Abstract: Objective To observe the effect of grape seed proanthocyanidin extract (GSPE) on growth associated protein-43 (GAP-43) through extracellular signal regulated kinase 1/2 (ERK1/2) pathway in rats with brain radiation injury. Methods 72 3- month male Sprague-Dawley rats were divided into control group (n=18), model group (n=18), high dose GSPE group (n=18) and low dose GSPE group (n=18). The brain radiation injury models were established by linear accelerator irradiation with 22 Gy. The learning ability was assessed with shuttle box. The morphological changes of neurons in hippocampus were observed with HE staining; the expression of GAP-43 was detected by RT- PCR; and the expression of phosphorylated ERK1/2 was detected by Western blotting. Results Compared with the model group, the active avoidance reaction rate in the shuttle box test increased and the passive avoidance latency shortened in GSPE groups (P< 0.001); the nerve cell morphological injury reduced and the expression of GAP-43 mRNA and phosphorylated ERK1/2 increased in the GSPE groups (P<0.001), especially in the high dose GSPE group (P<0.001). The GAP-43 mRNA level positively correlated with phosphorylated ERK1/2 level in the model group (r=0.764, P<0.001), the low dose GSPE group (r=0.814, P<0.001) and the high dose GSPE group (r= 0.822, P<0.001). Conclusion GSPE could promote the expression of GAP-43 through ERK1/2 pathway in rats, and prevent the brain from radiation injury.

Key words: brain radiation injury, learning, growth associated protein-43, extracellular signal regulated kinase 1/2, rats