Predictive models for sensory score and physicochemical composition of Yuezhou Longjing tea using near-infrared spectroscopy and data fusion.

In this study, NIR quantitative prediction model was established for sensory score and physicochemical components of different varieties and quality grades of Yuezhou Longjing tea. Firstly, L, a, b color factors and diffuse reflection spectral data are collected for each sample. Subsequently, the original spectrum is preprocessed. Three techniques for selecting variables, CARS, BOSS, and SPA, were utilized to extract optimal feature bands. Finally, the spectral data extracted from feature bands were fused with L, a and b color factors to build SVR and PLSR prediction models. enabling the rapid non-destructive discrimination of different varieties and grades of Yuezhou Longjing tea. The outcomes demonstrated that BOSS was the best variable selection technique for sensory score and the distinctive caffeine wavelengths, CARS, however, was the best variable selection technique for catechins distinctive wavelengths. Additionally, the middle-level data fusion-based non-linear prediction models greatly outperformed the linear prediction models. For the prediction models of sensory score, catechins, and caffeine, the relative percent deviation (RPD) values were 2.8, 1.6, and 2.6, respectively, suggesting the good predictive ability of the models. In conclusion, evaluating the quality of the five Yuezhou Longjing tea varieties using near-infrared spectroscopy and data fusion have proved as feasible.

Protective effect of L­carnitine against oxidative stress injury in human ovarian granulosa cells.

Granulosa cells (GCs) are important for supporting and nourishing oocytes during follicular development and maturation. Oxidative stress (OS) injury of GCs can lead to decreased responsiveness of follicles to follicular stimulating hormone (FSH), which will accelerate ovarian senescence and adversely affect oocyte and embryo quality. Since L-carnitine has been previously reported to exert strong antioxidant activity, the present study aimed to explore the possible effects of L-carnitine on OS injury and FSH receptor (FSHR) expression in ovarian GCs, results of which may be of significance for GCs protection. In the present study, OS was induced in vitro in KGN cells by treatment with H2O2. KGN cells were cultured and divided into the following four groups: Blank, OS, and 40 and 80 µmol/l L-carnitine pre-treatment groups. In the OS group, cells showed nuclear pyknosis, mitochondria swelled irregularly whilst featuring fractured cristae. In addition, cell viability, ROS levels, superoxide dismutase levels, glutathione levels, malondialdehyde levels, the mitochondrial membrane potential and FSHR expression, as determined by Cell Counting Kit-8 (CCK-8), 2,7-dichloro-dihydrofluorescein diacetate, spectrophotometry, ELISA, spectrophotometry, JC-1 and western blot analyses, respectively, were all significantly different in the OS group compared with those in the control group. However, malonaldehyde levels, reactive oxygen species levels and the apoptosis rate according to flow cytometry were all significantly increased compared with those in the control. Compared with those in the OS group, the morphology of cells and mitochondria in the L-carnitine pre-treatment groups were improved, whilst cell viability and the expression of FSHR were significantly increased but oxidative stress injury was decreased. The present results suggest that L-carnitine can protect the cells from OS damage induced by H2O2, enhance antioxidant activity whilst suppressing the apoptosis of GCs, in addition to preserving FSHR expression in GCs under OS. Therefore, the present study revealed that the introduction of L-carnitine in clinical medicine or dietary supplement may protect GCs, improve follicular quality and female reproductive function.

GC-MS analysis combined with sensory analysis revealed the various aroma characteristics of black tea resulted from different grafting rootstocks.

The study was aim to investigate the effects of grafting on volatile compounds and sensory quality of black tea. Seven groups of black tea were prepared from one nongrafted tea tree "Yinghong9 (YJ)" and six grafted tea trees by grafting scion of "YingHong9" on different rootstocks. Sensory analysis indicated marked/slight variations among seven samples, among which, the one grafting on HuangZhiXiangDanCong (HZX) stood out with floral and fruity aroma. The result of chemometrics analysis suggested various effects on compounds caused by different rootstocks. A total of 38 differential compounds were identified, showing mainly quantitative variations, with 36 being identified in all samples. The significant higher contents of volatiles, such as geraniol, phenylethyl alcohol, (E)-nerolidol, decanal, and linalool oxides, in HZX compared with YJ were observed, which explained why floral and fruity aroma stood out among the whole aroma profile of HZX. Both results of sensory and instrumental analysis suggested certain correlation between compound variations and aroma characteristics. Moreover, different rootstocks influenced the aroma quality in different ways. PRACTICAL APPLICATION: In conclusion, the study illuminates the various effects of grafting on the volatile compounds and aroma quality, which enlightens the possibility of changing aroma quality of black tea by grafting scions on different rootstocks. And thus, it can help guide the practical production when cultivating new varieties.

