In vitro effect of TDZD-8 on DRG neurons axonal regeneration in rats

English Keywords:Spina cord injury  Dorsal root ganglias  Axonal regeneration  TDZD-8  Glycogen synthase kinase 3β inhibitor

English Abstract:

  【Abstract】 Objective：To explore the in vitro effect of TDZD-8（inhibitor of GSK-3β） on DRG neurons axonal regeneration in rats.Method：All thoracic-lumbar DRGs of newborn SD rats（<5d） were harvested under the stereopsis microstat，and then DRG neurons were cultured，purified and indentified.15 adult female SD rats were randomly divided into three groups and 5 were subjected to weight-drop impact inducing complete paraplegia，5 were in sham group and 5 in normal group respectively.The T8-T10 spinal cord extracts（SCEs） were harvested from 3 different groups respectively at the 7th day after operation.5 groups were assigned as follows，group A was DRG neurons + PBS，group B was DRG neurons + normal SCE，group C was DRG neurons + sham operation SCE，group D was DRG neurons + complete paraplegia SCE and group E was DRG neurons + complete paralysis SCE + TDZD-8.The average axonal length and positive expression of Tubulin βⅢ at distal end of neuronal axons were observed after 2 days co-culture.Result：There was no difference in average axonal length among group A，B and C respectively，while the axonal length in group D was significant shorter than that in group A，B and C respectively.The mean Tubulin βⅢ fluorescence density of axonal distal end in group D was significant weaker than that in group A，B and C respectively and no difference was noted between group A，B and C.In 0.5-3μM TDZD-8 treatment groups，there were not only longer in average axonal length and higher in expression of Tubulin βⅢ at axonal distal end than in those in group A，B and C respectively，but significant longer than that in group D.In 5-25μM TDZD-8 treatment groups，the average axonal length was shorter than that in group A，B and C，while the expression of Tubulin βⅢ at axonal distal end was significant higher than that in other groups respectively（P＜0.01）.Conclusion：The complete paraplegia SCEs inhibit DRG neurons axonal growth obviously，which induce axonal retraction and growth cone collapse.Low dose of TDZD-8 can promote axon growth while high dose can inhibit axon growth obviously.TDZD-8 can enhance the expression of Tubulin βⅢ at neuronal axon shaft and growth cone，especially in high dose.