A cutting-edge microscope has allowed scientists to capture in real time how electroacupuncture directs the movement of immune cells inside living mice, offering a direct window into the biological mechanisms behind the therapy.

The high-resolution mesoscale microscope called RUSH3D-HR was used to observe how thousands of immune cells swarmed to sites of induced inflammation in the mouse spleen.

When electroacupuncture was applied to a specific acupoint below the knee, the cellular stampede was visibly suppressed, providing vivid, real-time evidence of acupuncture’s anti-inflammatory power.

The system could allow scientists to study complex biological processes in live animals over long periods with less tissue damage than previous methods, helping boost understanding of immune response, disease progression and potential treatments.

“Millions of cells and organelles in mammals continuously migrate, interact and orchestrate to form sophisticated populational dynamics that drive diverse functionalities in different physiological or pathological states,” a research team from Tsinghua University, Tongji Hospital and Zhejiang Hehu Technology said.

The team published their findings in a paper in the peer-reviewed journal Nature Biotechnology on July 15.

Capturing live cellular dynamics with conventional microscopy was challenging due to trade-offs in resolution, field of view, imaging speed and tissue impact, such as phototoxicity, or damage caused by the lights used in the process, the team said.

To balance those trade-offs, the researchers turned to a mesoscale microscope to enable rapid 3D imaging with a wide field of view and subcellular resolution.

Mesoscale imaging bridges the gap between traditional microscopy and macroscopic observations, as it can capture both cellular details and large-scale cell movements.

RUSH3D-HR is an upgraded high-resolution version of the Tsinghua University team’s microscope listed among the top Chinese discoveries of 2024, which they have coupled with an artificial intelligence processing pipeline to capture real-time imaging of complex biological processes.

Using their system, the team captured a specific behaviour of immune cells under inflammatory conditions for the first time and verified the impact of electroacupuncture on reducing inflammation in mice.

The study “demonstrates that Chinese scientists can clearly explain the therapeutic mechanism of acupuncture using internationally recognised scientific research methods, which is a vindication of the scientific validity of traditional Chinese medicine”, Wang Wei, a professor and doctor at Tongji Hospital, told China Science Daily, a publication run by the Chinese Academy of Sciences, on July 15.

The development of mesoscale intravital or live-animal fluorescence has enabled the study of cellular interactions in their native states.

However, the researchers said the progression of diseases required more complex systems that posed an “engineering challenge”.

Unlike prior mesoscale systems that struggled with optical defects, background contamination and phototoxicity, RUSH3D-HR is able to address those challenges with several engineering advances, including a custom-engineered objective lens called Kunlun.

The team tested their system for diverse applications within live mice to demonstrate the system’s “versatility and robustness”.

This included long-term imaging of mouse skin over several hours to observe long-distance collective cell migrations that occur during wound healing.

In mice with induced acute liver failure, the team observed subcellular interactions between the neutrophils and macrophages – both immune cells.

They even observed the increased generation of migrasomes, which are involved in immune response and intercellular signalling during disease progression.

This showed that their system was capable of “efficient discovery of rare immune events in a single trial and greatly reducing the number of animals required for in vivo experiments”.

Notably, the team observed neutrophils exhibiting a behaviour called swarming, in which immune cells migrate in dense clusters in response to inflammatory cues.

While this behaviour is known to be important for rapid immune responses, it has mostly been studied in laboratory settings and not directly in live, whole-animal organs until now.

“Hour-long monitoring [of] over 6,000 neutrophils reveals transient emergent swarming behaviours in mouse spleen” during induced inflammation, the team said.

The researchers said previous studies suggested electroacupuncture at the Zusanli, or ST36, acupoint could have anti-inflammatory effects. Zusanli is a spot below the knee joint and one of the most widely used acupoints in traditional Chinese medicine.

However, they said a lack of high-resolution 3D mesoscale imaging had limited direct assessment of its impact on immune behaviours.

Acupuncture has been used in China for thousands of years, and in the 1950s, the Chinese government institutionalised the practice.

In recent years, there has been growing scientific evidence that supports the efficacy of acupuncture to treat certain conditions, though the theories behind it – such as the concept of qi or life force – still receive pushback.

“We validated that electroacupuncture at ST36 effectively suppressed inflammation, providing direct evidence of peripheral immunomodulation,” the team said.

“As a direct control, we applied acupuncture without electrical stimulation, which did not reduce swarming, and inflammatory activity remained elevated.”

The team said their findings showed that neutrophil swarming could be used as a mesoscale biomarker to test the anti-inflammatory effects of medical interventions.

“This in vivo biomarker responds within hours rather than days and allows direct visualisation of collective subcellular dynamics during early-disease progression,” they added.

“More broadly, RUSH3D-HR provides a powerful platform for monitoring therapeutic responses and validating treatment effects in vivo and is expected to be applied to a wider range of diseases, such as immune disorders, neurological diseases and cardiovascular conditions.”