Effect of the running and balance exercise on mechanoreceptor and prepheral nerve in the aged rats pads

神经营养因子是一类可溶配体，可促进周围和中枢神经元的存活和分化。最近的研究表明，跑步机运动可提高大鼠脊髓和肌肉中神经营养因子的表达水平。本研究的目的是探讨运动是否能提高肌垫神经营养因子的表达水平。实验一：选取年龄为2岁的Wistar雄性老龄大鼠，随机分为两组：不运动大鼠和在跑步机上运动大鼠。动物在跑步机上进行四足运动，直到它们能够以11-13m/min的速度在皮带上保持前进姿势。在运动组和非运动组中，pad中检测到NT3、NT4、TrkB、TrkC和P75mRNA。运动组TrkC和p75mrnin的表达明显低于非运动组。运动组与非运动组相比，NT3、NT4、Trk B mrna的表达无显著性差异。实验2老龄Wistar雄性大鼠（2岁）和成年雄性大鼠（10周龄）随机分为成年运动组、成年不运动组、老年不运动组和老年不运动组。动物在移动平台上训练4周（每周5天）。RT-PCR检测NT3、NT4及其受体TrkB、TrkC的mrna表达。老年人运动组NT3和TrkC表达水平高于成年组。运动使老年大鼠的NT4水平升高，与成年大鼠相比，运动大鼠的TrkB水平较高。皮肤产生的神经营养因子通过轴突逆行转运传递到神经素相关的神经营养因子。本研究提示神经营养因子trk信号的衰减可能与衰老过程中感觉缺陷的严重程度有关。

Neurotrophins are a family of soluble ligands that promote the survival and differentiation of the peripheral and central neurons. Recent research indicated that the treadmill exercise enhanced the expression level of neurotrophin in the spinal cord and the muscle in rats. The objective of this study was to investigate whether exercises enhance the expression level of neurotrophin in pads.Experiment 1Aged Wistar male rats, 2 years old, were randomly assigned to one of two groups: non-exercised rats and treadmill exercised rats. Animals performed quadrupedal locomotion on a treadmill until they could maintain a forward position on the belt moving at 11-13m/min Locomotor training was carried out for 4 weeks (5 days a week).In both exercised groups and non-exercised groups, NT3, NT4, TrkB, TrkC, and P75mRNA were detected in the pads.The expression TrkC and P75mRNAin the exercised group were significantly less than of non-exercised group.The expression NT3, NT4, Trk B mRNAin the exercised group were not significantly than ofnon-exercised group.Experiment 2Aged Wistar male rats (2 years old) and adult male rats (10 weeks old) were randomly assigned groups: adult with exercise, adult without exercise, aged with exercise, and aged without exercise. Animals were trained on a moving platform or 4 weeks (5 days a week).. The mRNAs for NT3, NT4, their receptors TrkB, TrkC were measured by quantitative RT-PCR. NT3 and TrkC levels of expression in aged group with exercise were more higher than that of the adult groups. The exercise increased the NT4 level TrkB levels of aged rats with excercise was high compared with adult rats with exerciseThe skin produced neurotrophins which are conveyed via retrograde axonal transport to the nerve element related neurotrophins. Athis study suggests that The attenuation of neurotrophin-Trk signaling may correlate with severity of sensory deficits in senescence.