALMIC SURG LAS, V31, P359Li CY, 2000, J BIOL CHEM, V275, P25665Dean DO, 1999, INVEST OPHTH VIS SCI, V40, P2952Caprioli J, 1996, INVEST OPHTH VIS SCI, V37, P2376Houenou LJ, 1996, CELL STRESS CHAPERON, V1, P161Hartl FU, 1996, NATURE, V381, P571Kaneko T, 1996, J NEUROSCI METH, V65, P157FRITZSCH B, 1993, J NEUROSCI METH, V50, P95MAILHOS C, 1993, NEUROSCIENCE, V55, P621CHOPP M, 1989, NEUROLOGY, V39, P1396