坐骨神经逆行示踪放射自显影显像的初步实验研究

Preliminary study of image in sciatic nerve by retrotracing and autoradiography

目的研究131碘-辣根过氧化物酶(131I-HRP)通过逆行示踪及放射自显影显像坐骨神经的可行性,为临床应用放射性同位素神经示踪成像提供实验依据。方法采用新西兰兔随机分为131I-HRP组、Na131I组、生理盐水组。在左侧小腿三头肌分别注入131I-HRP、Na131I或生理盐水500μl,于注射后6、12、24、48、72小时后处死动物,取左侧带小腿三头肌的坐骨神经全长行放射自显影和坐骨神经HRP组织化学染色。结果131I-HRP组注射后6小时局部肌肉组织显影;随着时间的延长,坐骨神经逐渐显影;注射后72小时,坐骨神经全长均有显影,背根神经节有显影。各时相点间坐骨神经自显影长度差异有统计学意义(P(0.01)。HRP组织化学染色显示注射后6小时坐骨神经远段有少量阳性纤维;12小时近段逐渐出现大量的HRP反应阳性纤维;注射后72小时,背根节内出现HRP阳性细胞和纤维。Na131I组和生理盐水组注射后未见坐骨神经显影和HRP阳性和纤维。结论131I-HRP可以在坐骨神经内逆行运输,采用放射自显影技术可以显示坐骨神经。

Objective To study the feasibility of image in sciatic nerve by autoradiography through 131Iodine horseradish peroxidase（ 131I- HRP） retrotracing and to provide the experimental evidence in neuroimaging by radioisotope. Methods New-Zealand rabbits were randomly divided into 131I-HRP group,Na131I group and saline group. Then 500μl 131I-HRP,Na131I or saline was injected intramuscularly in left triceps surae respectively and then sacrificed at 6,12,24,48 and 72 hours after the injection. The image of sciatic nerve was detected by autoradiography and histochemistry. Results After 131I.HRP injection,the image by autoradiography emerged in muscular tissue around injection site at 6 hours and gradually enhanced in distal segment of sciatic nerve with increasing time. The total length of sciatic nerve and dorsal root ganglion developed an image at 72 hours after injection. There was significant difference between each time pointas compared with the length of image（ P 〈 0.01 ）. No positive image emerged in muscular tissue and sciatic nerve at 72 hour in Na131I group and saline group by radiography except obscure image in local triceps surae after 6 hours in Na131I group. HRP histochemical staining found that there was a sprinkle fibers in distal segment of sciatic nerve in 131I-HRP group at 6 hours. Moreover, massive positive-HRP fibers were found at 12 hours,which could be found at full length of sciatic nerve at 72 hours. Also,HRP positiveneurons in dorsal root ganglion were found at 72 hours. However,no HRP positive ：fibers were found in Na131I and saline group. Conclusion 131I-HRP can be retrograde transported in sciatic nerve,which can be traced with autoradiography.