Objective: To explore the action mechanisms of transcutaneous electrical acupoint stimulation (TEAS) on prevention and treatment of orthodontic toothache.
Methods: Twenty-four male New Zealand rabbits were randomly divided into a blank group, an orthodontic group and a TEAS group, 8 rabbits in each one. The orthodontic model of rabbit was made in orthodontic group and TEAS group by bonding brackets and fixing NI-TI screw with ligature wire. After model establishment, the TEAS group was treated with TEAS at ashi points (skin surface corresponding points to the bilateral upper 1st molars) and "Hegu" (LI 4) with dilatational wave, 20 min per treatment, twice a day, totally 2-day consecutive treatment (4 treatments) was provided. The rabbit general behavior, total food intake and threshold of pain were observed; the contents of serum prostaglandin E2 (PGE2), granulocyte macrophage colony stimulating factor (GM-CSF) as well as endorphin (β-EP) fluid and cholecystokinin-8 (CCK-8) in cerebrospinal fluid (CSF) were detected.
Results: Compared with the orthodontic group, the rabbit general behavior, total food intake and threshold of pain in the TEAS group were significantly improved (P<0.05, P<0.01). The serum PGE2 were significantly reduced (P<0.05), while GM-CSF presented reducing trend without statistical significance (P>0.05). The β-EP in the CSF were increased (P<0.05), while CCK-8 in CSF presented reducing trend without statistical significance (P>0.05).
Conclusions: The preventive and therapeutic effects of TEAS on rabbits with orthodontic toothache are achieved by reducing algogenic substance PGE2 in peripheral nervous system selectively, increasing β-EP in CSF in central nervous system and keeping the level of anti-opioid pain maintaining substance CCK-8.Both the central and peripheral nervous systems participate in the analgesic effect of TEAS.
Keywords: analgesic mechanism; orthodontic toothache; preventive and therapeutic effect; transcutaneous electrical acupoint stimulation (TEAS).