The Expressions Of GAP-43 MRNA And HuD MRNA On The Retina During Optic Nerve Regeneration In Rats

Purpose:The sciatic nerve graft could promote the injuried opric nerve regeneration, butthe mechanism was not clear. To assess this, the growth associated protein-43(GAP-43) message RNA (mRNA) and HuD mRNA on the retina were analyzed in theSprague-Dawley (SD) rat retina during optic nerve regeneration.Methods:After the optic nerve was exposed intraorbitally and transected just behind 5mmwith the eye then the autologous segment of sciatic nerve (SN group) or optic nerve(ON group) was sutured to the ocular ON stump, the remainder of the graft was laidover the cranium and covered by scalp. The normal group(N group) had no deal. Theexpressions of GAP-43 mRNA and HuD mRNA on the retina were observed byReverse Transcription-Polymerase (RT-PCR) analysis after transection, 3 days,7daysand 14days later.Results:1. A minimum expression of GAP-43 mRNA was found on normal retina. After the optic nerve was transected and sutured with the autologous segment of optic nerve, the expression was significantly higher than that in the normal group(P﹤ 0.05). The expression increased, about 24%,84% and 34% after 3 days, 7daysand 14 days, which were significantly higher than that in the normal retina(P﹤ 0.05).2. After the optic nerve was transected and sutured with the autologous segment of sciatic nerve, the expression of GAP-43 mRNA was significantly higher than that in the normal group and that in the ON(P﹤0.05). The expression increased more obvious, about 51%,137% and 59% after 3 days, 7days and 14 days, which were significantly higher than that in the normal retina and that in the contemporaneous rat in the ON(P﹤0.05).3. A minimum expression of HuD mRNA was found on normal retina. After the optic nerve was transected and sutured with the autologous segment of optic nerve, the expression was significantly higher than that in the normal group(P﹤ 0.05). The level of expression increased, about 15% and 4.4% after 3 days, 7days but decreased 8% after 14 days. The expression in the 3d was significantly higher than that in the normal retina(P﹤0.05).4. After the optic nerve was transected and sutured with the autologous segment of sciatic nerve, the expression of HuD mRNA was significantly higher than that in the normal group and that in the ON(P﹤0.05). The level of expression increased more obvious, about 26.3%,39% and 5.3% after 3 days, 7days and 14 days . The expression in the 3d ,7d was significantly higher than that in the normal retina(P ﹤0.05)and the expression in every time was significantly higher than that in the contemporaneous rat in the ON(P﹤0.05).Conclusion:1. GAP-43 and HuD were concerned with the regeneration of optic nerve.2. After optic nerve was transected, GAP-43 was little in the RGCs , which lead tothe "abortive regeneration"of optic nerve.3. .Afte autologous segment of sciatic nerve was sutured to the transected optic nerve, the graft could promote RGCs product GAP-43 which spured optic nerve to regenerate.4. After optic nerve was transected, the initial HuD in RGCs could promote GAP-43 to express. Autologous segment of sciatic nerve could augment the process which stimutated optic nerve to regenerate.5. After autologous segment of sciatic nerve was transplanted HuD expressed in 7d would contribute other process that needed investigation.