[Aspirin reduces lung inflammatory response in acute lung injury/acute respiratory distress syndrome: a Meta-analysis based on animal experiments].

Objective: To systematically evaluate the impact of aspirin on the pulmonary inflammatory response in animal models of acute lung injury/acute respiratory distress syndrome (ALI/ARDS).

Methods: Experimental research on aspirin therapy or prevention of ALI/ARDS in animal models were searched in PubMed, Web of Science, Cochrane library, Embase, China biology medicine, CNKI, Wanfang, VIP. The search time limit was from the establishment of the database to July 17, 2023. The control group established the ALI/ARDS model without any pharmacological intervention. The intervention group was given aspirin or aspirin-derived compounds or polymeric-aspirin (Poly-A) at different time points before and after the preparation of the model, of which there was no restriction on the dosage form, dosage, mode of administration, or number of doses. The primary outcome indicators included bronchoalveolar lavage fluid (BALF) or lung tissue myeloperoxidase (MPO) activity, interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and the counts of neutrophils in BALF. Two researchers screened the literature and extracted information based on inclusion and exclusion criteria. Literature quality was assessed by the bias risk assessment tool SYRCLE. RevMan 5.3 software was used for data synthesis and statistical analysis.

Results: A total of 17 papers were eventually included, involving a total of 449 animal models, all of which were murine. One paper was at high risk of bias and the rest 16 papers were at moderate risk of bias. Meta-analysis showed that compared with the control group, the neutrophil count in BALF [standardized mean difference (SMD) = -5.06, 95% confidence interval (95%CI) was -7.00 to -3.12, P < 0.000 01], the myeloperoxidase (MPO) activity in BALF or lung tissue (SMD = -3.45, 95%CI was -4.43 to -2.47, P < 0.000 01), the TNF-α level in BALF or lung tissue (SMD = -2.78, 95%CI was -3.58 to -1.98, P < 0.000 01), and the IL-1β level in BALF or lung tissue (SMD = -3.12, 95%CI was -4.56 to -1.69, P < 0.000 1) were significantly decreased in the ALI/ARDS model of the intervention group.

Conclusions: Aspirin reduces the level of lung inflammation in animal models of ALI/ARDS. However, there are problems of poor quality and significant heterogeneity of the included studies, which still need our further validation.