Non-targeted Metabolomic Analysis Based on Ultra-High-Performance Liquid Chromatography Quadrupole Time-of-Flight Tandem Mass Spectrometry Reveals the Effects of Grafting on Non-volatile Metabolites in Fresh Tea Leaves ( Camellia sinensis L.).

To investigate the effects of grafting on non-volatile metabolites in tea, non-targeted metabolomic analyses of fresh leaves were performed on the basis of ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF/MS). One non-grafted YingHong No. 9 and four grafted tea [grafting scion YingHong No. 9 on four different rootstocks, BaiMao No. 2 (BM2), BaiYeDanCong (BY), HeiYeShuiXian (HY), and WuLingHong (WLH)] were chosen as materials. In total, 32 differential metabolites were identified, including phenolic acids, flavan-3-ols, dimeric catechins, flavonol and flavonol/flavone glycosides, etc. Partial least squares discrimination analysis and hierarchical cluster analysis showed various effects of different rootstocks on metabolites. Thereinto, rootstocks of WLH and BY showed extremely outstanding performance in up- and downregulating these metabolites, respectively. Differential metabolites were enriched into three crucial pathways, including biosynthesis of phenylpropanoids, flavonoid biosynthesis, and flavone and flavonol biosynthesis, which might influence the quality of tea. This study provides a theoretical basis for grafting-related variations of non-volatile metabolites in fresh tea leaves.

Study on the effects of rapid aging technology on the aroma quality of white tea using GC-MS combined with chemometrics: In comparison with natural aged and fresh white tea.

The effects of rapid aging technology on aroma compounds and characteristic of white tea were investigated in comparison with natural aged white tea (NAWT) and fresh white tea (FWT). Volatile compounds of white teas were extracted using headspace-solid phase microextraction (HS-SPME), and analyzed with gas-chromatography-mass spectrometry (GC-MS) coupled with chemometrics. Aroma metabolites analysis showed that 40 compounds were identified to distinguish rapid aged white tea (RAWT) from others. Principal component analysis (PCA), hierarchical cluster analysis (HCA), heatmap analysis and Venn diagram demonstrated that alcohols, aldehydes, ketones, esters, heterocyclics and alkanes exhibited significant variations. Quantitative descriptive analysis of white tea aroma showed that in RAWT, sweet and herbal aroma were significantly improved; whereas grassy green and delicate aroma declined sharply. This study provides a comprehensive investigation on aroma quality of RAWT, offering a potentially rapid way to produce aged white tea.

Study of the aroma formation and transformation during the manufacturing process of oolong tea by solid-phase micro-extraction and gas chromatography-mass spectrometry combined with chemometrics.

Oolong tea is a typical semi-fermented tea and is famous for its unique aroma. The aim of this study was to compare the volatile compounds during manufacturing process to reveal the formation of aroma. In this paper, a method was developed based on head-space solid phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) combined with chemometrics to assess volatile profiles during manufacturing process (fresh leaves, sun-withered leaves, rocked leaves and leaves after de-enzyming). A total of 24 aroma compounds showing significant differences during manufacturing process were identified. Subsequently, according to these aroma compounds, principal component analysis and hierarchical cluster analysis showed that the four samples were clearly distinguished from each other, which suggested that the 24 identified volatile compounds can represent the changes of volatile compounds during the four steps. Additionally, sun-withering, rocking and de-enzyming can influence the variations of volatile compounds in different degree, and we found the changes of volatile compounds in withering step were less than other two manufacturing process, indicating that the characteristic volatile compounds of oolong tea might be mainly formed in rocking stage by biological reactions and de-enzyming stage through thermal chemical transformations rather than withering stage. This study suggested that HS-SPME/GC-MS combined with chemometrics methods is accurate, sensitive, fast and ideal for rapid routine analysis of the aroma compounds changes in oolong teas during manufacturing processing.

Efficacy of moxibustion by stimulating acupoints of Danzhong (CV 17) and Ganshu (BL 18) on hyperplasia of mammary gland in rats.

