“Acupmoxa” is a hybrid word of “acupuncture” and “moxibustion” that more closely resembles the Chinese ideograph for this treatment. People in Western countries are more familiar with acupuncture, while moxibustion is less popular, partially due to the paucity of scientific studies. Although the evidence-based efficacy of moxibustion needs to be further clarified, the mechanisms by which moxibustion may work include temperature-related and nontemperature-related ones. Local somatothermal stimulation (LSTS), one type of moxibustion, is achieved by application of a heat source to and above the acupoint. Such mild heat stimulation of the acupoint induces little skin damage, in contrast to the burning effect of moxibustion, but does provoke mild oxidative stress in the viscera. Thus, preconditioned LSTS at the peripheral acupoints LR 14 and PC 6 of animals is able to induce visceral HSP70 expression and to protect the liver and the heart against ischemia-reperfusion injury. Nontemperature-related mechanisms include smoke, herbs, and biophysical (far infrared) stimulation. We conclude that LSTS, a remote preconditioning method, has potential clinical usefulness. However, evidence-based efficacy and safety studies involving large-scaled clinical trials are needed in order that this approach will pass muster with Western scientists.
“Acupmoxa” is a hybrid word of “acupuncture” and “moxibustion” that more closely resembles the Chinese ideograph for this treatment. Acupuncture describes a procedure involving penetration of skin areas (acupoints) by thin metallic needles, which is followed by manipulating the needles manually. Moxibustion describes a technique that applies heat to acupoints by burning compressed powdered herbal material at the acupoints to be stimulated. Acupuncture or moxibustion, either alone or in combination, can be applied when treating patients with a wide range of diseases [
In contrast to the development of Western medicine, which can be traced back to Hippocrates via a clear and distinct route, Chinese acupmoxa theory was already fully developed by the end of the 2nd century BCE. In 1972, documents written on silk scrolls in a Ma-Wang-Dui tomb sealed in 198 BCE were discovered in China. This discovery included documents that only relate to moxibustion and do not include any references to acupuncture or acupoints. The documents refer to eleven lines of channel (meridians), which suggests that the origins of moxibustion and of meridians are earlier than those of acupuncture and acupoints [
Classically, moxibustion is applied to patients with the use of nonmoxa or moxa sticks, and the latter can be applied either directly or indirectly [
Based on descriptions in the ancient Chinese literature, the therapeutic effects of moxibustion are associated with treating chronic symptoms related to “deficiencies” and to the prevention of human disorders. Previous studies have demonstrated that moxibustion is effective when used to treat cervical vertigo [
Since the late 20th century, it has been suggested that moxibustion increases fetal activity during the treatment period, cephalic presentation after the treatment period, and cephalic presentation at delivery [
As moxibustion is defined as a technique that applies heat to acupoints by burning herbal materials on the body surface, factors such as temperature, smoke, odor, and herbs are likely to be involved in the possible mechanisms by which moxibustion may work.
Conventional application of moxibustion evokes multiple sensory stimulations, including temperature, pressure, pain, touch, and smoke stimuli. To avoid difficulties with respect to data interpretation when there are moxibustion-induced multisensory stimulations, Chiu et al. used temperature as the only stimulator in their series of studies (Table
Effects of LSTS on peripheral acupoints on visceral functions of the corresponding organs.
Acupoints | Visceral functions | Mechanisms | References | |
---|---|---|---|---|
Regulatory molecules | Serum | |||
GB 24 | Motility of SO |
NO ↑ | Chiu et al | |
| ||||
BL 40 and BL 36 | Motility of anal sphincter |
NO ↑ | Jiang et al | |
| ||||
LR 14 | Protects the liver from subsequent I/R injury | HSP70 ↑ | I/R + LSTS versus I/R : ALT |
Lin et al., 2001 [ |
| ||||
PC 6 | Protects the heart from subsequent I/R injury | HSP70 ↑ | I/R + LSTS versus I/R : CPK |
Chiu et al |
| ||||
BL 37 | Protects the muscles |
ROS ↑ |
I/R + LSTS versus I/R : CK-MM |
Pan et al., 2008 [ |
SO: sphincter of Oddi; NO: nitric oxide; HSP70: heat shock protein 70; LSTS: local somatothermal stimulation; I/R: ischemia-reperfusion; ROS: reactive oxygen species; ALT: alanine aminotransferase; AST: aspartate aminotransferase; CPK: creatine phosphokinase; CK-MB: creatinine kinase-MB isoenzyme; CK-MM: creatine kinase-MM isoenzyme. Reference number is between square brackets.
