Effect of acupuncture at Back-Shu points on gut microbiota in insomnia model rats based on metagenomic sequencing technology

# Acupuncture and Gut Microbiota: A New Pathway for the Treatment of Insomnia

Insomnia represents one of the most prevalent sleep disorders today, affecting between 11% and 60% of the population over a one-year period. Characterized by difficulty initiating or maintaining sleep, often accompanied by fatigue, depression, and anxiety, this condition can persist for years and significantly impact quality of life. In recent years, scientific evidence has pointed to a fascinating connection between sleep quality and the health of our gut, specifically through the community of microorganisms that inhabit our digestive tract, known as the gut microbiota.

Recent research reveals that people with insomnia often have imbalances in the gut microbiota, with a reduction in beneficial bacteria and lower microbial diversity. This imbalance, called dysbiosis, can compromise the gut barrier, trigger low-grade inflammation, and affect the functioning of the central nervous system through what scientists call the "microbiota-gut-brain axis." While conventional treatments for insomnia depend primarily on sedative medications, which can cause tolerance and unwanted side effects, acupuncture emerges as a promising alternative, offering therapeutic benefits with minimal adverse effects.

This innovative study investigated how acupuncture can improve insomnia by modulating the gut microbiota. The researchers used a well-established experimental model, inducing insomnia in rats by administering para-chlorophenylalanine (PCPA), a substance that depletes brain serotonin and faithfully reproduces the characteristics of human insomnia. Forty rats were divided into four groups: normal control, insomnia model, acupuncture treatment, and estazolam treatment (a conventional medication for insomnia).

The acupuncture protocol followed principles of traditional Chinese medicine, using specific points on the animals' backs known as the Back-Shu points of the five vital organs: heart, liver, spleen, lung, and kidney. These points are traditionally used to regulate organ function and strengthen vital energy. Treatment was applied daily for one week, with needles inserted to a standardized depth and held for fifteen minutes. To objectively assess the effects of treatment, the researchers used behavioral tests that measured the time required to fall asleep and the duration of sleep after administration of sodium pentobarbital.

The results were remarkably promising. Acupuncture demonstrated significant efficacy in improving sleep parameters, substantially reducing the time to fall asleep and prolonging sleep duration compared with the untreated group. Even more striking was the finding that acupuncture promoted a beneficial reorganization of the gut microbiota. Through advanced metagenomic sequencing, which allows analysis of all the genetic material of gut microorganisms, the researchers identified specific changes in microbial composition.

Acupuncture partially restored the microbial diversity that had been compromised by insomnia induction and promoted the growth of beneficial bacteria, particularly Lactobacillus species such as Lactobacillus johnsonii and Ligilactobacillus murinus. These bacteria are known to produce important neuroactive compounds, including short-chain fatty acids and the inhibitory neurotransmitter GABA. Simultaneously, acupuncture suppressed the overgrowth of certain potentially harmful bacteria, such as those of the order Enterobacterales, restoring a healthier balance in the gut ecosystem.

The clinical implications of these findings are profound and open new horizons for the treatment of insomnia. Acupuncture demonstrated not only direct improvement of sleep symptoms but also correction of the underlying microbial imbalances that may perpetuate the disorder. The proposed mechanism involves increased production of short-chain fatty acids by beneficial bacteria, which can strengthen the gut barrier, reduce systemic inflammation, and modulate the activity of the hypothalamic-pituitary-adrenal axis, often hyperactive in insomnia.

For patients suffering from insomnia, these results offer hope for a more holistic therapeutic approach with fewer side effects. Acupuncture may represent a treatment strategy that not only relieves immediate symptoms but also addresses the underlying causes of the disorder through the restoration of gut health. For health care professionals, this study provides robust scientific evidence for the inclusion of acupuncture in treatment protocols for insomnia, especially for patients seeking alternatives to conventional medications or who experience unwanted side effects.

However, it is important to acknowledge the limitations of this research. The study was conducted in an animal model, and although the results are promising, clinical studies in humans are needed to confirm the applicability of these findings. In addition, the study used only male rats, and sex-related differences may influence both the response to acupuncture and the interactions between microbiota and sleep. The observation period was relatively short, limiting our understanding of the long-term effects of treatment.

Another important consideration is that, although the study demonstrated clear correlations between microbiota changes and sleep improvement, the direct causal relationship still needs to be established through additional studies, such as fecal microbiota transplantation or antibiotic depletion. The researchers also relied primarily on metagenomic predictions to infer metabolic changes, and validation through direct biochemical analyses of metabolites such as short-chain fatty acids and neurotransmitters is needed.

Despite these limitations, this study represents a significant advance in understanding the mechanisms by which acupuncture exerts its therapeutic effects on insomnia. By establishing a clear link between acupuncture, modulation of the gut microbiota, and improvement of sleep, the research provides a solid theoretical basis for the development of more personalized and integrated therapies for sleep disorders. The findings suggest that future therapeutic approaches for insomnia could benefit from the combination of acupuncture with microbiota-targeted strategies, such as specific probiotics or dietary modifications, offering patients more effective treatment options with a solid scientific basis.