This work was supported by the Special Talent Program of Chengdu University of Traditional Chinese Medicine for &#34;Xinglin Scholars and Discipline Talents Research Promotion Plan&#34; (33002324).

This protocol is derived from previously published literature14,15,16,17. Male Sprague Dawley (SD) rats (260-300 g, 8-10 weeks old) were used for the present study. The animal protocol was reviewed and approved by the Management Committee from Chengdu University of Traditional Chinese Medicine (Record No. 2023017). Prior to the experiment, the rats were instructed to fast for 24 h. During the e...

Protocol for Studying Gastrointestinal Dynamics and Drug Effects on Motility

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Gastrointestinal motility is accomplished by a series of precisely coordinated smooth muscle contractions and relaxations. This process involves rhythmic contraction of one group of muscle groups, coordinated contraction of multiple groups, and special propulsive contraction20,21. The occurrence of gastrointestinal motility disorders may be associated with dysfunctions at different levels, such as the central nervous system, autonomic nervous system, enteric nerv...

Gastrointestinal diseases, a prevalent condition, gravely impact human life and health1. Gastrointestinal motility disorder is an important part of functional gastrointestinal diseases, manifesting primarily in debilitating symptoms, delayed gastric emptying, and severe gastric issues2. It can disrupt gastrointestinal coordination, hinder gastric emptying, impact intestinal food intolerance, and even cause functional obstruction in the small or large intestine3. For patients undergoing gastrointestinal surgery, this disorder can directly lead to intestinal failure. Moreover, intestinal disorder is not only related to gastrointestinal diseases but also to the pathogenic factors of various other diseases, such as hepatitis and central nervous system diseases. Intestinal microbial communities play a crucial regulatory role in intestinal physiology, including motility, which subsequently influences colonization within the microbial ecosystem4. As hepatitis B virus infection progresses to chronic hepatitis B, there are varying degrees of changes in the intestinal flora. Modulating the intestinal flora has demonstrated benefits in hepatitis B virus treatment5. Additionally, the central nervous system can influence the intestine and alter its microbial composition. Recent advancements in microflora sequencing technology have uncovered bidirectional interactions between gut microflora and central nervous system function, closely associated with the occurrence and progression of central nervous system diseases6,7.
With the aging of society, the incidence of gastrointestinal motility disorder is escalating, linked to the decline or loss of neuronal function in the enteric nervous system and bowel&#39;s intrinsic innervation8. As our comprehension of gastrointestinal diseases broadens, numerous novel ideas and approaches emerge, potentially leading to novel drug developments. However, many of these ideas are still hypothetical or await positive clinical trial outcomes to materialize9,10. Effective research methods are crucial in overcoming gastrointestinal diseases. In recent years, extensive research has focused on gastrointestinal drugs and motility regulation. Gastrointestinal drugs and gastrointestinal dynamics are inseparable, and many other systemic drugs have varying effects on gastrointestinal dynamics. For instance, non-steroidal anti-inflammatory drugs (NSAIDs) are used for pain and inflammation and slow gastrointestinal movement, heightening peptic ulcer risk11. On the other hand, some antidepressants may affect gastrointestinal motility12. Currently, the main in vitro pharmacological experiment studying the effects of gastrointestinal drugs and other systemic drugs on gastrointestinal motility is the in vitro intestine movement assay13. By simulating physiological conditions, they observe drugs&#39; direct impact on intestinal smooth muscle contraction and relaxation, evaluating their gastrointestinal effects. However, the precise cause of gastrointestinal motility disorders remains unclear, likely a complex interplay of genetic, environmental, dietary, and neuroendocrine factors. Consequently, the treatment of gastrointestinal motility disorders continues to pose significant challenges.
The small intestine, being a crucial site for digestion, absorption, and drug metabolism, holds significance in gastrointestinal function. As a result, the isolated intestinal tube movement test is an essential tool for studying gastrointestinal diseases. This involves preparing and placing the animal&#39;s isolated intestinal tube in a bath, connecting it to an energy exchanger, utilizing a transducer to convert mechanical movements into electrical signals for amplification, and recording by a physiological recorder. Various parameters such as frequency, average amplitude of vibration, tension, and area under the curve can be measured to evaluate the motor function of the intestinal tube. This method offers advantages such as simplicity, economic feasibility, easy control of experimental conditions, minimal influencing factors, high reproducibility, and accurate and reliable results. Moreover, it is particularly useful for investigating the mechanism of drug action. However, there are notable challenges in the operation of the isolated intestinal tube experiment, for example, intestinal activity is difficult to maintain for a long time. To address these issues and draw from experiences in in vitro experiments, this paper will provide a detailed introduction to the key problems in experimental operation and present a valuable reference experimental protocol for studying drugs that regulate gastrointestinal motility.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetylcholine&#160;</td>
			<td>Sigma, USA</td>
			<td>A6625</td>
			<td></td>
		</tr>
		<tr>
			<td>atropine</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>IA06501</td>
			<td></td>
		</tr>
		<tr>
			<td>Barium chloride</td>
			<td>Macklin Biochemical Co.,Ltd.,Shanghai, China</td>
			<td>B861682</td>
			<td></td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A501330</td>
			<td></td>
		</tr>
		<tr>
			<td>D-glucose</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A610219</td>
			<td></td>
		</tr>
		<tr>
			<td>drawing software</td>
			<td>GraphPad Software, San Diego, California, USA</td>
			<td>&#8212;</td>
			<td></td>
		</tr>
		<tr>
			<td>Epinephrine</td>
			<td>Sigma, USA</td>
			<td>E4642</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Xiya Reagent Co., Ltd., Shandong, China</td>
			<td>S3872</td>
			<td></td>
		</tr>
		<tr>
			<td>In vitro tissue perfusion system</td>
			<td>PowerLab, ADInstruments, Australia</td>
			<td>ML0146</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A100395</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A100781</td>
			<td></td>
		</tr>
		<tr>
			<td>LabChart Professional version 8.3&#160;</td>
			<td>ADInstruments, Australia</td>
			<td>&#8212;</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2&#183;6H2O</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A100288</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A100241</td>
			<td></td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Sangon Biotech Co., Ltd., Shanghai, China</td>
			<td>A100865</td>
			<td></td>
		</tr>
		<tr>
			<td>nifedipine</td>
			<td>Macklin Biochemical Co.,Ltd.,Shanghai, China</td>
			<td>N5087</td>
			<td></td>
		</tr>
		<tr>
			<td>statistical analysis software</td>
			<td>GraphPad Software, San Diego, California, USA</td>
			<td>&#8212;</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical sutures</td>
			<td>Johnson, USA</td>
			<td>&#8212;</td>
			<td></td>
		</tr>
	</tbody>
</table>

