| Purpose: TO investigate the different expression of Laminin and Fibronectin in the optic nerve and sciatic nerve of the rats during the different developing stages , to determine the expression of LN and FN in the optic nerve regeneration model, to detect the value of the LN ,FN and the effects of the sciatic nerve transplation in the optic nerve regeneration after transection.Methods: In the first part, 50 SD rats were randomly divided into five groups according to the postnatal days ,such as postnatal day 7(p7), p15 ,p30, p45and p60 . Both optic nerve and sciatic nerve were taken from them and determined the expression of LN and FN by immunohistochemistry. The immunohistochemistry stainings were analyzed by automatic image analysis technology. In the second part, 80 SD adult rats were randomly divided into two groups. 40 rats belonged to the experiment group, the rest comprised the control group . The right optic nerve was transected in all rats. The two kinds of the optic nerve regeneration models were set up. In the experiment group , a 15mm segment ofautologuous sciatic nerve in the right was anastomosed to the distal optic nerve stump. In the control group , the cut ends of optic nerve were reapproximated by sutures without inserting a graft. Animals were allowed to survive for 15, 30, 45and 60 days . The expression of LN and Fn in the regeneration models were examined by immunohistochemistry . The immunohistochemistry stainings were analyzed by automatic image analysis technology. Also electron microscopic was used to observe the regrown nerve axons .Results : 1 .Immunohistochemistry study showed LN and Fn were detected in both the optic nerve and the sciatic nerve of the normal SD rats.2.The expression of LN and FN in the sciatic nerve were significantly higher than that in the optic nerve (p<0.05).3.The expression of LN and FN in the sciatic nerve and the optic nerve of the younger rats were significantly higher than that in the elder rats.(p<0.05). The younger expressed more.4.In the mature rats, the expression of LN and FN in the sciatic nerve was a lot, but that in the optic nerve was little.5.The expression of LN and FN in the sciatic nerve transplation model was significantly higher than that in the other regeneration model p<0.05).6.Optic nerve outgrowth could be seen within the artificial sciatic nerve graft in the adult rat 15 days after transplation.T.Remyelination was seen by electron microscopic observation in the experiment group .Conclusions: These data showed there are significantdifference in the LN and FN (belong to the ECM which were promoting factors for regeneration)from the optic nerve and the sciatic nerve. They were rich in the sciatic nerve, even in adult rats. The sciatic nerve could regenerate easily after injury. But by contrast, the optic nerve owned little. The adult mammalian optic nerve did not regenerate following lesion. That may be relation with the different ability of regeneration between them. Since the sciatic nerve could offer trophic support and a substrate for growth. Anastomsing a sciatic nerve graft onto the transected optic nerve stump to induce regeneration. These results demonstrated regeneration of axons in the completely transected optic nerve was promoted by implanted a segment of sciatic nerve to the cut stump, whilst the regrowth of retinal fibres became directed into sciatic nerve . The data also indicated the potential regenerating ability of the optic nerve in the adult nerve and the optic nerve could regenerate within the sciatic nerve . The graft made by the sciatic full of ECM could provide the environment for the regeneration of retinal ganglion cell (RGC) axons in the adult rats. It may soon be possible to preserve and restore vision lost from disease or damage to the optic nerve. |
PDF Full Text Request