OBJECTIVE: To evaluate the efficacy of moxibustion, through stimulating acupoints of Danzhong (CV 17) and Ganshu (BL 18) in rats with hyperplasia of mammary gland (HMG) which induced by estrogen and progestogen. METHODS: Thirty female Sprague-Dawley rats were randomly divided into saline control group, HMG model group, and HMG moxibustion group with 10 in each group. Saline control was the group injected by saline. HMG model were created by injection of estrogen and progestogen. Moxibustion group was also injected of estrogen and progestogen with moxibustion at the same time. The Changes of nipple diameter and height were measured. The rats' skin temperature was recorded by an infrared thermal camera at the nipples, mammary areas, Danzhong (CV 17) and Ganshu (BL 18). Pathological changes of mammary gland in rats were also observed under light microscope. RESULTS: The diameter and height of the nipples in model group were prominently bigger and higher than that in control group (P < 0.01). The diameter and height in moxibustion group were prominently smaller and lower than that in model group (P < 0.01), and there was no significant difference between moxibustion group and control group. Compared with control group, skin temperature of the nipples, mammary area, and acupoints Danzhong (CV 17) and Ganshu (BL 18) decreased prominently in model group (P < 0.01-0.05). Compared with model group, skin temperature of that in moxibustion group increased prominently (P < 0.05). CONCLUSION: Treatment with moxibustion can effectively decrease the HMG rats' nipple diameter and height, and increase the skin temperature in HMG model rats at the nipples, mammary areas, Danzhong (CV 17) and Ganshu (BL 18). This study convinces the therapeutic effect of moxibustion on mammary gland hyperplasia.

[How to determine the qi arrival and its strength in clinical research].

Qi arrival is the meridian qi response to acupuncture stimulation. Through analyzing the relevant concepts of qi arrival and summarizing the general understanding of it in clinic and on the basis of the collection of the relevant literature at home and abroad on the determination of qi arrival and its strength, the characteristics are analyzed on the present method and the method for the determination of qi arrival and its strength is discussed in terms of the results in the needling sensation scale. It is believed that the needling sensation and its strength can be used to determine whether the qi is arrived or not and its strength. The components of different types of needling sensation are much better applicable for the analysis on the characteristics and rules on the influence on qi arrival. This method is in compliance not only with the theoretic connotation of qi arrival, but also with the clinical general understanding, which lays the foundation for the analysis on the scale results.

Applications of pain-related evoked potentials and short-latency somatosensory evoked potentials in acupuncture research: a narrative review.

OBJECTIVE: To review and discuss the Chinese and English literature on the use of pain-related evoked potentials (PREP) and short-latency somatosensory EP (SLSEP) in acupuncture research. METHODS: China National Knowledge Infrastructure Database and MEDLINE were searched for the following key words: acupuncture and PREP or SLSEP. RESULTS: Thirty-seven articles were included in the review. Researchers usually use PREPs to study the analgesic effect of acupuncture, observe influential factors, or for mechanistic exploration. In the SLSEP studies, researchers focused on response characteristics of acupuncture, acupoint specificity, and influential factors of the treatment. There were some problems with the study design and conclusions. CONCLUSION: Researchers could use PREP and SLSEP to objectively validate the effects of acupuncture and explore its mechanisms using nerve electrophysiology. Further studies can benefit from observing more acupoints' effects using PREPs or SLSEPs and investigating the placebo effect of acupuncture.

Transcriptional responses and flavor volatiles biosynthesis in methyl jasmonate-treated tea leaves.

