备用背根猫脊髓背核组织提取液对鸡胚背根节神经突起生长的影响

THE NEURITE-OUTGROWTH-PROMOTING EFFECT OF TISSUE EXTRACT FROM CLARKE'S NUCLEUS OF CAT SPINAL CORD WITH SPARED DORSAL ROOT PREPARATION ON CULTURED DORSAL ROOT GANGLION OF CHICKEN EMBRYO

应用Liu和Chambers创立的备用背根模型,切除成年雄猫(5只)一侧的L_1～L_5、L_7～S_2背根节,保留L_6背根为备用背根,术后动物存活5d。分别制备脊髓T_(12)～L_3节段手术侧(实验组)、非手术侧(对照组)背核组织及其条件培养液。以Hanks平衡盐溶液的条件培养液作为参照组。用实验组、对照组以及参照组条件培养液对Hamburger 35期Leghorn鸡胚腰段背根部进行悬滴法培养,每只动物进行一批实验。于培养24h,48h观察测量各个背根节神经突起的平均长度。在各组背根节从培养24h到48h神经突起明显增长的基础上,求出每批培养物实验组、对照组背根节平均突起长度与参照组平均突起长度的比值以及5批培养物之平均比值。比较实验组、对照组平均比值在同一观测时间内的差异,发现两个观测时间实验组平均比值都明显大于对照组者。结果提示,猫脊髓经部分去后肢背根传入后,背核组织提取液促进神经突起生长的作用增强。

Spared dorsal root preparation originated from Liu and Chambers was applied. Five adult male cats with Unilateral hind-limb posterior rhizotomy from L1 to S2 except L6 were used. Tissues of Clarke's nuclei in spinal segments from T12 to L3 of both operated (experimental) and unoperated (control) sides were dissected 5 days after operation and the tissue extracts were made with Hanks balanced salt solution (Hanks BSS). Conditioned media for both experimental group and the control contained 1/3 extracts and 2/3 Eagle's MEM, and for a reference group Hanks BSS was used instead of tissue extracts. Dorsal root ganglia (DRG) from chicken embryos at Hamburger stage 35 were cultured with the above conditioned media by employing a modified hanging drop technique, one animal for one batch of cultures. Microphotographs of every DRG were taken at 24 and 48 hours of incubation and the average neurite length were measured The differences between the two time groupSwere compared. On the basis of significant neurite extension from 24 to 48 hours of the cultured DRG in all groups, the relative neurite-outgrowth-promoting effects were represented by the ratios of the average reurite length of experimental or the control group to the reference one. Mean ratio value of 5 cats was calculated and the difference between experimental group and the control at the same test time was compared. The findings demonstrated that ratio value of experimental group was significantly greater than that of the control at the two test times. Suggestion might be drawn out of this result that an increased neuriteoutgrowth-promoting effect appeared in the tissue extracts of Clarke's aucleus of partially deafferented spinal cord of cat.