Neuroprotection Of The PTEN Inhibitor On Spinal Cord Injury In Rats

Part1Expression of PTEN/mTOR signaling pathways associated protein in the spinal cord of rats at different stages of developmentObjective:To investigate the expression of PTEN/mTOR signaling pathways associated protein in the spinal cord of rats at different stages of development.Methods:Rats were randomized into four groups,E15、P0、P7、P56.The expression of PTEN/mTOR signaling pathways associated protein in the spinal cord of rats at different stages of development was detected by the immunohistochemistry and Western blotting.Results:For PTEN, the band of E15was much weaker than the others.The expression of PTEN increased at PO, which reached its peak at P7and decreased to a quantitative level at adult.The expression of Akt seemed equal to each other. Meanwhile in the spinal cord of rats at P0, P7and P56, neurons were found to be abundant of PTEN expression, and PTEN was detected both in the nucleus and cytoplasm.The expression of p-PTEN decreased after birth.Similarly, p-S6were also gradually reduced after birth.Conclusion:PTEN/mTOR signaling pathway associated protein expression changes in the spinal cord of rats during development.It plays an important role that PTEN/mTOR signaling pathway may maintain the spinal cord anterior horn neurons in the normal growth. Part2Expression of PTEN/mTOR signaling pathways associated protein in the experimental spinal cord injury in ratsObjective:To investigate the expression of PTEN/mTOR signaling pathways associated protein in the development of experimental spinal cord injury,determine the efect of the PTEN/mTOR signal pathways on the development of experimental spinal cord injury.Methods:Rats were randomized into two groups,the sham-operated group and the injuried group,modified Allen’s method was used to make actue spianl cord injury. Rats were sacrificed at1d、3d after injury.The expression of PTEN/mTOR signaling pathways associated protein in the experimental spinal cord injury was detected by the immunohistochemistry and Western blotting.Results:Compared to normal tissues,we can find that the expression of PTEN decreased at3d after spinal cord injury,while p-S6significantly increased at3d.The expression of PTEN decreased3d after spinal cord injury in spinal cord anterior horn neurons.Conclusion:The expression of PTEN in experimental spinal cord injury was decreased,which opposited downstream molecules p-S6.It suggested that the PI3K/PTEN/AKT/mTOR signaling pathways could play an important role in the process of development of experimental spinal cord injury and PTEN may be a therapeutic target of spinal cord injury. Part3Effect of PTEN inhibitor on cell apoptosis following spinal cord iniury in ratsObjective:To investigate the effect of PTEN inhibitor on cell apoptosis after spinal cord injury in rats.Methods:The rats were divided into three groups including sham group, control group(injury without treatment),cured group(pre-injury with PTEN inhibitor(bpv(pic)) ip), modified Allen’s method was used to make actue spianl cord injury.Rats were sacrificed at1d and3d after spinal cord injury.The samples were examined with Terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL).The neurofuntion of spinal cord was measured by BBB score.Results:The apoptosis cells positive for TUNEL were detectable in control and cured groups.In the cured group,the number of apoptotic cells were decreased and the neurofunction of the spinal cord improved as compared with those in the control group(P<0.05).Conclusion:PTEN inhibitor can reduce the numbers of apoptotic cells and promote the nerve function recovery after spinal cord injury. Part4Endogenous stem cell proliferation induced by PTEN inhibitor after spinal cord injury in ratsObjective:we investigated the efficacy of PTEN inhibitor bpv(pic) in promotion of the proliferation and differentiation of endogenous neural stem cells/progenitor cells after spinal cord injury in rats.Methods:The rats were divided into three groups including sham group, control group(injury without treatment),cured group(pre-injury with PTEN inhibitor(bpv(pic)) ip), modified Allen’s method was used to make actue spianl cord injury.Rats were sacrificed at1d and3d after spinal cord injury. To label the activated and proliferating endogenous neural stem cells/progenitor cells, animals received one intraperitoneal injection of BrdU at50mg/kg per day.The tissue was analyzed using immunohistochemical detection to study the response of endogenous neural stem cells/progenitor cells.Results:BrdU-positive cells were detected in the spinal cord section in the control group and cured group.Compared to the control group, the number of BrdU positive cells were increased(P<0.05)after spinal cord injury, there were difference between Id and3d groups.Conclusion:PTEN inhibitor bpv(pic) can increases the population of endogenous neural stem cells after spinal cord injury in adult rats.