Effect of emodin on acute lung injury: a meta-analysis of preclinical trials

Emodin has protective effects on acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). This meta-analysis intended to illustrate the efficacy of emodin on ALI/ARDS animal models.

Relevant preclinical studies were searched on PubMed, EMBASE, and Web of Science. Standardized mean differences (SMDs) with corresponding confidence intervals (CIs) were used to compare lung injury scores, lung wet-to-dry weight ratios (W/D), myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-18, PaO₂, and PaCO₂ between the treatment and control groups. The article quality was appraised using the SYRCLE tool.

Twenty one studies published between 2014 and 2023 were enrolled. Compared with the control group, emodin significantly reduced lung injury scores (SMD: -3.63; 95% CI: -4.36, -2.90; p < 0.00001), W/D ratios (SMD: -3.23; 95% CI: -4.29, -2.16; p < 0.00001), and MPO levels (SMD: -2.96; 95% CI: -3.92, -1.99; p < 0.00001). Furthermore, emodin downregulated TNF-α (SMD: -3.04; 95% CI: -3.62, -2.47; p < 0.00001), IL-1β (SMD: -3.76; 95% CI: -4.65, -2.87; p < 0.00001), IL-6 (SMD: -3.19; 95% CI: -3.95, -2.43; p < 0.00001), and IL-18 levels (SMD: -4.83; 95% CI: -6.10, -3.57; p < 0.00001). Emodin improved gas exchange dysfunction, increased PaO₂ (SMD: 3.76; 95% CI: 2.41, 5.11; p < 0.00001), and decreased PaCO₂ (SMD: -3.83; 95% CI: -4.90, -2.76; p < 0.00001). Sensitivity analyses and stratified analyses were conducted for outcome measures with heterogeneity.

Emodin treatment can effectively reduce the severity of ALI in animal models. Additional animal investigations and clinical trials involving human subjects are imperative.