Search strategies for electronic databases.

Introduction
Intestinal constipation is a substantive global health concern, significantly impairing patient quality of life. An emerging view is that the gut microbiota plays a critical role in intestinal function, and probiotics could offer therapeutic benefits. This study aims to consolidate evidence from randomized controlled trials (RCTs) that assess the effectiveness of probiotics in modulating microbiota and ameliorating symptoms of constipation.
Methods
We will execute a systematic evidence search across Medline (via PubMed), Embase, Cochrane CENTRAL, Web of Science, Scopus, and CINAHL, employing explicit search terms and further reference exploration. Two independent reviewers will ensure study selection and data integrity while assessing methodological quality via the Cochrane Collaboration’s Risk of Bias-2 tool. Our primary goal is to outline changes in microbiota composition, with secondary outcomes addressing symptom relief and stool characteristics. Meta-analyses will adopt a random-effects model to quantify the effects of interventions, supplemented by subgroup analyses and publication bias assessments to fortify the rigor of our findings.
Discussion
This study endeavors to provide a rigorous, synthesized overview of the probiotics interventions evidence for modulating gut microbiota in individuals with intestinal constipation. The insights derived could inform clinical guidelines, nurture the creation of novel constipation management strategies, and direct future research in this field.
Ethics and dissemination
As this study aggregates and analyzes existing data without direct human subject involvement, no ethical approval is required. We will disseminate the study’s findings through scientific forums and seek publication in well-regarded, peer-reviewed journals.
Trial registration
OSF registration number:10.17605/OSF.IO/MEAHT.

引言
肠道便秘是一项全球性的重大公共卫生问题，严重损害患者的生活质量。当前学界新兴观点认为，肠道菌群（gut microbiota）在肠道生理功能中发挥关键调控作用，而益生菌（probiotics）或可提供针对性的治疗获益。本研究旨在整合随机对照试验（randomized controlled trials, RCTs）的相关证据，评估益生菌在调节肠道菌群组成、改善便秘症状方面的临床有效性。

方法
本研究将开展系统文献检索（systematic evidence search），覆盖Medline（通过PubMed）、Embase、Cochrane CENTRAL、Web of Science、Scopus及护理及相关健康文献累积索引（CINAHL）数据库，采用明确的检索式并辅以参考文献追溯筛选。由两名独立的研究者分别完成文献遴选与数据完整性校验，并通过科克伦协作组偏倚风险-2工具（Cochrane Collaboration’s Risk of Bias-2 tool）评估纳入研究的方法学质量。本研究的主要结局指标为肠道菌群组成的变化，次要结局指标则涵盖症状缓解程度与粪便性状改善情况。Meta分析（Meta-analyses）将采用随机效应模型（random-effects model）量化干预措施的效应值，并辅以亚组分析（subgroup analyses）与发表偏倚（publication bias）评估，以强化研究结果的严谨性与可靠性。

讨论
本研究致力于为肠道便秘患者接受益生菌干预以调节肠道菌群的相关证据提供一份严谨的系统性综合综述。本研究所得结论可为临床诊疗指南的制定提供参考依据，助力新型便秘管理策略的开发，并为该领域的未来研究方向提供指引。

伦理与传播
本研究仅对现有数据进行汇总与分析，未直接涉及人体受试者相关研究，因此无需获得伦理审查批准。本研究成果将通过学术论坛进行传播，并计划投稿至声誉良好的同行评议期刊正式发表。

试验注册
OSF注册编号：10.17605/OSF.IO/MEAHT。