Scraping, called Gua Sha in Traditional Chinese medicine (TCM), is one of the unique non-medicinal external therapies of TCM under the guidance of the theory of meridians and acupoints. It involves using a smooth-edged instrument for surface frictioning to intentionally raise transitory petechiae and ecchymosis [
PeriScan PIM II Laser Doppler Perfusion Imager (LDPI; Perimed AB, Jarfalla, Sweden) was used to measure skin perfusion volume. A low power 670 nm wavelength was applied. A medium scanning pattern was used. The image primitive was set as 0.75 mm × 0.75 mm. The image size was set at 40 mm × 40 mm. The apparatus was connected to a PC computer to obtain the blood flow images of the body surface. The laser blood flow image and visual image of the detected areas were measured via LDPI 2.5 Image Software. The blood flow of the body surface was measured by Doppler frequency shifts which is proportional to a blood flow-related variable and is expressed in arbitrary perfusion unit (PU) [
WP-1 type of infrared thermograph with a temperature resolution of 0.08°C was applied for thermal images in our study. Based on the infrared radiation photography, the apparatus was connected to a PC computer to convert thermo energy into temperature. The distributions and changes of body temperature were displayed as colorful images. A 3.41 version image processing software was used to analyze the data obtained from the images.
Scraping stimulation was performed by trained therapists using a buffalo horn scraper and a skin lubricant (Jinlongkang, Beijing Jinlong Kang Er Fu Scraping Cupping Research Institute, Beijing, China) to decrease friction. Scraping was conducted on the erector spinal muscle above the back spine (from C7-T10) along the bladder meridian of the right side. The scraping areas is 6-7 cm in width and 20 cm in length. Infrared thermal images were collected at scraping area from C7 to T7. Laser Doppler images were collected in two areas at the scanning centers of bilateral sides of the back spine (scraping area and non-scraping area at the opposite side) respectively. The areas were 4.5 cm lateral to the spinous process of the 4th thoracic vertebra.
Twenty-three healthy subjects (12 males, 11 females) aged from 20 to 40 years old were enrolled after physical examination. Laboratory room temperature were maintained at 24°C−27°C without direct sunlight, infrared radiation, and indoor/outdoor ventilation.
The subjects were seated in a square stool in the laboratory with their back exposed. Before collecting the infrared temperature images, the subjects were needed to stay calm for 15 min to adapt to the room temperature. Infrared temperature images were collected at a sitting position. Then laser Doppler images of both sides of the selected areas at a prone position. After scraping for 5 min, both infrared temperature images and the laser Doppler images of the above areas mentioned were collected immediately after scraping (0 min), 15 min, 30 min, 60 min, and 90 min after scraping respectively.
For infrared thermal images, the subject sat erectly at a distance of 1.5 m to the infrared thermograph. Then the detected area was determined and fixed with a calibration circle. The thermographic imaging system was input into a PC computer to save the infrared images and thermal images. For laser Doppler imaging, the blood perfusion volume of the selected scraping area on the right back and symmetrical non-scraping area on the left side were collected by laser Doppler imager. The images were processed by LDPI 2.5 imaging software for offline analysis.
Data were all presented as mean ± SD. Statistical analysis was performed using SPSS 17.0 Software. A Student’s
After scraping, all the 23 subjects (100%) reported obviously warm accompanied by slight pain at the scraping area. They all felt relax and comfort after scraping. It was observed that the skin became slightly red, and then subcutaneous hyperaemia and subcutaneous bloody spots were found in the local scraping area.
Significant increase of blood volume was observed in the scraping area compared with the baseline level. PU values were 1.0-fold higher compared with the baseline level (
Blood perfusion volume at different time points in scraping area and non-scraping area (PU), (
PU | Scraping area (right) | Non scraping area (left) | |
---|---|---|---|
Before scraping | |||
immediately | |||
15 min | |||
30 min | |||
60 min | |||
90 min |
Visual image (middle) taken at 5 min after scraping showed that the skin of the scraping area turned apparently red. Laser Doppler images (left, non-scraping side; right, scraping side) showed the blood perfusion volume. Images (a)–(f) were taken at 5 min before scraping, 0 min, 15 min, 30 min, 60 min and 90 min after scraping stimulation, respectively.
Changes of blood perfusion volume in scraping area and non-scraping area. ***
As is shown by infrared thermograph, the skin temperature of the scraping area increased significantly with the average temperature increased more than 1°C. Compared with the skin temperature obtained in the opposite non-scraping area and the scraping area before stimulation, significant increase of skin temperature was observed within 90 minutes after scraping, respectively (
Mean infrared temperature at different time points in the scraping area and non-scraping area (
(°C) | Scraping area (right) | Non scraping area (left) | |
---|---|---|---|
Before scraping | |||
Immediately | |||
15 min | |||
30 min | |||
60 min | |||
90 min |
The infrared thermograph images showed the skin temperature of the right body side (scraping) increased significantly after stimulation. Skin temperature increased in the scraping area and extended onto the opposite side and the neck 15 min after scraping. The local temperature increase lasted about 1 hour. (a)–(f): image otabined at 5 min before scraping, 0, 15, 30, 60, and 90 min after scraping.
Changes of temperature in the scraping area and non-scraping area. **
With regard to the skin temperature and local blood volume obtained within 90 minutes after scraping, a close correlation was noted between skin temperature and the local blood volume in the scraping area (
Correlation analysis between temperature and blood perfusion volume in the scraping area.
Scraping, called Gua Sha in TCM, is one of the physical stimulating therapies. Previous reports indicated that physical therapies such as acupuncture, moxibustion, massage, scraping and cupping basically shared similarities in their functions and mechanisms as they all developed from external stimulating therapies [
Skin, covering the body surface, contains abundant capillaries functioned as the major organ for temperature regulation and body defense. Under normal conditions, the blood volume of microcirculation is in accordance with the metabolism level of the tissues and organs to keep a dynamic balance. The capacity and rate of substance exchange of external and internal capillary mainly depended on the open volume and permeability of the true capillary. The present study showed that the the blood flow volume in the scraping area significantly increased, especially immediately after scraping. The values of the blood flow increased 1.0-fold higher in the scraping area than those of the non-scraping area (Table
Generally, the blood circulations in human body surface were stable. Once the pressure and muscle relaxation of scraping extruded subcutaneous capillary, capillary network reconstruction and expansion was induced, which resulted in changes of cutaneous blood volume and skin temperature [
Scraping is performed according to the location of acupuncture points along meridians [
In our study, Laser Doppler and infrared thermal imaging techniques were used for the first time for the detection of the skin temperature and blood volume in healthy subjects. The effect of scraping therapy was analyzed to clarify the mechanism of scraping from microcirculation and energy metabolism. Our study provided theoretical and clinical guidances on the research of meridians and collaterals for further studies. Further studies about the effects of the different scraping techniques on pressure changes of subcutaneous microcirculatory system, and the influences of scraping stimulation on meridians and collaterals should be performed in the near future.
The scientific investigations were supported by funds from national program of the “Eleventh Five-Year Plan” from the Ministry of Science and Technology (2008BAI53B063) to J.-S. Yang. Of the two corresponding authors, B. Zhu designed the experiment and J.-S. Yang has founding support to conduct the study. Q.-Y. Xu performed the experiment, Q.-Y. Xu and X.-Y. Gao constructed the manuscript and L. Yang and Y.-Y. Wang do data analysis and figure managing.