Introduction

Drowning is defined as submergence in water and asphyxiation due to water inhalation into the lungs or pure asphyxia, and it is a major global public health and safety issue [1]. The Global Burden of Disease study identified that drowning is one of the most common causes of unintentional death, accounting for approximately 500,000 deaths worldwide each year [2]. Seawater is a hypertonic liquid containing 3.5 % sodium chloride, large amounts of calcium and magnesium salts [3]; hypertonic seawater exerts a strong damaging stimulus on the lungs and alveoli, attracting fluid from pulmonary capillaries into the alveoli to cause hemoconcentration, hypovolemia, and pulmonary edema. In addition, seawater contains abundant microorganisms such as bacteria [4], which can lead to severe secondary infections. During the progression of seawater drowning (SWD), complications such as respiratory tachycardia, hypoxemia, disseminated intravascular coagulation, and acute renal failure may occur, and acute lung injury (ALI) stands out as its most prevalent and life-threatening complication [5]. Due to the lack of effective targeted treatments, SWD-induced ALI (SWD-ALI) has an extremely high early mortality rate, making early and accurate assessment of ALI severity pivotal for guiding clinical intervention and reducing mortality [6]. Traditional methods for establishing SWD-ALI mouse models include Direct Drowning (DD), Nasal Drip (ND), and Neck incision endotracheal injections (NEI), all of which have obvious limitations: DD exhibits a very high mortality rate and substantial individual differences; ND has uncontrollable inhalation dose and poor model stability;NEI requires invasive neck surgery, causes severe systemic inflammatory response, and has a long anesthesia time [7], [8], [9], [10]. Such limitations restrict the in-depth exploration of SWD-ALI pathogenesis and the development of targeted therapeutic drugs.

Computed tomography (CT), such as micro-CT, has the advantages of high sensitivity, rapid detection, and non-invasiveness, and has been widely used in the diagnosis and evaluation of respiratory diseases [11], 12]. Mobile CT enables more convenient bedside evaluation for critically ill patients [13], [14], [15]. However, there is a lack of robust evidence for the establishment of a stable SWD-ALI model via an optimized technique, and whether early micro-CT can accurately assess SWD-ALI severity and guide clinical intervention remains unclear.

The lack of a stable, reproducible SWD-ALI mouse model and the unclear value of early micro-CT in injury assessment are the key bottlenecks restricting SWD-ALI research and clinical translation. Based on the clinical characteristics of seawater inhalation via the upper respiratory tract, we designed the Laryngoscopic Endotracheal Injection (LEI) method for SWD-ALI model establishment, which recapitulates clinical seawater inhalation and circumvents the limitations of traditional methods. We hypothesize that the LEI method can stably establish a SWD-ALI mouse model with moderate mortality and controllable injury severity, and micro-CT enables accurate early identification of the lesion location and severity in SWD-ALI, thus offering a reliable foundation for clinical guidance. The core research questions of this study are: (1) Can the LEI‑based artificial seawater injection establish a stable and reliable SWD-ALI mouse model? (2) Can micro-CT accurately evaluate the degree of lung injury in SWD-ALI mice and provide an early basis for treatment selection?