[Effect of electroacupuncture at different acupoints on expression of cervico-spinal GDNF and BDNF and their receptor genes in neck-incision pain rats].
OBJECTIVE
To observe the effect of electroacupuncture (EA) of "Futu" (LI 18), etc. on the expression of genes of glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF) and their receptors in the cervico-spinal cord in neck-incision pain rats, so as to study its mechanism underlying incision-pain relief.


METHODS
A total of 50 Sprague Dawley male rats were randomly divided into normal, model (incision pain), EA-Futu (LI 18), EA- Hegu (LI 4) - Neiguan (PC 6, LI 4-PC 6) and EA-Zusanli (ST 36)-Yanglingquan (GB 34, ST 36-GB 34) groups (n = 10/group). A 1.5 cm long longitudinal incision was made along the midline of the neck under anesthesia to duplicate neck-incision pain model. Thermal pain threshold (PT) was measured before and after modeling and after the treatment, respectively. EA (1-2 mA, 2 Hz/100 Hz) was applied to bilateral LI 18, PC 6-LI 4 and ST 36-GB 34 for 30 min. The expression of genes of GDNF and its receptor GFRalpha-1, and BDNF and its receptors TrkA, TrkB in the spinal cord (C1 - C4) tissue was detected by quantitative real-time-PCR.


RESULTS
In comparison with pre-modeling in the same one group, the thermal PT levels were decreased obviously in the model, LI 18, LI 4-PC 6 and ST 36-GB 34 groups after neck incision (P < 0.05). Compared with the model group, the PT levels were increased markedly in LI 18, LI 4-PC 6 and ST 36-GB 34 groups after the EA treatment (P < 0.05). Correspondingly, the expression levels of spinal GDNF mRNA and GFRalpha-1 mRNA were obviously lower, as well as BDNF mRNA was markedly higher in the model group than in the control group (P < 0.05), and those of TrkA mRNA and TrkB mRNA were increased slightly in the model group than in the control group (P > 0.05). In comparison with the model group, the expression levels of spinal GDNF mRNA and GFRalpha-1 mRNA were up-regulated considerably (P < 0.001), whereas those of BDNF mRNA, TrkA mRNA and TrkB mRNA were decreased slightly (P > 0.05) in the LI 18, LI 4-PC 6 and ST 36-GB 34 groups after EA treatment.


CONCLUSIONS
EA stimulation can significantly suppress pain reaction of neck incision, which is closely associated with its effects in up-regulating the expression of GDNF and its receptor GFRalpha-1 genes in the cervical spinal cord (C1 - C4).
Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.
Shao-Jun
SJ
Wang
Lian-Hong
LH
Tan
Jun-Ling
JL
Liu
D015669:Acupuncture Points; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D015671:Electroacupuncture; D015870:Gene Expression; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D019547:Neck Pain / Q000235:genetics* / Q000378:metabolism / Q000601:surgery / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020813:Receptor, trkB / Q000235:genetics* / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism
D019208:Brain-Derived Neurotrophic Factor; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D020813:Receptor, trkB