Schwann cells-alginic acid sodium hydrogel transplantation for repair of spinal cord injury in rats / 中国组织工程研究

ABSTRACT

OBJECTIVE:To investigate the influences of Schwann cells-alginic acid sodium hydrogel transplantation on cellular apoptosis,Bcl-2 expression,and lower limb locomotor function in a rat model of spinal cord injury.METHODS:SD rats of clean grade were randomly divided into 4 groupsnormal control,simple injury,Schwann cells,and Schwann cells-alginic acid sodium hydrogel.Spinal cord transaction model was established in the latter 3 groups.Gelatin sponge blocks containing Schwann cells suspension were transplanted into the Schwann cells group.Schwann cells-alginic acid sodium hydrogel was transplanted into Schwann cells-alginic acid sodium hydrogel group.No treatments were performed in the normal control and simple injury groups.At 12 hours,1,3,7,and 21 days after surgery,animals were assessed using Basso,Beattie and Bresnahan (BBB) locomotor rating scale and were sacrificed.The spinal cord-transected segments were taken to prepare paraffin sections for TUNEL and Bcl-2 staining to quantitate apoptotic cells and Bcl-2 cells in the injured spinal cord and to investigate their distributions.RESULTS:A small number of slightly stained Bcl-2 positive cells were observed in the normal control group.In the simple injury group,Bcl-2 immunoreactive cells peaked at 3 days after surgery,and the expression level was close to normal level at 14 days.Following Schwann cells-alginic acid sodium hydrogel transplantation,Bcl-2 immunoreactive cells in the spinal cord-transected segments were significantly increased till 7 days (P＜0.05) and remained this level for more than 14 days.In the simple injury group,apoptotic cells were most as compared with the remaining 3 groups,and peaked at 1 and 7 days following spinal cord injury,and they were mostly distributed in the white matter.BBB scores were significantly higher in the Schwann cells-alginic acid sodium hydrogel transplantation group than in the simple injury and Schwann cells groups (P＜0.05).CONCLUSION:Schwann cells-alginic acid sodium hydrogel transplantation could inhibit cellular apoptosis and enhance Bcl-2 expression in the spinal cord-transected segments,and thereby promote the recovery of locomotor function after spinal cord injury but did not reach normal levels.