Project description:Gamma knife surgery (GKS) is used for treatment of various brain disorders. The effects of gamma irradiation to targeted and un-targeted regions were evaluated by monitoring gene expression changes in the unilateral irradiated (60 Gy) and contralateral un-irradiated striata in the rat. Striata of irradiated and control brains were dissected 16 h post-irradiation for analysis by rat whole genome 44K DNA oligo microarray. Results revealed 230 induced and 144 repressed genes in the irradiated striatum and 432 induced and 239 repressed genes in the un-irradiated striatum. The number of altered genes in un-irradiated striatum was more than that in irradiated striatum. Results of RT-PCR and western analyses suggested that gamma-irradiation caused cellular damage, including oxidative stress, in both striata of both hemispheres. Our present results indicate that unilateral irradiation during GKS produce bilateral effects as early as 16 h, the time-period analyzed, and these molecular changes in the un-irradiated striatum are ample proof.