Compound Chaijin Jieyu Fang alleviates insomnia complicated with depression by reshaping actinobacteria to inhibit neuronal apoptosis.

OBJECTIVE: This study aimed to investigate the intervention effect of Compound Chaijin Jieyu Fang (CCJF) on insomnia complicated with depression, focusing on restoring gut microbiota balance, particularly the Actinobacteria, which is implicated in the dysregulation of the tryptophan metabolic pathway. This imbalance contributes to neuronal apoptosis, exacerbating the symptoms of insomnia complicated with depression. METHODS: A Mendelian randomization analysis was conducted to explore the causal relationships between insomnia and depression, as well as the mediating role of gut microbiota. The chemical constituents of CCJF were identified using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A Sleep Deprivation and Chronic Unpredictable Mild Stress (SD + CUMS) rat model was established, and a comprehensive array of methodologies-including behavioral assessments, 16S rRNA sequencing, immunohistochemistry, HE staining, Western blot, ELISA, high-performance liquid chromatography, TUNEL staining, and transmission electron microscopy-was employed to systematically evaluate the effects of CCJF on gut microbiota, tryptophan metabolism, and neurological function. RESULTS: In behavioral experiments, the administration of CCJF notably enhanced sleep quality, cognitive function, and mood state in rats. The CCJF intervention effectively regulated the actinobacteria imbalances, facilitated the production of indole derivatives such as indole-3-acetic acid (IAA) and indole-3-lactic acid (ILA), and activated the aryl hydrocarbon receptor (AhR) pathway. Furthermore, the inhibition of the kynurenine pathway resulted in decreased production of kynurenine 3-monooxygenase (KMO), 3-hydroxykynurenine (3-HK), quinolinic acid (QA), and the NR2B subunit of the N-methyl-d-aspartate (NMDA) receptor. This inhibition contributed to the amelioration of damage to the intestinal barrier and the blood-brain barrier under stress, while also reducing neurotoxicity. Additionally, the intervention promoted the conversion of tryptophan to 5-hydroxytryptamine (5-HT) and melatonin synthesis, and modulated key apoptotic and neurotrophic pathways. These effects collectively reduced neuronal apoptosis, restored synaptic function, and enhanced neuroplasticity. CONCLUSION: CCJF effectively alleviated insomnia complicated with depression by reshaping the actinobacteria, rectifying the shift in the tryptophan metabolic pathway, and attenuating hippocampal neuronal apoptosis. This study provides a new theoretical basis for the study of the mechanism of insomnia complicated with depression and the intervention of traditional Chinese medicine, as well as a potential therapeutic target.