Study on after-effect of electroacupuncture with different time intervals on corticospinal excitability in primary motor cortex / 中国针灸

OBJECTIVES@#To compare the effects of electroacupuncture (EA) with different time intervals on corticospinal excitability of the primary motor cortex (M1) and the upper limb motor function in healthy subjects and observe the after-effect rule of acupuncture.@*METHODS@#Self-comparison before and after intervention design was adopted. Fifteen healthy subjects were included and all of them received three stages of trial observation, namely EA0 group (received one session of EA), EA6h group (received two sessions of EA within 1 day, with an interval of 6 h) and EA48h group (received two sessions of EA within 3 days, with an interval of 48 h). The washout period among stages was 1 week. In each group, the needles were inserted perpendicularly at Hegu (LI 4) on the left side, 23 mm in depth and at a non-acupoint, 0.5 cm nearby to the left side of Hegu (LI 4), separately. Han's acupoint nerve stimulator (HANS-200A) was attached to these two needles, with continuous wave and the frequency of 2 Hz. The stimulation intensity was exerted higher than the exercise threshold (local muscle twitching was visible, and pain was tolerable by healthy subjects, 1-2 mA ). The needles were retained for 30 min. Using the single pulse mode of transcranial magnetic stimulation (TMS) technique, before the first session of EA (T0) and at the moment (T1), in 2 h (T2) and 24 h (T3) after the end of the last session of EA, on the left first dorsal interosseous muscle, the amplitude, latency (LAT), resting motor threshold (rMT) of motor evoked potentials (MEPs) and the completion time of grooved pegboard test (GPT) were detected. Besides, in the EA6h group, TMS was adopted to detect the excitability of M1 (amplitude, LAT and rMT of MEPs) before the last session of EA (T0*).@*RESULTS@#The amplitude of MEPs at T1 and T2 in the EA0 group, at T0* in the EA6h group and at T1, T2 and T3 in the EA48h group was higher when compared with the value at T0 in each group separately (P<0.001). At T1, the amplitude of MEPs in the EA0 group and the EA48h group was higher than that in the EA6h group (P<0.001, P<0.01); at T2, it was higher in the EA0 group when compared with that in the EA6h group (P<0.01); at T3, the amplitude in the EA0 group and the EA6h group was lower than that of the EA48h group (P<0.001). The LAT at T1 was shorter than that at T0 in the three groups (P<0.05), and the changes were not obvious at the rest time points compared with that at T0 (P > 0.05). The GPT completion time of healthy subjects in the EA0 group and the EA48h group at T1, T2 and T3 was reduced in comparison with that at T0 (P<0.001). The completion time at T3 was shorter than that at T0 in the EA6h group (P<0.05); at T2, it was reduced in the EA48h group when compared with that of the EA6h group (P<0.05). There were no significant differences in rMT among the three groups and within each group (P>0.05).@*CONCLUSIONS@#Under physiological conditions, EA has obvious after-effect on corticospinal excitability and upper limb motor function. The short-term interval protocol (6 h) blocks the after-effect of EA to a certain extent, while the long-term interval protocol (48 h) prolongs the after-effect of EA.

Electroacupuncture at "Jiaji" (EX-B2) induced down-regulation of OX-42 and P2X4 in lumbar spinal cord contributes to its analgesic after-effect in rats with chronic constriction injury / 针刺研究

OBJECTIVE: To investigate the effect of electroacupuncture (EA) at "Jiaji" (EX-B2) at different time points on the expression of OX-42 (a monoclonal antibody with specific expression of complement receptor-3 in spinal microglial cells) and purinergic receptor P2X4 (P2X4) in rats with chronic constriction injury (CCI) of the sciatic nerve, as well as the possible after-effect mechanism of EA analgesia in neuropathic pain. METHODS: Sprague-Dawley rats were randomly divided into blank group, model group, immediately after EA group, 0.5-hour after EA group, 1-hour after EA group, 2-hour after EA group, 4-hour after EA group, 12-hour after EA group, and 24-hour after EA group, with 6 rats in each group. The rats in the model group and the EA groups were used to establish a model of CCI-induced neuropathic pain, and those in the immediately after EA group and the 0.5, 1, 2, 4, 12 and 24 hours after EA groups were treated with EA at bilateral L3 and L5 "Jiaji" points for 20 min after 7 d of modeling. Samples were collected immediately and at 0.5, 1, 2, 4, 12, and 24 hours after EA, and for the rats in the blank group and the model group, samples were collected after fixation the rats for 20 min. Heat pain threshold was observed before and after intervention, and immunohistochemistry was used to measure the protein expression of OX-42 and P2X4 in the spinal cord lumbar enlargement. RESULTS: After 7 days of modeling (before intervention), compared with the blank group, the heat pain threshold had a significant reduction in the model group and the EA groups (P<0.01). Compared with the model group after intervention, the immediately after EA group and the 0.5, 1 and 2 hours after EA groups had a significant increase in heat pain threshold (P<0.05). Compared with the model group, immediately after EA, the 0.5, 1 and 2 hours after EA groups had a significant reduction in the protein expression of OX-42 (P<0.01), and immediately after EA, the 0.5 and 1 hour after EA groups had a significant reduction in the protein expression of P2X4 (P<0.01). CONCLUSION: EA at "Jiaji" points can significantly increase heat pain threshold and down-regulate the protein expression of OX-42 and P2X4 in the spinal cord of CCI rats. The analgesic effect can last for 2 h.

The after-effect of short-term use of losartan on blood pressure and myocardium in prehypertension rats / 重庆医学

Objective To observe the influence of losartan on rats′blood pressure and myocardium.Methods To randomly divide 24 4-year-old spontaneously hypertensive male rats into 3 groups.Group A is given normal saline(NS);group B is given losartan 20 mg/kg in 4-week-old;group C is given the same dose in 1 2-week-old;To take another 4-week-old male wistar rats to form group D,feed NS served as normal comparison.Each group was given NS or losartan one time each day through intragastric administration for 4 weeks.Follow up 24 weeks after stopping the medicine.Rats’SBP were measured through tail cuff method respectively when at 4,8,12,16,20 and 24 weeks’ time.After 24 weeks,cut off the head to take the sample,the RVW/BW,HW/BW,LVW/BW were measured through weighing method.To observe the morphologic change of the cardiac muscles and measure the area of myocardium cell cross section through HE stain method.Ra-dioimmunoassay was used to measure the AngⅡand Aldo level of the blood plasma and myocardium.Results At the age of eight-week,the SBP of group A and C are higher than those of group D(P0.05).About LVW/BW,HW/BW and the ar-ea of myocardium cell cross section,group A increased significantly in comparison with group D (P<0.05),group B and C decreased in comparison with group A(P<0.05),group B decreased significantly in comparison with group C(P<0.05).Through the observation of the area of myocardial cell cross section under the microscopy,group A increased significantly in comparison with group D about myocardial cell fattened and the gap between cells are widened,the fibers of mesenchyma proliferates.group B and D are similar,group C is between group B and A.The level of AngⅡand Aldo in plasma and myocardium of group A increased significantly in comparison with group D (P<0.05),group B decreased significantly in comparison with group A and C(P<0.05).Conclusion To use losartan for a short time in trea-ting rats with prehypertension can get the after-effect of reducing blood pressure and anti-ventricular-remodeling.