A rat model establishment of bronchopulmonary dysplasia-related lung & brain injury within 28 days after birth.

Purpose: Lung injury associated with bronchopulmonary dysplasia (BPD) and its related neurodevelopmental disorders have garnered increasing attention in the context of premature infants. Establishing a reliable animal model is essential for delving into the underlying mechanisms of these conditions.
Methods: Newborn rats were randomly assigned to two groups: the hyperoxia-induced BPD group and the normoxia (NO) group. For the BPD group, they were nurtured in a hyperoxic environment with a high oxygen inspired fraction (0.85) from birth until day 14 within 28 days postnatally. In contrast, the NO group consisted of newborn rats that were nurtured in a normoxic environment with a standard oxygen inspired fraction (0.21) for 28 days postnatally. Various pathological sections of both lung and brain tissues were examined. TUNEL staining, immunofluorescence assays, and functional tests were performed, and the results were meticulously analyzed to assess the impact of hyperoxia environments on the developing organs.
Results: In the newborn rats of the BPD group, a significant reduction in alveolar number coupled with enlargement was observed, alongside severe fibrosis, collagen deposition, and constriction of bronchi and vascular lumens. This was accompanied by an accumulation of inflammatory cells and a marked deterioration in lung function compared to the NO group (P < 0.05). Additionally, a decrease in neuronal count, an increase in neuronal apoptosis, proliferation of neuroglia cells, and demyelination were noted, and poorer performance in the Morris water maze test within the BPD group (P < 0.05).
Conclusion: The BPD-rats model was established successfully. Lung injury in the BPD group evident across the bronchi to the alveoli and pulmonary vessels, which was associated with deteriorated lung function at postnatal day 14. Concurrently, brain injury extended from the cerebral cortex to the hippocampus, which was associated with impaired performance in orientation navigation and spatial probe tests at postnatal day 28.
Competing Interests: Declarations. Ethics approval and consent to participate: All the operations followed the National Institutes of Health Guidelines for the Care and Use of Laboratory Animals and ARRIVE Guidelines pertaining to animal experimentation. The protocol for all animal experiments was approved (2023074) by the Experimental Animal Management and Ethics Committee of the West China Second University Hospital, Sichuan University (Sichuan, China). Consent for publication: Not applicable. Availability of data and material. Competing interests: The authors declare no competing interests.
(© 2024. The Author(s).)