[Expression of immediate early gene c-fos in the lateral geniculate nucleus of rats with optic nerve injury].

OBJECTIVE

To investigate the early neuronal response to optic nerve crush in the lateral geniculate nucleus (LGN) of rats.

METHODS

Unilateral optic nerve crush injury was produced in Sprague-Dawley rats by using micro clips of 70 gram forces. The rats were sacrificed at time periods of 2 hours, 1, 3, 7 and 14 days after crush. C-fos expression was studied with a polyclonal antibody by immunohistochemistry and Western blot. Double immunolabelling of c-fos and calbindin D-28k was also studied by confocal laser scanning microscope.

RESULTS

Expression of c-fos was observed ipslaterally in the medial subdivision of ventral LGN and intermediate geniculate nucleus (IGN). The numbers of c-fos positive cells were visible at 2 h post injury and peaked at 1 d. Thereafter, the expression decreased at 3 d, 7 d and still a few was observed at 14 d. C-fos immunoreactivity was scarcely observed in the dorsal LGN and in the LGN of control rats. Expression of calbindin D-28k was mainly observed in the medial subdivision of ventral LGN and IGN. 75% approximately 83% c-fos positive cells were also calbindin D-28k immunopositive.

CONCLUSIONS

Expression of c-fos was induced in calbindin D-28k positive relay neurons in the ipslaterally medial subdivision of ventral LGN and IGN. They may play some important roles during the pathologic process of acute optic nerve injury.