Determination of Temperature-time Curve of Two Mild Moxibustion Methods: Reinforcing and Reducing

Song Xian, Wei Jian-zi, Mao Hui-juan, Zhao Ling, Shen Xue-yong

College of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China

Determination of Temperature-time Curve of Two Mild Moxibustion Methods: Reinforcing and Reducing

Song Xian, Wei Jian-zi, Mao Hui-juan, Zhao Ling, Shen Xue-yong

College of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China

Objective: To observe the specificity of reinforcing and reducing methods of mild moxibustion and explore its clinical significance.

Methods: Thirty healthy students were selected and given reinforcing of mild moxibustion on the left Neiguan (PC 6) and reducing on the right Neiguan (PC 6) respectively. Temperature of the acupoint skin surface and the temperature-time curve were recorded by a digital thermometer.

Results: In application of mild moxibustion on Neiguan (PC 6), there was a statistical difference in the temperature-increase section between reinforcing and reducing methods (P＜0.01). The temperature-increasing section of the temperature-time curve in the reducing method was obviously steeper than that in the reinforcing method. In the period of 0.5-3 min during moxibustion, the temperature of Neiguan (PC 6) was remarkably higher in the reducing than in the reinforcing (P＜0.01). In the application of the reducing, the time for the temperature of Neiguan (PC 6) to increase to 40℃ was remarkably advanced (P＜0.05) and the rate of burning pain in the subjects was remarkably higher in the reducing method than in the reinforcing method (P＜0.001).

Conclusion: In comparison with the reinforcing method, the acupoint temperature increased more quickly in the application of reducing method and can produce obvious hot stimulation in a short period of time. In the application of the reinforcing method, the acupoint temperature increased mildly and could enhance the tolerance of the organism to the high temperature.

Moxibustion Therapy; Mild Moxibustion; Suspended Moxibustion; Reinforcing-reducing Manipulations

The description of the reinforce-reducing manipulations by moxibustion is earliest seen in Ling Shu (Miraculous Pivot). It tells that “when fire is used for reinforcing, do not blow off its fire and let it go away itself; when fire is used for reducing, quickly blow off its fire, and fire should be extinguished, in order to transmit moxa efficacy.”[1]The medical practitioners in later generations mostly follow this method in the application of moxibustion for reinforcing or reducing. But, there are fewer reports about the study on differences between two of them.

The heating effect produced during treatment of diseases by moxibustion is the key to achieve the therapeutic effects[2-4]. To observe the changes of the local temperature of the acupoints in the application of moxibustion forreinforcing and reducing is significantly important for understanding the functional mechanism of moxibustion for reinforcing and reducing. In this study, the acupoint temperature-time curve in mild moxibustion on Neiguan (PC 6) for reinforcing and reducing is measured and comparatively analyzed. Now, the report on the experimental results is given as follows.

1 Experimental Subjects and Observed Acupoints

1.1 Inclusion criteria

Students, physically and psychologically healthy, without a history of cardiac, hepatic, renal and cerebral diseases, without a history of mental disorders and without a history of dermal diseases, with the age ranging from 20-28 years old, who were willing to participate in the study and with good compliance, were recruited.

1.2 General information

Totally, 30 subjects were recruited, including 15 males and 15 females, at the average age of (25.03 ±1.52).

1.3 Observed acupoints

The observed acupoints were bilateral Neiguan (PC 6) and the acupoints were selected in accordance with the Location of Acupoints (state standard of the People’s Republic of China, GB 12346-90).

2 Experimental Methods

2.1 Experimental instruments and materials

UT-325 digital thermometer, UT-T01 point thermocouple (produced by Shanghai Uni-Trend Electronics Company, temperature measurement range from -40 ℃ to 1 000 ℃), USD small fan (weighing 0.2 kg, and size 13 cm × 10 cm × 8.5 cm), pure moxa roll (produced by Nanyang Chinese Medical Moxa Wool Co., Ltd., 18 mm × 200 mm), self-made air duct (a tapered air guide made of a piece of white paper in size of A4, with a small hole of 1 cm in diameter on top of the taper, stuck on the top of a square paper box), (Fig.1).

2.2 Experimental environment

The temperature in the laboratory was controlled by central air-conditioning system at 20-25℃, with the relative humidity at 45%-65%, and without obvious ventilation in the room.

2.3 Operating methods

2.3.1 Reinforcing by mild moxibustion

The subjects took a sitting position with the left hand on the treatment table to expose Neiguan (PC 6). After ignited, a moxa roll was put 2.5 cm straightly away Neiguan (PC 6)[5], (Fig.2).

