An experimental study of axoplasmic flow tracing using 125Iodine horseradish paroxidase

Abstract

Objective To study the feasibility of tracing axoplasmic flow by 125Iodine horseradish paroxidase (125I-HRP) in order to provide the experimental basis for study of nerve regeneration using radioisotope. Methods Twenty - four SD rats were divided into control group and experimental group. In the experimental group, the right sciatic nerve of the rat was transected at the site 0.8 cm distal to the sciatic notch and then sutured immediately. Four weeks later, 125I - HRP was injected into the right soleus muscles. In the control group, Only injection of 125I - HRP into the right soleus muscles was done. 24 hours after HRP injection, sciatic nerve segment 0.8 cm in length proximal to the suture site of the experimental group and distal to the sciatic notch in the control group were harvested respectively. The muscle around the nerve and the left sciatic nerve segment at the corresponding level were also harvested. 125Iodine counting was done. Results The intensity of radioactivity of 125Iodine in the sciatic nerve of the injection side in the control group was 30 times of that in other tissues. In the experimental group, the 125Iodine radioactivity of the sciatic nerve of the injection side was 6 times of that in the muscles around the nerve and 7 times of that in the left sciatic nerve. The difference was statistically significant. Conclusions 125I - HRP injected into the muscle can be absorbed by nerve endings and be transported by retrograde axoplasmic flow to pass through the anastomosis site and reach the proximal nerve segment. The intensity of radioactivity of 125Iodinein in nerve tissue can be detected by г -counting.