Effect of epigalocatechin gallate on neuronal loss and apoptosis after spinal cord injury in rats

Objectives: To evaluate the effec of epigallocatechin gallate(EGCG) on temporal and spatial profiles of neuronal loss and appoptosis following a contusion spinal cord injury(SCI) in rats.

Methods: SD rats were randomly divided into three groups(25 rats each): sham-operated group, SCI group (normal saline solution intraperitoneal injection, immediately and 1 hour after SCI), and EGCG treatment groups (50 mg/kg, intraperitoneal injection, immediately and 1 hour after SCI). SCI model was made by aneurism clips methods. The rats were sacrificed at 6,12,24 hours,3 and 7 days; 5 rats at each time point after injury. The profiles were evaluated by counting the cresyl violet-stained surviving neurons in section 0-4.50 mm and the total number of TUNEL-positive neurons in sections 0-4.55 mm and Caspase-3 positive neurons in sections 0-4.60 mm rostral and caudal from the epicenter. RESULT: We demonstrated that neurons continue to disappear over 1 week postinjury and that neuronal loss shifts to areas longer distances from the epicenter over time. TUNEL-positive and Caspase-3 positive neuron in gray matter appeared after 6 hour, gradually increased to a peak level after 72 hour, and declined by 1 week postinjury respectively. The neuronal loss and apoptosis were partially prevented by a EGCG. We demonstrated that EGCG significantly reduced neuronal death in the sections 1.50-3.50 mm rostral and 2.00-3.00 mm caudal from the epicenter compared with that in the vehicle-treated group, suggesting EGCG is more effective in the sections rostral than in those caudal to the epicenter. EGCG significantly reduced the number of TUNEL-positive neurons in the sections 1.05-3.05 mm rostral and 1.55-3.05 mm caudal from the epicenter, and Caspase-3 positive neurons in the sections 1.60-3.10 mm rostral and 1.60-2.60 mm caudal from the epicenter respectively.

Conclusions: Our profiles provide a database for pharmacological intervention, and our resaults on EGCG treatment support an important role for anti-apoptosis therapy in SCI.