RESUMEN
OBJECTIVE: To observe the effect of twirling-reinforcing or reducing needling manipulations on plasma acetylcholine (Ach) content and expression of nitric oxide synthetase (NOS) and cyclic guanosine monophosphate (cGMP) in thoracic artery tissue in stress-induced hypertension rats. METHODS: A total of 60 male rats were randomly divided into blank control, model, acupuncture (no-needle-manipulation) , twirling-reinforcing needling and twirling-reducing needling groups (n = 12 in each group). The stress hypertension model was established by giving the animals with noise and electric shock stimulation (paw), twice a day for 15 days. Acupuncture stimulation was applied to bilateral "Taichong" (LR 3) for 1 min, followed by retaining the needles for 20 min. The treatment was conducted once daily for 7 days. Systolic blood pressure of the rat's tail was detected with non-invasive method and plasma Ach, and NOS and cGMP contents in the thoracic artery tissue were measured using ELISA method. RESULTS: Compared with the control group, the systolic blood pressure was significantly higher in the model group after 15 days' stress stimulation (P < 0.01), while the contents of plasma Ach, arterial NOS and cGMP were markedly down-regulated (P < 0.01). Following 7 days' acupuncture interventions, the increased blood pressure was down-regulated in the no-needle-manipulation, twirling-reinforcing needling and twirling-reducing needling groups (P < 0.05, P < 0.01); and the decreased Ach and NOS in the 3 treatment groups, and cGMP levels in the twirling-reinforcing and twirling-reducing needling groups were remarkably up-regulated (P < 0.01, P < 0.05). No significant change of arterial cGMP content was found in the no-needle-manipulation group (P > 0.05). The effect of the twirling-reducing needling was superior to that of no-needle-manipulation and twirling-reinforcing needling in lowering blood pressure and raising plasma Ach content (P < 0.05, P < 0.01). CONCLUSION: The twirling-reducing needling of acupuncture has a significant anti-hypertensive effect in stress hypertension rats, which may be associated with its effects in raising blood Ach, and arterial NOS and cGMP levels.