Fig.1 Self-made air duct

Fig.2 Reinforcing method by mild moxibustion

2.3.2 Reducing by mild moxibustion

The subjects took a sitting position with the right hand on the treatment table to expose Neiguan (PC 6). At the same time, a small fan was used to blow wind through the self-made air guide toward the ignited moxa roll, with a wind speed at 2 m/s, (Fig.3).

For the same subject, the interval between reinforcing and reducing methods was longer than 15 min.

2.4 Determination of acupoint temperature

The probe of the digital thermometer was closely stuck on the skin surface of Neiguan (PC 6), and the automatic recorder of thermometer was closely stuck on the skin for acupoint temperature. One sample was taken every 0.5 min (each temperature sample was measured for three times for taking the average value). Both the reinforcing method and reducing method were measured respectively for 10 min, and totally 21temperature samples were collected. The temperaturetime curve was formed by 21 samples.

Fig.3 Reducing method by mild moxibustion

2.5 Recording burning pain in the experimental subjects

In the application of moxibustion, the burning pain on the acupoint skin the subject felt at any time was recorded as “the burning pain from mild moxibustion”, and otherwise was recorded as “no burning pain from moxibustion”. The burning pain rate was respectively calculated in the two groups of the subjects.

Burning pain rate = (Number of subjects with burning pain in each group/Number of experimental subjects in each group) × 100%.

2.6 Statistical methods

All data were used to build database by Microsoft Word Excel and summarized and analyzed by SPSS 17.0 professional statistical software. In the same time period, the general temperature-time curve of reinforcing and reducing by mild moxibustion was compared by difference analysis of repeated measurement. The temperature in the same time period between the different groups was expressed by (), and the data was processed with the normality test and variance homogeneity test. Those in conformity with the normal distribution were processed by paired t-test. Those not in conformity with the normal distribution were processed by twoindependent-sample test. In the application of mild moxibustion for reinforcing and reducing methods, the comparison of the times needed for the temperature to increase to 40 ℃ was processed by paired t-test. The comparison of the burning pain rate between the two groups was processed by Chi-square test.

3 Experimental Results

3.1 Comparison of acupoint skin temperature-time curve between reinforcing and reducing

Please see Fig.4 for the curve of acupoint temperature changing with the time in reinforcing and reducing by mild moxibustion. The difference between reinforcing and reducing methods was mainly manifested in the temperature-increasing section. The temperature-increasing curve was obviously steep in the reducing than in the reinforcing. The least-significant difference (LDS) was used to compard the temperature-increasing section (the prior 240 s of the temperature curve) of reinforcing and reducing methods. The results showed that the temperature curves of reinforcing and reducing methods was significantly different (P＜0.01).

In the comparison of the temperature in two curves at the same timing, the normality test was used for data of the two groups firstly. The data of acupoint temperature were not in the normal distribution at 60 s, 90 s, 120 s, 210 s and 240 s after moxibustion. The temperature data at those time points were processed by non-parametric analysis. The temperature data at the rest time points were processed by paired t-test.

Before moxa roll was ignited (i.e. 0 s), there was no statistical difference in the acupoint skin temperature in the subjects between the two groups (P=0.312). In the period of 30-180 s after moxibustion, there was statistical difference in the temperature between reinforcing and reducing. The temperature was obviously higher in the reducing than in the reinforcing (P＜0.01). From 210 s of moxibustion to the end of the observation, there was no statistical difference in the acupoint skin temperature of the subjects between the two groups (P＞0.05), (Fig.4).

Fig.4 Acupoint temperature-time curve of reinforcing and reducing methods (compared with the reinforcing method, ＊P＜0.01)

3.2 Comparison of the time needed for acupoint temperature to increase to 40 ℃ in reinforcing and reducing methods

The study showed that the physiological effect could only be produced by heating stimulation over the temperature of 40 ℃[5-7]. Therefore, in this study, the times that the acupoint temperature reached 40 ℃ in the application of reinforcing and reducing by mild moxibustion were compared. The results showed that the time for the acupoint temperature to reach to 40 ℃in the reinforcing method was (3.07±1.40) s, versus (1.75±1.57) s in the reducing method. There was a statistical difference between the two methods (P＜0.05), (Fig.5).

