| ObjectiveTo explore the effect of exogenous basic fibroblast growth factor (bFGF) on calcitonin gene-related peptide expression and the morphology change in the local of the injured sciatic nerve, the dorsal root ganglion (DRG),the horn and the motor neuron of the anterior of the spinal cord. In order to provide the morphology basis of the molacular mechanism of the regeneration after the peripherial nerve injury and the new theory evidence of the treatment of the peripherial nerve injury in clinical.Method78 male Wistar rats were divided into 3 groups randomly the normal group,the positive control group (unilateral sciatic nerve injury in rat sciatic nerve injury model) and the bFGF group (the unilateral sciatic nerve injury and use the bFGF at the local of the sciatic nerve and inject the bFGF in gastrocnemius of the surgery side once of two days). Rats survived for 1d,3d,7d,14d,21d and28d after sciatic nerve crushed. Perfusioned and fixed at each time point, taken L4-6 spinal cord segment and the corresponding dorsal toot ganglia (L4-6) as well as the local part of the injuryed sciatic nerve, the changes of fibers and neurons of these places and the integral optical density value of CGRP and the average diameter of the anterior (L4-6) motor neuron were detected by immunofluores-cence and immunohistochemical method and Nissl method and image analysis.Result1. the effect of bFGF on the motor neuron of the anterior horn(L4-6) after sciatic nerve injury (1) Nissl staining There were some swelling motor neurons in the anterolateral of the anterior horn(L4-6) in the positive control group, perinuclear Nissl body began to dissolve and showed a clear shift of the nucleus, vacuolation can be seen in the cytoplasm, at the 2Id Nissl body regenerated in the majority of the motor neurons and stained darker and close to the normal at the 28d. bFGF can promote the recovery of the dissolution of Nissl body. The motor neurons in the anterolateral part of the anterior horn (L4-6) swelled in the bFGF group, the Nissl body dissolved and disappeared but not as good as the positive control group and did not see a clear nuclear translocation; the 14d after the surgery, a large number of Nissl body regenerated so that the cells stained darker; the morphology and average diameter of the anterolateral motor neurons closed to the normal at the 21d, the contralateral motor neurons of the L4-6 anterior horn no significantly change.(2) the expression of CGRP at the spinal forefoot(L4-6) There were some CGRP-positive motor neurons can be seen within the spinal cord forefoot (L4-6)of normal animals, the immune reaction product was granular or homogeneous-like distributed in the cytoplasm, the nucleus no marked, mainly seen in the anterior lateral of the anterior horn(L4-6). The expression of CGRP in the anterolateral motor neuron of the positive control group was significantly higher than the normal group after the 1d, peaked at 7d and then slowly declined to near normal at the 21d. bFGF can promote the synthesis of CGRP in the motor neuron of anterior horn(L4-6) after the sciatic nerve injury. There were some CGRP-positive motor neurons after the 1d in the bFGF group and they stained darker; then the number of the CGRP-positive cell was increased and the staining darker; these cells were stained significantly shallow at the 14d, to the 28d near normal.2. the effect of bFGF on spinal dorsal horn(L4-6) CGRP-positive fibers after sciatic nerve injury The CGRP-positive fibers at the spinal dorsal horn were mainly located in the laminaⅠandⅡ, and also found in laminaⅢandⅣand the Lissauer's tract, there were some CGRP-positive fibers projected from the laminaⅠandⅡto laminaⅢandⅣ. The density of CGRP-positive fibers in the surgery side of the positive control group decreased significantly compared with the normal group, the fibers were mainly seen in the laminaⅠandⅡ; the density of the fibers to a minimum at the 7d and only seen in the laminaⅠandⅡ; followed the CGRP-positive fibers increased but not yet reached the normal level at the 28d. bFGF can promote the recovery of CGRP-positive fibers in spinal dorsal horn (L4-6) after sciatic nerve injury. The area occupied by CGRP-positive fibers in the lamina I and II of the bFGF group significantly reduced compared with the normal group and the staining had also declined; the CGRP-positive fibers found only in the lamina I and II and the density decreased to a minimum at the 