Several lines of evidence support the idea that NO plays an important role in the gastrointestinal system and acts as a neurotransmitter in nonadrenergic, noncholinergic, or “nitrergic” neurons of the peripheral nervous system [
It is noteworthy that the critical temperature for evoking NO-related sphincteric responses by LSTS is around 42°C, which is similar to the temperature used to induce heat shock protein (HSP) expression in many studies [
Since HSP70 has been reported to enhance myocardial tolerance against I/R injury [
Recently, Pan et al. used the rubber band wrapping model to induce I/R injury to the calf muscle induced via rubber band encasement; the animals underwent injury with or without preconditioning by LSTS. No significant change in neuromuscular function was found between the LSTS (−) and LSTS (+) groups on the first day after I/R injury. However, gait stride length, compound motor action potential, and the level of serum creatine phosphokinase MM isoenzyme were found to be significantly improved on the eighth day when there had been one or two doses of LSTS preconditioning compared to the situation without LSTS preconditioning. The results suggest that LSTS preconditioning protects the animals with respect to neuromuscular plasticity when there is tourniquet-induced neuromuscular injury [
It is well known that viscerovisceral reflex regulation is a normal physiological response. For example, relaxation of the internal sphincter of the anus (the rectoanal reflex) is observed when rectal pressure is increased. A growing body of evidence suggests acupuncture may adjust visceral function and modulate immune response via a “Somatovisceral” mechanism [
Previous investigations have demonstrated that I/R injury of the heart can be attenuated by application of either LSTS or electroacupuncture (EA) at the PC 6 acupoint [
There is consensus that acupuncture evokes complex somatosensory sensations and in this way may modulate the cognitive/affective perception of pain; this suggests that many effects are supported by the brain and various other central nervous system (CNS) networks. Modern neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), have provided a means whereby brain activity in humans can be safely monitored. This type of approach is useful when mapping the neurophysiological correlates of acupuncture [
Different central manifestations between electrical acupuncture and local somatothermal stimulation at peripheral acupoints. Manganese-enhanced functional magnetic resonance imaging was performed in Sprague-Dawley rats after EA (a) at acupoint LI 4 and LSTS (b) at acupoint GB 24. The results showed that EA induced activation of pain-modulation nuclei such as the periaqueductal grey (PAG); however, in contrast, LSTS did not induce such activation.
In order to elucidate the exact mechanism by which LSTS acts beneath the acupoint, LSTS was applied to the acupoint of animals, and the underling muscles were then collected at various time intervals after LSTS, namely, at baseline and at 5 min, 15 min, 30 min, and 60 min after baseline. The time-dependent profiles for free radical production and enzymatic scavenging activity were measured. The concentrations of reactive oxygen species, NO metabolites, and malondialdehyde were found to have increased significantly at 5 min after LSTS, whereas scavenging activity was reduced to its lowest level at 5 min (dismutase) and at 15 min (catalase and glutathione) after LSTS. Expression of HSP70 was significantly lower after LSTS when the animals were treated with an NO synthase inhibitor than in the control group without inhibitor. These results suggest that LSTS induces oxidative stress and a scavenging response in the underlying skeletal muscle and that this plays an initial role in the LSTS-induced Somatovisceral regulation mediated by the heat-sensory afferent loop [
It should be noted that LSTS alone at the LR 14 and PC 6 acupoints induces an elevation in serum ALT/AST [
When the traditional moxibustion technique is carried out, many herbs, including
Previously, the anti-inflammatory effects of moxa smoke on NO production were demonstrated by Matsumoto H et al. using mouse macrophage-like Raw 264.7 cells. This study showed that the 50% inhibitory concentration (IC50) of lipopolysaccharide-induced NO production by moxa smoke (0.16%) was one order of magnitude lower than the 50% cytotoxic concentration (CC50) (4.67%). The inhibition of NO production by moxa smoke is probably due to both an inhibition of iNOS expression and an inhibition of radical scavenging activity [
It is reasonable to speculate that direct moxibustion with a traditional moxa stick may produce its therapeutic effects via thermal action, while traditional indirect moxibustion may act by producing both modest thermal activation and a sympathetic vibration at the skin surface [
Although traditional moxibustion has potential as a treatment, it is not entirely risk free, and several kinds of adverse events have been reported, including trauma [
There is consensus that the expression of HSPs by prior sublethal hyperthermic preconditioning is able to attenuate the heat-induced cellular responses to a subsequent severe heat challenge [
Moxibustion is an ancient Chinese medical technique. The possible mechanisms by which moxibustion may work include temperature-related factors and nontemperature-related factors; the latter include smoke effects, herbal effects and biophysical effects (far infrared). Compared with whole-body hyperthermia or brief ischemia preconditioning, LSTS (an alternative to moxibustion that avoids skin damage) is an easily applicable preconditioning method for the prevention or treatment of overwhelming subsequent I/R injury. However, evidence-based studies of the efficacy of LSTS as well as safety studies are needed using large-scaled clinical trials in order that this ancient Chinese technique can pass muster with Western scientists.
This work was supported by Grants from the National Science Council, Taiwan (NSC 95-2320-B-010-044-MY3, NSC 97-2627-B-010-008-, NSC 98-2320-B-010-012-MY3, and NSC 101-2320-B-010-051-MY3).