The differential expression of novel circular RNAs in an acute lung injury rat model caused by smoke inhalation

Acute lung injury caused by smoke inhalation is a common severe clinical syndrome. This study aimed to investigate the potential expression of circular RNAs during acute lung injury triggered by smoke inhalation. The acute lung injury rat model was established with smoke inhalation from a self-made smoke generator. The occurrence of acute lung injury was validated by an analysis of the bronchoalveolar lavage fluid and hematoxylin-eosin (HE) staining of lung tissues. Next-generation sequencing and quantitative PCR were performed to identify the differentially expressed circular RNAs associated with acute lung injury that was caused by smoke inhalation. The circular form of the identified RNAs was finally verified by multiple RT-PCR-based assays. The bronchoalveolar lavage fluid (BALF) and lung tissue analysis showed that smoke inhalation successfully induced acute injury in rats, as evidenced by the significantly altered cell numbers, including macrophages, neutrophils, and red blood cells, disrupted cell lining, and increased levels of interleukin-1 beta, tumor necrosis factor-alpha, and IL-8 in lung tissues. Ten significantly differentially expressed circular RNAs were identified with next-generation sequencing and RT-PCR. The circular form of these RNAs was verified by multiple RT-PCR-based assays. In conclusion, the identified circular RNAs were prevalently and differentially expressed in rat lungs after acute lung injury caused by smoke inhalation.