Photobiomodulation therapy enhances surfactant production in premature rat lungs: a non-invasive therapeutic strategy for neonatal respiratory distress syndromes.

Summary

In preterm rats, 660 nm photobiomodulation (30 mW, 3 J/cm², thrice daily for 3 days) significantly increased surfactant proteins B, C, and D without cytotoxic or phototoxic damage. The 830 nm regimen showed variable surfactant increases with minimal cytotoxic effects, supporting 660 nm PBM as a promising noninvasive modality for neonatal respiratory distress syndromes.

Key Findings

• Preterm rat model (n=68) showed significant increases in surfactant proteins B, C, and D with 660 nm PBM (30 mW, 3 J/cm², three times daily for 3 days).
• No evidence of cytotoxic or phototoxic damage with 660 nm PBM; 830 nm showed variable surfactant increases and minimal cytotoxic effects.
• Histology and ELISA confirmed enhanced surfactant production, with supportive in vitro cytotoxicity/genotoxicity assessments.

Clinical Implications

If validated in humans, 660 nm PBM could serve as an adjunct to improve surfactant sufficiency in neonatal respiratory distress syndrome, potentially reducing the need for exogenous surfactant or invasive ventilation.

Limitations

• Preclinical animal study with short follow-up (3 days) limits generalizability to human neonates.
• Mechanistic pathways underlying surfactant increase (e.g., AT2 cell signaling) not fully delineated.

Future Directions

Conduct dose-ranging and sham-controlled neonatal clinical trials, define optimal PBM parameters, and elucidate cellular signaling pathways driving surfactant upregulation.