Abstract: Objective To observe the effect of astragalus polysaccharide on motor function and pathology after spinal cord injury in rats. Methods Seventy adult Sprague-Dawley rats were selected as normal group (n=10), injury group (n=30) and treatment group (n=30), and the injury group and the treatment group were divided into 7 days, 14 days, 28 days subgroups. The injury group and the treatment group were modeled with Allen's mode at T10 (10 g×25 mm). The treatment group was injected with astragalus polysaccharide 10 mg/kg per day after injury. They were rated with Basso-Beattie-Bresnahan (BBB) scores 7 days, 14 days and 28 days after injury, while the morphology was observed with HE staining, Nylon body was observed with Nissl staining, and myelin sheath was observed with eriochrome cyanine staining. Results The BBB score was significantly higher in the treatment group than in the injury group at each time point (P<0.05). There was a large number of necrotic tissue in the injured cords and cystic cavity began to form 7 and 14 days after injury. Cystic cavity formed basically and surrounded with dense scar 28 days after injury. The necrosis and cystic cavity alleviated in the treatment group at each time point. Demyelination and myelin sheaths loose were found 7 days after injury, and aggravated with the time. There was a cystic cavity in trauma center 28 days after injury. The demyelination and myelin sheaths loose relieved at each time point in the treatment group. Nissl bodies began to coalesce 7 days after injury, and aggravated 14 days after injury, coalesced completely 28 days after injury. Nissl body coalesced alleviatively in the treatment group at each time point. Conclusion Astragalus polysaccharide may reduce the damage and promote the recovery of motor function after spinal cord injury in rats.

Key words: spinal cord injury, astragalus polysaccharide, motor function, pathology, rats