Study of gene therapy on hypoalgesia in sensory neuropathy using neurotrophic factors

VEGF 120不与神经纤毛蛋白-1（nrp-1）结合，但与胎肝激酶（flk-1）和fms样酪氨酸激酶（flt-1）受体结合，而VEGF 164与这些受体结合。为了检测VEGF 120过表达对感觉缺陷的影响，将VEGF 120质粒注射到具有痛觉减退的糖尿病小鼠的双侧TA肌肉中，随后进行电穿孔。在电基因转移后，双侧测量后爪背上的伤害感受阈值。通过电穿孔转移VEGF 120基因并没有显著降低伤害性阈值。为了证实VEGF的过度表达，我们通过ELISA电穿孔法在注射VEGF 120质粒后2周测量了糖尿病小鼠TA肌肉中的VEGF水平。胎盘生长因子2（P1 GF 2）在体外通过nrp-1受体对背根神经节（DRG）神经元具有神经营养活性。为了检查P1 GF 2治疗糖尿病神经病变的效率，通过电穿孔进行肌内P1 GF 2基因转移以治疗糖尿病小鼠的感觉神经病变。P1 GF 2在具有痛觉减退的糖尿病小鼠的TA肌肉中过表达，使用P1 GF 2质粒注射与电穿孔。在将电基因转移到双侧TA肌肉中两周后，在所有治疗的小鼠中升高的伤害性阈值显著降低。在P1 GF 2质粒电穿孔小鼠中，未发现坐骨神经中神经内膜血管的数量增加。综上所述，这些发现表明VEGF 164和P1 GF 2电基因治疗通过DRG神经元中的nrp-1受体显著恢复糖尿病小鼠中的感觉缺陷，即痛觉减退。

VEGF120 does not bind to neuropilin-1 (nrp-1) but binds to fetal liver kinase (flk-1) and fms-like tyrosine kinase (flt-1) receptors, while VEGF164 binds these receptors. To examine the effect of VEGF120 overexpression on sensory deficits, VEGF120 plasmid was injected into bilateral TA muscles of diabetic mice with hypoalgesia followed by electroporation. After electro-gene transfer, the nociceptive threshold on the dorsum of the hindpaw was measured bilaterally. VEGF120 gene transfer by electroporation did not significantly reduce the nociceptive threshold. To confirm the overexpression of VEGF, we measured VEGF levels in TA muscles of diabetic mice at 2 weeks after VEGF120 plasmid injection with electroporation by ELISA. There was a significant increase in the VEGF level in these samples compared with samples from diabetic mice at 2 weeks after control plasmid injection with electroporation.Placental growth factor2 (P1GF2) has neurotrophic activity in dorsal root ganglion (DRG) neurons through nrp-1 receptor in vitro. To examine the efficiency of P1GF2 therapy for diabetic neuropathy, intramuscular P1GF2 gene transfer by electroporation was performed to treat sensory neuropathy in diabetic mice. P1GF2 was overexpressed in the TA muscles of diabetic mice with hypoalgesia, using a P1GF2 plasmid injection with electroporation. Two weeks after electro-gene transfer into the bilateral TA muscles, the elevated nociceptive threshold was significantly decreased in all treated mice. No increase in the number of endoneurial vessels in the sciatic nerve was found in the P1GF2 plasmid-electroporated mice. Taken together, these findings suggest that VEGF164 and P1GF2 electro-gene therapy significantly recovered the sensory deficits, i.e. hypoalgesia, in the diabetic mice through nrp-1 receptor in DRG neurons.