Molecular Mechanisms of Zhizhu Kuanzhong Capsule in the Treatment of Co-Morbid Anxiety and Depression of Functional Dyspepsia: Network Pharmacology, Molecular Docking and In Vivo Validation

Objective: ZhiZhu Kuanzhong (ZZKZ) capsule, a Chinese herbal extract, is extensively employed for the clinical management of functional dyspepsia (FD) in China. This study aimed to elucidate the therapeutic efficacy and underlying mechanisms of ZZKZ on the co-morbidity of anxiety and depression of FD. Methods: The FD model was established in Sprague–Dawley rats via neonatal gastric irritation with 0.1% iodoacetamide. Subsequently, FD rats were gavaged with ZZKZ or fluoxetine. Depression-like behaviors were evaluated using the sucrose preference test (SPT) and forced swimming test (FST), while anxiety-like behaviors were assessed via light-dark box (LDB) and open field tests (OFTs). Network pharmacology and molecular docking were conducted to explore the mechanisms of ZZKZ’s action. Hippocampal levels of monoamine neurotransmitters and monoaminergic system components were evaluated by HPLC and RT-qPCR, respectively. Serum concentrations of HPA axis hormones were determined by ELISA. Results: ZZKZ administration reversed the deficits in body weight gain and food intake in FD rats. Behaviorally, ZZKZ increased sucrose consumption in SPT and prolonged swimming duration in FST, and it increased duration and entries into the central zone in OFT. According to the prediction of network pharmacology, ZZKZ treatment elevated hippocampal levels of 5-HT/NE/DA, increased expression of TPH2/TH, and decreased expression of MAOA/SERT in FD rats. Molecular docking further confirmed high-affinity binding between core ingredients of ZZKZ and TPH2/TH/MAOA/SERT. Moreover, ZZKZ administration attenuated the stress-induced elevation of serum CRH/ACTH/CORT. Conclusions: ZZKZ effectively ameliorates the disordered gut–brain interaction and mitigates anxiety-like and depression-like behaviors, which might be modulated by the hippocampal monoaminergic system and hypothalamic–pituitary–adrenal axis response.