using an in vitro tissue perfusion system to detect the functional activities of isolated intestinal tubes in real time

Gastrointestinal diseases, which have a high incidence, pose considerable challenges for humans. The small intestine is integral to food and drug digestion and absorption and plays a crucial role in treating these diseases. The intestinal tube movement experiment, a common and essential in vitro method, is utilized to study gastrointestinal dynamics. This includes the preparation of the isolated intestinal tube, as well as the suspension of the prepared intestinal tube in the bath and its connection to a signal detector. This is followed by the recording and analysis of a series of parameters, such as tension, which can be used to assess intestinal motor function, as well as considerations for keeping the intestinal tube active in vitro. The standardized program from sampling to data collection greatly improves the repeatability of the experimental data and ensures the authenticity of the recording of intestinal tension after physiological, pathological, and drug intervention. Here we present the key problems in experimental operation and a valuable reference experimental protocol for studying drugs that regulate gastrointestinal motility.

Author Spotlight: Reliable and Reproducible In Vitro Assessment of Drug Impact on Rat Intestinal Tubes

Using An In Vitro Tissue Perfusion System to Detect the Functional Activities of Isolated Intestinal Tubes in Real Time

We present a method for isolating rat intestinal tubes and assessing the impact of drugs on their tension, frequency, and amplitude in vitro. This method offers a valuable approach for researchers investigating intestinal tubes. The current experimental challenge is maintaining the consistency and the stability of technical methods to ensure reliable and reproducible scientific research outcomes, particularly considering the sensitivity and the variability inherent in biological systems.This protocol offers advantages such as simplicity, economical feasibility, easy control of experimental conditions, minimal influencing factors, high reproducibility, and accurate results.

The first part of the study focuses on the process of separating isolated intestinal tubes from the body and converting them into 2 cm tubes in vitro. This process is illustrated in detail in Figure 1. The second part involves the suspension and standardization of the isolated intestinal tube ring. The success of this process is demonstrated in Figure 2, which shows the automatic rhythmic contraction of a normal tube. Lastly, the study examines the effe...

We present a method for isolating rat intestinal tubes and assessing the impact of drugs on their tension, frequency, and amplitude in vitro. This method offers a valuable approach for researchers investigating intestinal tubes.

Gastrointestinal diseases, which have a high incidence, pose considerable challenges for humans. The small intestine is integral to food and drug ...

using-an-vitro-tissue-perfusion-system-to-detect-functional