Protective Effect Of Intermittent Standing Physical Therapy On Dorsal Root Ganglion In Simulated Weightlessness Rats

Objective: To study the changes of intermittent standing on dorsal root ganglia(DRG),glial cell line-derived neurotrophicfactor(GDNF),nissl bodies,myelin,mitocho ndrias in simulated weightlessness rats to find some protection theories for the p revention and treatment of dorsal root ganglion injury.Methods: Select 30 of 10-week-old male SD rats. The average weight was (180±20)g.They were randomly divided into simultaneous control (CON), eight-week tail-suspension (SUS) and tail-suspension plus daily 1h standing (STD).The STDg roup rats stand 1 h daily in the horizontal position of the tubular cage without t urn around.After 8 weeks,both side L5-DRG were taken out.The structure of mye lin and mitochondrial were observed in electron microscopy. GDNF and GFAPprot ein expressions was measured by Westernblot and GDNF mRNA expressionwas measured by RT-PCR.Detected the contents of mitochondrial ATP and ATPase.Results: Compared with SUS, STD group DRG cells have no obvious swelling and gap widened.Mitochondrias are slightly swollen and mitochondrial cristas are present.The thickness of SUS is 55% lower than CON thickness, and 49% lower than STD.The expression of GDNF protein in SUS was 48% lower than that in CON and 68% lower than that in STD.The expression of SUS GFAP protein in the dorsal root ganglion was 71% higher than that in CON, and the expression of SUS GFAP protein was 33% higher than that in STD.The expression of GDNF mRNA in SUS dorsal root ganglion was 17%lower than CON,and 34% lower than STD.The content of ATP in SUS was 60% lower than CON,and 36% lower than STD.The content of ATPase in SUS was 56% lower than CON,and 44% lower than STD.Compared with three groups,SUS group have significant statistical difference with the other two groups(P<0.05).The observed indicators of STD group have no significant statistical difference with the CON group.(P > 0.05).Conclusions:After 8 weeks,the DRG cells,the structure of Nissl body,myelin,mitoc hondrial and related proteins were damaged.And intermittent standing could reduc e the early injury of DRG.The results of this experiment can prove guides and medical protection measures to protect astronaut from low back pain after space flight.