Fig.5 Time needed for acupoint temperature to reached 40 ℃in reinforcing and reducing methods by mild moxibustion (compared with the reducing method, ＊P＜0.05)

3.3 Comparison of burning pain rate between the subjects in reinforcing and reducing

The burning pain rate was 33.3% in the subjects applied with the reinforcing by mild moxibustion and 90.0% in the subjects applied with the reducing, with a statistical difference (P＜0.001), indicating that the operation of the reducing method is much easier for the subjects to have the burning pain (table 1).

Table 1. Comparison of burning pain rate between reinforcing and reducing methods (case)

4 Analysis and Discussion

The description about reinforcing and reducing by moxibustion is seen in Ling Shu and was developed by many medical practitioners in the later generations. But, modern studies about reinforcing and reducing are fewer. Some studies believe that reinforcing and reducing effects are realized by regulating the stimulation amount during moxibustion, and the expected reinforcing or reducing effect could be achieved by mastering the best stimulation amount. The strong stimulation and short stimulating time would produce the fast speed of the physiological stimulation amount, as the reducing, and vice versa[8]. Reinforcing and reducing effects by moxibustion are also different. The reinforcing has the effects to warm up and replenish the spleen and kidney, restore yang and avoid prostration, and the reducing has the specific effect to control heat production[9]. Judging from the amount-effect relationship, most studies give this conclusion that “comparative large amount of stimulation could have better therapeutic effect”. For instance, strong stimulation of moxa roll moxibustion could have the good regulatory effect for the gastric electric activity in rabbits, better than the control group with weak stimulation[10]. In the group of strong stimulation with the warm needling moxibustion, the clinical symptoms of the patients with knee osteoarthritis in pattern of yang deficiency and cold accumulation could be improved satisfactorily, with anesthetic effect better than the weak stimulation group and medium stimulation group[11]. The improving effect of cellular immune mechanism in rats with asthma is better in the group with suspended moxibustion by large amount on Dazhui (GV 14) than in the group by small amount[12].

The results in this experiment show that surely there is certain difference in the temperature-increasing effect of the acupoints by reinforcing and reducing by traditional mild moxibustion. This type of difference is mainly manifested by that the temperature-increasing effect of the acupoints is harmonious and slow in the reinforcing than in the reducing. Three minutes prior to the application of moxibustion, the acupoint temperature is remarkably higher in the reducing than in the reinforcing by mild moxibustion (Fig.1). Although moxibustion is applied at the same time, the reducing by mild moxibustion could enable the acupoint temperature to reach 40℃ by quicker speed[5-7]. And the speed of the acupoint temperature by the reinforcing to reach the effective temperature is slower (Fig.2). What is the relationship between the different temperature-increasing modes of reinforcing and reducing method by mild moxibustion on the acupoints and moxibustion effects? It needs investigation in the future experiments.

The experimental results also indicate that the harmonious and moderate temperature-increasing effect of the reinforcing on the acupoints canremarkably enhance the tolerance of the organism to high temperature. Regardless of the reinforcing or reducing method by mild moxibustion, two types of moxibustion modes can finally enable the acupoint temperature to increase to 41.8 ℃, without difference in the highest temperature of the acupoints between the two types of moxibustion. But, the burning pain rate is far lower in the subjects in the reinforcing group than in the reducing group (table 1). The experimental results indicate that the tolerance of high temperature of the acupoints could be elevated by slow temperatureincreasing mode, so as to increase the moxibustion amount[10-12]. Whether the increase of moxibustion amount would be able to enhance the therapeutic effect needs further investigation.

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[10] Liu NY, Zhang R, Zhang JY, Zhao M, Ma C, Yang ZM. Influence of stimulating Zusanli (ST 36) with different quality, quantity of moxa and type of moxibustion on electrogastroactivity of rabbits. Zhenci Yanjiu, 1997, 22(3): 173-175.

[11] Hong KD, Wan T, Li L, Wu MX, Liu XX. Warming needle moxibustion with different moxibustion intensity in treating knee osteoarthritis with yang deficiency and cold coagulation syndrome: comparison of analgesia and semiotic improvement. Zhongguo Zuzhi Gongcheng Yu Linchuang Kangfu, 2010, 14(41): 7748-7752.

[12] Zhang W, Chen MR, Xiong J. Effects of different quantity of moxibustion at "Dazhui" (GV 14) on cellular immunity in asthma rats. Zhenci Yanjiu, 2012, 37(3): 202-205.

Translator: Huang Guo-qi

R2-03

A

Date: January 5, 2013

Author: Song Xian, master degree candidate.

Wei Jian-zi, M.D., professor. E-mail: weijz2000@yahoo.com.cn