In vitro effect of Y27632 on dorsal root ganglion neurons axonal regeneration in neogenetic rats with spinal cord injury

English Keywords:Spinal cord injury  Dorsal root ganglia  Axonal regeneration  Y27632  Rho-associated coiled-coil-containing protein kinase Ⅱ  Rat

English Abstract:

  【Abstract】 Objective：To explore the in vitro effect of Rho-associated coiled-coil-containing protein kinase Ⅱ（ROCK Ⅱ） inhibitor（Y27632） on dorsal root ganglion（DRG） neurons axonal growth and extension with in neogenetic rats with spinal cord injury.Method：All thoracic-lumbar DRGs harvested from new-born Sprague-Dawley（SD） rats（<5d） were cultured，purified and indentified.15 adult female SD rats were randomly divided into three groups with each group of 5 animals.5 animals were subjected to weight-drop impact inducing T9 spinal cord injury（SCI），5 in sham operation group and 5 in normal group.T8-T10 spinal cord extracts（SCEs）were harvested in each group at 7th day after spinal cord injury.The experiment was divided into 5 groups which termed as followings：DRG neurons + phosphate-bufered saline（PBS）（group A），DRG neurons + normal SCEs（group B），DRG neurons + sham operation SCEs（group C），DRG neurons + SCI SCEs（group D） and DRG neurons + SCI SCEs +（5μmol/L，10μmol/L，20μmol/L，30μmol/L，40μmol/L，50μmol/L）Y27632（group E）.The average axonal length and positive expression of tubulin βⅢ at distal end of neuronal axons were observed after 2 days′ co-culture respectively in intro.Result：There was no difference with regarding to average axonal length among group A，B and C respectively，while the axonal length in group D was significant shorter than in group A，B and C.The mean tubulin βⅢ fluorescence densities of axonal distal end in group D was significant weaker than in group A，B and C no difference existed between group A，B and C.In 5-10μmol/L Y27632 group，there were average longer axonal length and higher expression of tubulin βⅢ at axonal distal end than in group D，but less than in group A，B and C respectively.10μmol/L Y27632 group showed longer length and higher expression than 5μmol/L Y27632 group.In 20-50μmol/L Y27632 groups，average axonal length showed no difference but higher expression of tubulin βⅢ at axonal distal end existed compared with group A，B and C，which was more than 5-10μmol/L Y27632 groups and group D.There no difference among 20-50μmol/L Y27632 groups.Conclusion：The SCI SCEs inhibit DRG neurons axonal growth obviously，5~10μmol/L Y27632 could promote axon growth，while 20~50μmol/L Y27632 could promote axon growth obviously.