Effect of Zhizhu Kuanzhong capsule on functional dyspepsia: Protocol for a systematic review and meta-analysis of randomized controlled trials

Zhizhu Kuanzhong, a traditional Chinese medicine, alleviates gastric hypersensitivity and motor dysfunction on a rat model of functional dyspepsia

Ethnopharmacological relevance: Zhizhu Kuanzhong (ZZKZ) is a traditional Chinese medicine modified from classic formula Zhizhu decoction in "Synopsis of Golden Chamber" (Han Dynasty in the 3rd century) and the Zhizhu pill in "Differentiation on Endogenous" in Jin Dynasty (1,115-1,234). ZZKZ contains four botanical drugs, including Citrus × Aurantium L [Rutaceae; Aurantii Fructus Immaturus], Atractylodes Macrocephala Koidz. [Compositae; Rhizoma Atractylodis Macrocephalae], Bupleurum Chinense DC [Apiaceae; Radix Bupleuri Chinensis], and Crataegus Pinnatifida Bunge [Rosaceae; Fructus Crataegi Pinnatifidae], which have been widely used in clinical therapy for functional dyspepsia (FD). Aim of the study: This study aimed to evaluate the pharmacological effects and mechanisms of action of ZZKZ on gastric hypersensitivity and motor dysfunction in a rat model of FD. Materials and methods: FD was induced in Sprague-Dawley rats by neonatal gastric irritation with 0.1% iodoacetamide. The FD rats were treated with ZZKZ (0.5 g/kg, 1.0 g/kg, or 1.5 g/kg respectively) by gavage for 7 days, while domperidone (3 mg/kg) acted as treatment control. Body weight gain, food intake, gastric emptying, and intestinal propulsion were also measured. Ex vivo gastric smooth muscle activity recordings and greater splanchnic afferent (GSN) firing recordings were employed to evaluate gastric motility and sensation. Particularly, the role of 5-HT in the action of ZZKZ in improving gastric dysmotility and hypersensitivity was explored. Results: ZZKZ promoted weight gain, food intake, gastric emptying, and intestinal propulsion in FD rats. ZZKZ promoted spontaneous and ACh-induced contractions of gastric smooth muscle strips in FD rats, alleviated spontaneous activity, and chemical (acid perfusion) and mechanical (intragastric distension) stimulated GSN firing in FD rats. ZZKZ ameliorated gastric smooth muscle contraction and GSN firing induced by 5-HT in FD rats. ZZKZ stimulated the release of serum 5-HT, with reduced 5-HT3 receptor and increased 5-HT4 receptor mRNA expression in the guts of FD rats. Conclusion: This study demonstrated that ZZKZ improves FD-related gastric hypersensitivity and motor dysfunction and should be an effective compound for relieving FD symptoms. The gastric 5-HT system with lower 5-HT3 activity and increased 5-HT4 distribution is involved in the mechanisms of ZZKZ underlying the treatment of FD.

Complementary and alternative medicine for functional dyspepsia: An Asian perspective

A considerable number of Asian patients with functional dyspepsia (FD) are searching for complementary and alternative medicine (CAM) because they are unsatisfied with conventional medical treatment. However, no article has focused on CAM for FD from Asian perspective. In Asian countries, many traditional herbal formulas, including Banha-sasim-tang, Soyo-san, Sihosogan-san, Yukgunja-tang, and Pyeongwi-san, are used in patients with FD. In the few blinded and placebo-controlled studies conducted, the weak evidence regarding the effectiveness of herbal prescriptions in patients with FD did not allow any conclusions to be made. The clinical efficacy and safety of STW-5 were proven in several prospective randomized controlled trials and systematic reviews. Hence, it was recently approved as a therapeutic option for the treatment of FD. Peppermint and caraway, FDgard, black seed oil, and Jollab have been used in patients with FD, but there is limited evidence supporting their use. Reviews of acupuncture in patients with FD showed inconsistent results: a Cochrane review reported a negative result, while other meta-analyses reported positive results. Psychotherapy, including hypnotherapy, psychoanalytic psychotherapy, and cognitive behavioral therapy, may be used in patients with FD, although it is only supported by weak evidence. Therefore, well-planned, large-scale studies are necessary to evaluate the efficacy of CAM in treating FD, especially in Asian countries.