| [Abstract] Objective To inestigate and discuss the mechanism of GAP-43mRNA expression in LGN(Lateral Geniculate nucleus)with Neurotrophins(BDNF and CNTF) to assist the optic nerve(ON) in repairment and regeneration after its’Hemi-Injury. To search new way for functional and effective optic nerve regeneration. Methods The cats act as the experimental object Before operation, the animals were randomly divided into 4 groups,10 cats are used as normal contrast group(N);10 cats for ON1/2 semidiameter Incision Group(ON1/2I);10 cats act as ON1/2 Incision and Injection Physiological Saline water into intraocular vitreous Group(ON1/2I+PS)；10 cats are as ON1/2 Incision, at the same intraocular vitreous Injecting Ciliary Neurotrophic Factor(CNTF) and Brain-Derived Neurotrophic Factor Group(BDNF), (ON1/2I+BF)。After the experimental cats were operated to make the models of ON semidiameter Incision (ON1/2I) and those animals were fed for four weeks, sixteen weeks and thirty-two weeks respectively under the same condition of visual environment, N, ON1/2I, ON1/2I+PSW and ON1/2I+BF were examined with Pattern and Photograph of GAP-43mRNA expression in LGN for two times(in the 4th and 8th month). Then, the results of GAP-43mRNA expression in the lamine of LGN of the normals and animal models were microscope-analysed and investigated with two pair T-test. Results of topograph analysis on GAP-43mRNAImmunocytochemistry and in situ hybridization studies: The fourth month after the optic nerve was injuried at 1/2 of diameter, ON1/2I, ON1/2I+PS group and ON1/2I+BDNF and CNTF group are compared with normal group for Integral Optic Density (IOD) and Number density (ND) of GAP-43 immunopositive neurons in lamine of LGN input from normal eye and injuried eyes by computor-topograph-analysis, there are significant difference: N/ON1/2I(P<0.001)；N/ON1/2I+PS(P<0.001)；N/ON1/2I+BF(P<0.01, P<0.05); ON1/2I+BF/ON1/2I+PS(P<0.05)；ON1/2I+BF/ON1/2I(P<0.01)。The result showed that there are GAP-43 immunopositive neurons in lamine of LGN input from normal eyes of N group and injuried eyes of (ON1/2I, ON1/2I+PSW group and ON1/2I+BDNF and CNTF group).The statistics analysis proved that IOD and ND of GAP-43 immunopositive neurons in lamine of LGN input from injuried eyes (ON1/2I and ON1/2I+PSW )group have decreased significantly. while ON1/2I+BDNF and CNTF group was compared with normal group in IOD and ND of the GAP-43 immunopositive neurons in lamine of LGN input from their eyes, there are also significant difference. The eighth month after the optic nerve was injuried at 1/2 of diameter, IOD and ND of GAP-43 immunopositive neurons in lamine of LGN input from ON1/2I and ON1/2I+PSW eyes have reduced more significantly than the fourth month after the optic nerve was injuried at 1/2 of diameter.however, IOD and ND of GAP-43 immunopositive neurons in lamine of LGN input from ON1/2I+BDNF and CNTF eyes have not reduced more significantly than the fourth month after the optic nerve was injuried at 1/2 of diameter. So, the results of GAP-43mRNA gene expression in lamine of LGN input from experimental eyes is similar to the one of GAP-43 immunocytochemistry in lamine of LGN input from experimental eyes The fourth month after the optic nerve was injuried at 1/2 of diameter. The statistics analysis proved that IOD and ND of the GAP-43 immunopositive neurons in lamine of LGN input from injuried eyes (ON1/2I and ON1/2I+PSW )group have decreased. while ON1/2I+BDNF and CNTF group was compared with normal group in IOD and ND of the GAP-43mRNA immunopositive neurons in lamine of LGN input from their eyes, there are significant difference. Conclusion 1. It is possible for ON to be assisted regeneration after the optic nerve was injuried at 1/2 in diameter by .offering a constantly artificial environment or external neurotrophic condition. Compound of BDNF and CNTF has an effective to promote regeneration of injuried optic nerve and regulate micro-environment on injuried point of optic nerve as well as supplementary affect. 2.The experimental results of Immunocyto-chemistry indicates that there are a lots of GAP-43 immunopositive neurons as will as immunopositive fibers in A,A1 and C layer of lateral geniculate nucleus. The layers of lateral geniculate nucleus input from (ON1/2I) and (ON1/2I+PSW) injuried eyes show up the expression of GAP-43 to weaken or lose. GAP-43 immunopositive neurons and fibers decrease. Statistic results show that the layer of LGN input from (ON1/2I+BDNF and CNTF) injuried eyes is compared with The layer of LGN input from (ON1/2I and ON1/2I+PSW) eyes with Paired-samplesT-test to have observed the stronger and more on expriession of GAP-43 protein and GAP-43 immunopositive neurons as well as immunopositve fibers than that of LGN input from (ON1/2I and ON1/2I+PSW) eyes, which proved progressively the results on investigation of PVEP. The results show that compound liquefacient of BDNF and CNTF can promote regeneration of injuried optic nerve. 3. Observation on the experimental results of in situ hybridization proved that compound liquefacient of BDNF and CNTF can promote regeneration of 1/2 injuried optic nerve and possess significant effect against injury. Positive signals of GAP-43mRNA expression in layer of LGN input from (ON1/2I+BDNF and CNTF) injuried eyes is compared with Positive signals of GAP-43mRNA expression in layer of lateral geniculate nucleus input from (ON1/2I and ON1/2I+PSW) eyes with Paired-samplesT-test to have observed the stronger and more on expriession of GAP-43mRNA. However, We also wonder whether compound liquefacient of BDNF and CNTF possesses synthetic regulation effect for micro-environment on injury and regeneration or not ? Further studies are required to answer these questions.
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