Survival and number of olfactory ensheathing cells transplanted in contused spinal cord of rats

Objective: To observe the survival and the number of olfactory ensheathing cells (OECs) transplanted in the contused spinal cord, so as to provide a basis for further studying the biological action of OECs.Methods: The rat spinal cords were contused with NYU-impactor Ⅱ at T10 level by dropping a 10 g rod from a height of 25 mm. At the 1st week after injury, OECs isolated freshly from green fluorecense protein (GFP) of the rats were transplanted into the spinal cord at injured site and other two sites 1 mm apart from the caudal and rostral ends with the OECs number of 30000/μl×3 =90000. The survival and the number of OECs were qualitatively and semi-quantitatively observed under the fluorescense microscope from 1 week to 13 weeks after transplantation. The motor function of the cord was evaluated with BBB score.Results: GFP-OECs could survive at least for 13 weeks within the contused spinal cord. Their arrangement was from tight to loose and their number was decreased from 1 week to 13 weeks after injury. The average number of GFP-OECs was 536 at the 1st week, which was less than 1% of the number as compared with original transplantation. After then, the number of GFP-OECs was continually decreased,but the most obvious decrease was found during 1 week to 2 weeks. The extent of decrease at other time points was relatively mild. In contrast to the cell number, motor function of the cord was gradually recovered after transplantation.Conclusions: The survival and the number of GFPOECs are different between the animals and are affected by the pathological reaction of the host cord. Also it is related to the motor function recovery of the contused cord.