BACKGROUND: Tea (Camellia sinensis) has long been consumed worldwide for its amazing flavor and aroma. Methyl jasmonate (MeJA), which acts as an effective elicitor among the plant kingdom, could mostly improve the quality of tea aroma by promoting flavor volatiles in tea leaves. Although a variety of volatile secondary metabolites that contribute to aroma quality have been identified, our understanding of the biosynthetic pathways of these compounds has remained largely incomplete. Therefore, information aboaut the transcriptome of tea leaves and, specifically, details of any changes in gene expression in response to MeJA, is required for a better understanding of the biological mechanisms of MeJA-mediated volatiles biosynthesis. Moreover, MeJA treatment could exaggerate the responses of secondary metabolites and some gene expression which offer a better chance to figure out the mechanism. RESULTS: The results of two-dimensional gas-chromatograph mass-spectrometry showed that the terpenoids content in MeJA-treated tea leaves increased, especially linalool, geraniol, and phenylethyl alcohol. More importantly, we carried out RNA-seq to identify the differentially expressed genes (DEGs) related to volatiles biosynthesis pathways induced by MeJA treatment (0 h, 12 h, 24 h and 48 h) in tea leaves. We identified 19245, 18614, 11890 DEGs respectively in the MeJA_12h, MeJA_24 h and MeJA_48 h samples. The α-Lenolenic acid degradation pathway was firstly responded resulting in activating the JA-pathway inner tea leaves, and the MEP/DOXP pathway significantly exaggerated. Notably, the expression level of jasmonate O-methyltransferase, which is associated with the central JA biosynthesis pathway, was increased by 7.52-fold in MeJA_24 h tea leaves. Moreover, the genes related to the terpenoid backbone biosynthesis pathway showed different expression patterns compared with the untreated leaves. The expression levels of 1-deoxy-D-xylulose-phosphate synthase (DXS), all-trans-nonaprenyl-diphosphate synthase, geranylgeranyl reductase, geranylgeranyl diphosphate synthase (type II), hydroxymethylglutaryl-CoA reductase and 4-hydroxy-3-methylbut-2-enyl diphosphate reductase increased by approximately 2-4-fold. CONCLUSIONS: The results of two-dimension gas-chromatography mass-spectrometry analysis suggested that exogenous application of MeJA could induce the levels of volatile components in tea leaves, especially the geraniol, linalool and its oxides. Moreover, the transcriptome analysis showed increased expression of genes in α-Lenolenic acid degradation pathway which produced massive jasmonic acid and quickly activated holistic JA-pathway inner tea leaves, also the terpenoid backbones biosynthesis pathway was significantly affected after MeJA treatment. In general, MeJA could greatly activate secondary metabolism pathways, especially volatiles. The results will deeply increase our understanding of the volatile metabolites biosynthesis pathways of tea leaves in response to MeJA.

Nontargeted Analysis Using Ultraperformance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry Uncovers the Effects of Harvest Season on the Metabolites and Taste Quality of Tea (Camellia sinensis L.).

The chemical composition and taste quality of tea fluctuate seasonally. However, the compounds responsible for the seasonal variation of metabolic pattern and taste quality are far from clear. This study compared the metabolite profiles of green teas of nine varieties that were plucked in spring, summer, and autumn by using ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) on a reversed phase column. A multivariate analysis indicated distinct differences among the metabolite phenotypes of teas harvested in different seasons. Heat-map analysis and metabolic pathway analysis demonstrated that flavan-3-ols, theasinensins, procyanidins, quercetin-O-glycosides, apigenin-C-glycosides, and amino acids exhibited sharp seasonal fluctuations. An equivalent quantification of tea tastes showed that in summer and autumn teas, the bitterness and astringency were significantly elevated, whereas umami declined. Metabolite content comparisons and partial least-squares analysis suggested that several flavonoids and amino acids are mainly responsible for the seasonal variations in taste quality.

[Our viewpoints on Deqi in the later ages after birth of classical works "The Yellow Emperor's Internal Classic" and "Canon of Difficult Medical Problems"].

In our previous paper, we analyzed "Deqi" in book Huangdi Neijing (The Yellow Emperor's Internal Classic) and Nanjing (Canon of Difficult Medical Problems) from "Zhishen"(Treating mentality) and Tiaoqi (Regulating qi). In the present paper, the authors discuss the connotations of "Deqi" and related events in the later ages of the abovementioned two classic books to the later stage of the Qing Dynasty when involves about 20 classical works as Zhenjiu Dacheng ( The Great Compendium of Acupuncture and Moxibustion), Zhenjing Zhinan (Guide to the classics of Acupuncture), Zhenjiu Daquan (A Complete Works of Acupuncture and Moxibustion) etc. from 1) close association between "Deqi" and patients' mental activity; 2) how to wait for arrival of qi if the needling does not induce "Deqi" for the time being; 3) how to identify "qi-arrival" and then, performing suitable manipulations; 4) Deqi and shallow- or deep-needling; 5) putting more emphasis on patients' feeling and reactions, rather than the practitioners perception beneath the needle which is described in book Huangdi Neijing; and 6) not withdrawing the acupuncture needles if qi does not arrive. Generally, in the later ages, the connotations of Deqi are enriched greatly.

[Analysis on regulating deqi in the ancient works of the late dynasties].

