An Exploration On The Relation Between NT-4, IGF-I And The Plasticity Of Spinal Cord As Well As Acupuncture Promoting Apinal Cord Plasticity

Objective: To explore the changes on expression of NT-4 and IGF-I in spared dorsal root ganglia (DRG, L6) in operated/acupuncture side and unoperated /unacupuncture side, spinal lamina II (L3, L5, L6) and Clarke' nucleus (L3) of normal adult, partial dorsal rhizotomy and acupuncture spared DRG cats so as to know the relation between NT-4, IGF-I and the plasticity of spinal cord as well as acupuncture promoting spinal cord plasticity.Methods: 25 adult cats were divided into 5 groups: normal control group; unilateral partial root rhizotomy 7th day and 14th day groups (unilateral L1-L5, L7-S2 DRG were transected, but L6 DRG was spared); acupuncture spared DRG 7th day and 14th day groups (electro-needle stimulation was performed following unilateral partial root rhizotomy). Animals survived for 7 or 14 days after operation respectively. Bilateral L6 dorsal root ganglia and L3, L5, L6 spinal cord of every group were made into 20um frozen sections. Then, sections were stained under the same condition using specific NT-4 (1:200) and IGF-I (1:200) antibody by the immunohistochemistry ABC method. The distribution and the number of NT-4 and IGF-I positive neurons in bilateral spared DRG (L6) in operated/acupuncture side and unoperated/acupuncture side, spinal lamina II (L3, L5, L6) and Clarke' nucleus (L3) of each animal were oberserved and counted. All data were analyzed by one-way anova, SNK-q test and paired-t test.Result: 1. The expression changes of NT-4 and IGF-I after partial dorsal rhizotomy and acupuncture in spared L6 DRG1.1 In normal adult cats, NT-4 and IGF-I immunoreactivity was observed in both large sized and medium-small sized neurons of L6 DRG. After partial dorsal root rhizotomy 7 days, the number of NT-4 positive neurons in spared DRG in operated side decreased than that of normal group (P<0.05) , but increased than that of L6 DRG in unoperated side (P<0.05) ; Thenumber of NT-4 positive neurons of L6 DRG on the 14th day after partial dorsal root rhizotomy was also lesser than that of normal, 7th day groups and seen in unoperated side (P<0.05) . After partial dorsal root rhizotomy 7 days, the number of IGF-I positive neurons in spared DRG in operated side also showed declination than that of normal group (P<0.05) , but has no apparent change compared with that of L6 spared DRG in unoperated side (P>0.05) ; On the 14th day, IGF-I expression in neurons of L6 DRG in operated side was also significantly lower than that of L6 spared DRG in unoperated side(P<0.01), but had no differences compared with that of 7th day group (P>0.05) .1.2 After acupuncture spared DRG 7th day, the number of NT-4 positive neurons in spared DRG in acupuncture side showed significant declination than that of normal and 7th day operation groups (P<0.05) , but increased than that of L6 spared DRG in unacupuncture side (P<0.05) ; In 14th day group, NT-4 expression in neurons of DRG in acupuncture side increased apparently than that of 14th day operation group and seen in unacupuncture side and came back to normal horizon. After acupuncture spared DRG 7th day, the number of IGF-I positive neurons in spared DRG in acupuncture side showed significant increase than that of 7 day operation groups (P<0.05) , but declination than that of normal group (P<0.05) , and had no significant change compared with that of DRG in unacupuncture side (P,0.05) ; In 14th day group, IGF-I expression in neuron of L6 DRG in acupuncture side also increased apparently than that of 14th day operation group and came back to normal level, but declined than that of L6 spared DRG in unacupuncture side (P<0.05) . After acupuncture spared DRG 14th day, the numbers of NT-4 and IGF-I positive neurons in spared DRG in acupuncture side were significant increase than that of 7th day group after acupuncture (P<0.05 ) . 2. The expression changes of NT-4 and IGF-I in spinal lamina II and Clarke's nucleus after partial dorsal rhizotomy and acupuncture2.1 In normal adult cats, NT-4 and IGF-I immunoreactivity was observed in neurons and glial cells of spinal lamina II (...