7d; the positive fibers increased significantly at the 14d and there were a large number of positive fibers in the posterior gray commissure; the positive fibers further increased at the 21d and the staining brighter at the 28d.3. the effect of bFGF on the sensory neurons of the DRG(L4-6) after sciatic nerve injury (1)Nissl staining Nissl bodies in some of the sensory neurons dissolved and disappeared in the positive control group and DRG(L4-6) neurons swelled, and then Nissl body almost did not see in some of DRG (L4-6) neurons; some DRG(L4-6) neuron stained dark blue at the 14d; the number of DRG cells had not yet reached normal level at the 28d. bFGF can promote the recovery of dissoloved Nissl body in small and medium neurons of DRG(L4-6) after scitic nerve injury. The Nissl body also dissolved and disappeared in the DRG neurons of the bFGF group; the number of small and medium DRG neurons increased significantly compared with the positive control group and the cells stained deeper at 14d; the number closed to the normal level at the 21d, but no effect on large neurons of DRG(L4-6).(2) CGRP expression within the DRG(L4-6) A large number of small and medium DRG cells were CGRP-positive neurons in the normal anminals, but also seen some large sensory neurons showed CGRP-positive, CGRP granular evenly distributed in the cytoplasm, the nucleus no mark, and some CGRP-positive nerve fibers can also be found.The synthesis of CGRP in DRG(L4-6) reduced after sciatic nerve injury. The integral optical density of small and medium CGRP-positive neurons in the positive control group was significantly lower than the normal group at the 1d (P<0.05), and reduced to a minimum at the 7d, later began to increase, but still significantly lower than he normal group at the 28d. The number of the large CGRP-positive neurons was significantly lower than the normal group and no obvious change during the whole experiment. bFGF can promote the synthesis of CGRP in DRG(L4-6), the integral optical density of CGRP in the small and medium cells of the bFGF group was significantly lower than the normal group at the 1d (P<0.05), significantly higher than the positive control group but obvious lower than the normal group at the 7d, in turn the expression of CGRP increased, closed to the normal group at the 21d and still significantly higher than the positive control group (P<0.05). The number of CGRP and the integral optical density value of CGRP in the large neurons was significantly lower than the normal group during the entire experimental process and no significant change compared with the positive control group.4. the impact of bFGF on CGRP-positive fibers at the injury part of after sciatic nerve injury The CGRP-positive fibers increased in the injury part of sciatic nerve, there was no or only seen a small amount of CGRP-positive fibers in the normal sciatic nerve, under the cricumstance of the axon fractured and the nerve membrane maintained completely, no CGRP-positive fibers can be found at the injury part of the nerve at the 1d of the positive control group, a large number of CGRP-positive fibers were found in the injury part at the 3d, the positive fibers of the 7d were significantly reduced compared with the 3d, there were only a very small number of CGRP-positive fibers at the 14d, and almost no CGRP-positive fibers at the 21d and 28d. Many varying thickness CGRP-positive fibers can be seen in the injury part of the nerve at the 1d of the bFGF group, and a large number of fibers can still be found at the 3d, the fibers were significantly reduced compared with the 3d, and almost no positive fibers at the 14d.Conclusion1.Sciatic nerve injury can cause the dissolution of Nissl body in the anterolateral motor neurons of anterior horn(L4-6) and had no effect on the medial motor neurons; Sciatic nerve injury can cause the dissolution of Nissl body in the,DRG(L4-6) neurons.2.The synthesis of CGRP increased in the anrerolateral motor neurons of anterior horn and it reduced in some of large, medium and small DRG neurons after sciatic nerve injury.3. Exogenous bFGF can promote the synthesis of CGRP in the anterolateral motor neurons of the anterior horn of the spinal cord and in small and medium neurons of DRG, it had no effect on the expression of CGRP in large DRG sensory neurons.4.Exogenous bFGF can promote the survival of the imparied motor neurons and small and medium sensory neurons of DRG. |
PDF Full Text Request