From the time of Neijing (Internal Classic) and Nanjing (Classic of Medical Problems) till the end of Qing dynasty, the medical scholars of each dynasty had taken the recognition of deqi as the subject in the stud- ies. Through the historical analysis, the content of regulating deqi was further understood in relevant ancient liter- ature. By checking the ancient works of acupuncture in each dynasty till the end of Qing dynasty, in reference to the evidences in over 10 works, such as Zhenjiu Dacheng (Great Compendium of Acupuncture and Moxibustion) , Zhenjing Zhinan (Instruction of Acupuncture Canon), Zhenjiu Daquan, and in association with the academic views of acupuncture masters in modern time, it was discovered that the medical scholars after the time of Neijing and Nanjing had enriched the understandings of deqi, such as the connection of cold and heat reaction, radiation to the affected site, reinforcing and reducing purpose in qi regulation. The methods of deqi regulations had, been explored till the end of Qing dynasty since the time of Neijing and Nanjing and the understandings of it were vari- ous among scholars.

Apoptosis, necrosis, and autophagy in mouse intestinal damage after 15-Gy whole body irradiation.

Enterocytes die during high-dose radiation exposure in radiation accidents. The modality of cell death has a profound effect on the therapeutic response. The ilea from mice with 15 Gy total body irradiation (TBI) were drawn, morphological features observed by hematoxylin and eosin staining and transmission electron micrographs. The biochemical features of mouse ileum presented with the structure were cleaved Caspase-3 (apoptosis marker), Light Chain 3 (LC3)-I's conversion to LC3-II (autophagy marker) and high mobility group box chromosomal protein 1's secretion (necrosis marker). Then, the autophagy inhibitor (3-methyladenine), caspase inhibitor (Z-VAD-FMK) or necrosis inhibitor (necrostatin) was used to prevent death. Apoptosis, autophagy and necrosis were all appeared in the ileum, but necrosis had the biggest size; the use of 3-methyladenine and Z-VAD-FMK prolong one day's life of the mice after 15 Gy TBI, necrostatin significantly extended the lifespan of 15 Gy irradiated mice (p < 0.05). The results suggest that the death of enterocytes could not be classified into one type of cell death but rather as 'mixed death.'

[Remarks on the relationship between deqi and effect of acupuncture].

Acupuncturists have always paid high attention to deqi (needling sensation) in clinical. However, relationship between deqi and curative effect has not been elucidated yet. In order to have a further understanding on effect of deqi on clinical effect, through study on literature associated with deqi since the establishment of People's Republic of China in 1949, it is held that various factors can influence therapeutic effect of acupuncture treatment, including whether needling sensation appears or not, the speed of deqi, the intensity of deqi, different types of sensations as well as propagated sensation along meridians (PSM). Joint launched multidisciplinary researches should be carried out to reveal the influence principle of deqi on acupuncture effect, and to lay foundations for the further studies on mechanism of deqi.

Effects of acupuncture applied to sanyinjiao with different stimuli on uterine contraction and microcirculation in rats with dysmenorrhea of cold coagulation syndrome.

In this study, we try to evaluate the effects of acupuncture stimulation with different amounts at Sanyinjiao (SP6) on uterine contraction and uterus microcirculation in rats with dysmenorrhea of cold coagulation syndrome and to explore whether there is direct relativity between "De qi" and needle stimulus intensity. Diestrus female rats were randomly divided into 4 groups, including saline control group, model control group, "A" stimulus group (with strong stimulus), and "B" stimulus group (with weak stimulus). We found that dysmenorrhea rats of the cold coagulation syndrome present a high intensity in uterine tension and high contraction of microvascular diameter. Acupuncture applied with two different stimuli could relieve the symptoms, but, compared with "B" stimulus, "A" stimulus leads to better outcomes on reducing uterine contraction and increasing diameter of uterine microvascular; moreover, hand manipulation during needling mediates the curative effect on the microvascular diameter. Our finding indicates that using thick needles and deep insertion with hand manipulation are more effective and achieve desired level of "De qi" in dysmenorrhea rats.

The Effect of Acupuncture to SP6 on Skin Temperature Changes of SP6 and SP10: An Observation of "Deqi".

