The Effect Of Partial Dorsal Root Rhizotomy And Acupuncture On The Expression Of CNTF And PDGF In Spared Dorsal Root Ganglions

Objective To investigate the effect of partial dorsal root rhizotomy and acupuncture on the expression of CNTF and PDGF in spared dorsal root ganglion of adult cats.Method 20 adult healthy male cats were divided randomly into 4 groups: normal control group; bilateral partial dorsal root rhizotomy 3^rd day, 7^th day and 14^th day groups (bilateral L₁^L₅, L₇^S₂ DRGs were transected; but L₆ DRG was spared). Right side was acupunctured. (Two groups of xuewei including Zusanli and Xuanzhong, Futu and Sanyinjiao located in the distribution area of L₆ spinal nerve were electron-needle stimulated alternately). Acupuncture began at the operation day, once a day for 30 minutes. They were sacrificed on 3^rd , 7^th and 14^th day after operation , the bilateral L₆ DRGs were made into frozen sections. Then, the sections were stained under the same condition using specific CNTF (1 : 500) and PDGF (1 : 200) antibody by the immunohistochemistry ABC method. The distribution and the number of CNTF and PDGF positive neurons in spared DRGs were observed and counted. All data were analyzed by One-Way ANOVA, SNK-q test and Paired-Samples t-test.Results 1. The expression of CNTF in spared DRG after partial dorsal root rhizotomy and acupuncture: (1) In normal cats, CNTF immunoreactants can beobserved in some large and medium-small sized neurons of L6 DRG . After partial dorsal root rhizotomy, the number of CNTF positive total and medium-small sized neurons decreased apparently (P<0.05) at 3rd day and returned to normal level at 7th day and 14th day. Positive large neurons had no significant changes at each time point (P>0.05) . (2) Three days after acupuncture, there was no difference in two sides. The number of CNTF positive total, large and medium-small sized neurons of spared DRG on acupuncture side was more than that of unacupuncture side (P<0.05) at 7th day. Only the number of positive large neurons increased compared with that of unacupuncture side and the number of total and medium-small sized neurons had no difference in two sides at 14 th day. 2. The expression of PDGF in spared DRG after partial dorsal root rhizotomy and acupuncture: (1) In normal cats, PDGF immunoreactants can be observed in some large and medium-small sized neurons of 1,6 DRG.. After partial dorsal root rhizotomy, both the number of total and medium-small sized positive neurons decreased apparently at 3rd day and 7th day and returned to normal level at 14' day. The number of large positive neurons had no difference at each time point. (2) Three days after acupuncture, there was no difference in two sides. At the acupuncture 7th day, the number of total and large positive neurons was more than that of unacupuncture side and medium-small sized neurons has no difference in two sides. At the 14th day, total and medium-small sized neurons increased compared with that of unacupuncture side, and the number of large positive neurons has no difference compared with that of unacupuncture side. .Conclusion 1. CNTF, PDGF immunoreactants were observed in some large and medium-small sized neurons in L^ DRG of adult cats. It indicates that they were related to the functions of DRG neurons. 2. The expression of CNTF and PDGFafter partial dorsal root rhizotomy was down-regulated immediately. Maybe, one reason is that the function of the DRG neurons was restrained for spinal cord injury, and another is the enhancement of the transportion rate to spinal cord. Later, the expression of CNTF and PDGF returned to normal, It showed that the function of DRG was restoring, and part of CNTF, PDGF was transported to spinal cord for repairment. On the other hand, the expression of CNTF and PDGF varied in different kinds of neurons in different periods. 3. Acupuncture accelerated the expression of CNTF and PDGF at different time points. CNTF and PDGF may take part in the sprouting of spared DRG in spinal cord and they may contribute to the plasticity of spinal cord after injury.