Feng Xiong, Ruimin Xu, Tongju Li, Jinyu Wang, Qingchuan Hu, Xiaojing Song, Guangjun Wang, Huanhuan Su, Shuyong Jia, Shuyou Wang, Zongxiang Zhu, Weibo Zhang. J Acupunct Meridian Stud 2023;16:101-8. https://doi.org/10.51507/j.jams.2023.16.3.101

In more than half a century, exploring the biological connotation of the meridians was one of the core components of scientific research studies in traditional Chinese medicine (TCM). Based on the previous works of low hydraulic resistance channel (LHRC) along meridians (LHRCM), the differential proteomics between the Alcian blue track (ABT) on LHRC along the conception vessel (CV) and nonmeridians tissue next to the CV were investigated in this study to explore the material basis and biological function of LHRCM. Proteomics based on LC-MS was introduced into the subcutaneous connective tissues (SCT) of ABT along the CV and the adjacent nonmeridian (1cm from the CV). A total of 2328 proteins were identified from ABT along the CV and adjacent nonmeridian based on data-dependent acquisition (DDA) mode. In total, 1970 proteins were quantified based on the SWATH (sequential window acquisition of all theoretical fragment ions) label-free model, and the nonstandard and quantitative methods of MSALL were applied to analyze the data. There were 468 proteins differentially expressed. GO analytic results showed that the differential proteins were of varieties in molecular function and biological process. Most of differential proteins were involved in metabolic process, cellular process, response to hormone, and response to wounding. Further analysis showed that the upregulated differential proteins involved in ATP metabolism (ATP5E, GAPDH), redox reactions (Gpx-3), and Ca²⁺ transmembrane transport (CACNA2D1) were closely related to meridian phenomenon and acupuncture effect. These differential proteins would be potential characteristic proteins of the LHRC along the CV in rats which may be useful to deepen the knowledge on LHRCM.

Interstitial fluid, owing to its similarity to blood components and higher sensitivity and specificity, finds widespread application in disease diagnosis and tumor marker detection. However, collecting interstitial fluid, particularly from the deep subcutaneous connective tissue, remains challenging. • This study aimed to compare three different collection methods - push-pull perfusion, multi-filament nylon thread implantation, and tissue centrifugation - for collecting interstitial fluid from the subcutaneous connective tissue layer of mini-pigs. High-performance ion chromatography was employed to analyze the conventional cation components in the samples and compare ion composition analysis between the different methods. • Results indicated that while the distribution of conventional cations in the interstitial fluid collected by the three methods was generally consistent, there were slight variations in the detection rates and concentrations of different ions. Hence, suitable collection methods should be selected based on the ions or collection sites of interest.

How to improve the drugs bioavailability has always been a hot and difficult topic. Conventional drug delivery methods, such as oral administration and the blood circulation system, suffer from issues such as low targeting efficiency, low bioavailability, and high side effects. Recently, interstitium has gradually been recognized as an important new organ. Interstitial injection allows small molecules to move through interstitial channels with interstitial fluid flow and be transported to organs, providing new possibilities for drug delivery. In this study, using fluorescein sodium as a drug model, we systematically investigated the distribution of the fluorescein sodium in organs and body surface of the rats after ventral midline interstitial channels injection. In addition, we observed the microstructure of the ventral midline interstitial channels of abdominal wall and the effects of channels ligation on fluorescein sodium delivery and target organs, to explore the mechanism of interstitial injection. We found that fluorescein sodium can be efficiently transported to the uterus and ovaries along the ventral midline interstitial channels, and the parallel fibers and interconnected interstitial spaces of the channels facilitate long-distance transport of solutes. Additionally, the blockage of the transmission through those channels had results in a significant decrease in targeted transport efficiency over long distances, a decrease in oestrogen levels, organ coefficients, and body weights in female rats. Therefore, the ventral midline interstitial channels with free fluid flow may be a potential communication pathway between body surface and organs. These findings have significant value in the development of drug delivery.

Real-time dynamic monitoring of acupuncture effects is crucial for elucidating its biological mechanisms, yet traditional histological methods fail to capture transient responses in the live microenvironment. Here, we established a methodological framework based on in vivo laser confocal imaging, enabling high-resolution, real-time observation of morphological changes in local tissues following acupuncture intervention. After intravenous injection of sodium fluorescein in rats, dynamic alterations in microcirculation and extracellular matrix (e.g., collagen fiber arrangement) were tracked during acupuncture. The results demonstrated that this method clearly distinguished immediate (e.g., vasodilation) and delayed (e.g., inflammatory response) tissue reactions induced by acupuncture, with a spatial resolution of 0.5 µm and a temporal resolution of 3.5 fps. Subsequent quantitative analysis enabled objective measurement of morphological parameters. This protocol, described in this study, provides a visualization tool for in vivo studies of acupuncture mechanisms and serves as a technical reference for evaluating the effects of other physical stimuli (e.g., moxibustion).

Objective: This study explores the material basis and biological functions of meridian interstitial channels in mini-pigs proximal to the stomach meridian by analyzing differential proteomics between interstitial channels and adjacent non-interstitial channel tissues. Methods: Liquid chromatography–mass spectrometry (LC-MS) under data-dependent acquisition mode was employed to analyze and identify the proteome of subcutaneous connective tissues along the stomach meridian and adjacent tissues. SWATH MS^ALL method and omicsbean online analysis platforms were used for protein quantification and differential proteomic analysis. Differential proteins were subjected to Gene Ontology annotation and KEGG pathway analysis to understand their functions and biological processes. Combining traditional Chinese meridian theory with modern meridian research, proteins most relevant to meridian functions were selected, and their expression levels were assessed using Western blotting. Results: GO annotation and KEGG pathway analysis revealed differences in molecular functions, biological processes, and metabolic pathways among differential proteins. Most downregulated proteins were enzyme functional proteins involved in amino acid metabolism (GOT1), adenosine nucleotide balance conversion (AK1), and calcium ion-binding processes (ANXA6). Most upregulated proteins were structural proteins in the extracellular matrix—collagen proteins (COL3A1, COL6A1, COL6A3, COL6A6, COL12A1, COL14A1) and proteoglycans (DCN, BGN, FMOD)—involved in influencing and regulating collagen fiber generation and arrangement. Intriguingly, almost all differential proteins were associated with gastrointestinal diseases, implying a pathological correlation of differential proteins in the stomach meridian interstitial channel. Conclusions: The stomach meridian interstitial channels in mini-pigs show 72 differentially expressed proteins compared to adjacent tissues. These differences include the upregulation of structural proteins and downregulation of functional proteins, potentially forming the molecular biological basis for the structural and functional specificity of meridians.