Background. Deqi sensation is a complex but an important component for acupuncture effect. In this study, we tried to observe the relationship between Deqi and skin temperature changes and whether there was some relativity between Deqi and needle stimulations on cold congealing and dysmenorrhea rat model. Thirty-two female Sprague Dawley (SD) rats were randomly divided into four groups (Saline Control Group, Model Group, Group A with strong stimulation, and Group B with small stimulation). Group A and Group B were performed with different stimulations. We found that, compared with saline control group, model group, and Group B, Group A showed that the skin temperature changes on right acupoint SP6 and SP10 increased significantly at 5 min-10 min interval. The skin temperature changes on left SP6 decreased at instant-5 min interval. The skin temperature changes on right SP10 decreased significantly at instant-5 min interval and 10 min-20 min interval. Thermogenic action along Spleen Meridian of Foot Greater Yin was manifested as simultaneous skin temperature increase on right SP6 and SP10 at 5 min-10 min interval after needling SP6, which was helpful to illustrate the relationship between the characteristic of Deqi and needle stimulations.

An exploratory survey of deqi sensation from the views and experiences of chinese patients and acupuncturists.

Deqi sensation is believed to be important in clinical efficacy according to TCM theory. The measuring method of Deqi sensation has significant implications for the result of research trials. This study makes an investigation on acupuncture-experienced patients and expert acupuncturists in China and aims to find out the patient's needling sensations and acupuncturist's sensations which can be acceptable as descriptors of Deqi sensation, so as to provide foundation for more systematic and sensitive quantitative evaluation method of Deqi sensation. Results of this survey indicated that the Deqi sensation noted by both patient and acupuncturist is equally important to the treatment efficacy. It is found that there are some differences between the patients' real-life experience and the acupuncturists' expectations on patients' Deqi sensation. The "dull pain," "aching," "sore," "numb," "distended," "heavy," "electric," "throbbing," "warmness," "coolness," "spreading," and "radiating" can be considered as the main manifestations of Deqi sensations. The acupuncturists believed that Deqi sensations were mainly "pulling," "tight," and "throbbing." We suggest developing a questionnaire measuring the Deqi sensations which includes both the sensations of the patient and acupuncturist, and this would be very important and necessary for a better understanding of the relationship between Deqi sensation and acupuncture effects in future studies.

The historical development of deqi concept from classics of traditional chinese medicine to modern research: exploitation of the connotation of deqi in chinese medicine.

Although it is difficult in fully clarifying its mechanisms and effects, Deqi still can be considered as an instant "sign" of acupuncture response of the patient and acupuncturist, which has a significant value in clinic and research. This paper aims to take a history trace to the development of Deqi theory, understand the connotation of Deqi based on Chinese medicine theory, and establish an evaluation methodology accordingly. We believe that Deqi is not only the needling sensation, but also the perception of changes of qi (') flowing of the patient elicited by needling on acupoints. The signs of Deqi include the patient's subjective perception (needling sensation), the objective physiological changes (common referred to the skin redness around the acupoints and the response of brain), and the acupuncturists' perception. Although Deqi is essential for attaining the effect, it may not be the necessary sign of the ideal efficacy. It is found that the characteristics of Deqi sensations, Deqi's intensity, time duration, and the propagation will all affect the efficacy. Thus, acupuncturists should pay attention to elicit and control Deqi state, which is also the key point in modern research on the therapeutic implications of Deqi.

[Review of studies on Deqi of acupuncture mainly in foreign countries].

UNLABELLED: Deqi (needle sensation), is closely related to clinical therapeutic effect of acupuncture in the treatment of different clinical conditions. In the present paper, the authors summarized various components or concepts of Deqi mainly in the foreign studies collected from Pubmed database. At present, foreign researches about Deqi mainly include 1) the subjects' subjective qualitative and quantitative descriptions about Deqi, 2) correlation between acupuncture stimulation induced Deqi and clinical therapeutic effects, and 3) responses of different brain regions or the connectivity of brain network shown by functional magnetic resonance imaging (fMRI) during Deqi by needling different acupoints. According to the current commonly used 6 questionnaires, aching, tingling, numbness, heaviness, dull pain, throbbing, and deep pressure sensation are the most frequently seen components of Deqi of acupuncture stimulation. The factors influencing Deqi are psychological state, personal previous experience and cultural background. Regarding the degree of Deqi and clinical effects or outcomes, the conclusions are controversial. RESULTS: of fMRI analysis shows that in spite of extensive deactivation of the limbic system has been found in many studies, and the connectivity of the intrinsic brain functional networks is increased during acupuncture-induced Deqi, the significance of activation or deactivation of some brain regions remains unclear, and the related mechanisms need to be studied further. No matter activation or deactivation of different brain regions during Deqi, the most important issue is the relationship between Deqi and clinical therapeutic effects. Further studies are definitely needed.