PHOTOBIOMODULATION THERAPY REDUCES HYPOXIA-INDUCED LUNG INJURY IN SPRAGUE DAWLEY RATS UNDER HYPOBARIC CONDITIONS

Hypoxia in hypobaric conditions refers to the reduced availability of oxygen due to decreased barometric pressure at high altitudes. As altitude increases, atmospheric pressure decreases, leading to a lower partial pressure of oxygen (PO2) and reduced oxygen saturation in blood and tissues. Photobiomodulation therapy (PBMT) has emerged as a potential adjunctive treatment for lung injury, offering non-invasive and promising benefits. PBMT has shown effectiveness in modulating inflammatory responses, reducing oxidative stress, promoting tissue repair, and improving respiratory function in conditions such as acute respiratory distress syndrome (ARDS), pneumonia, and pulmonary oedema. In this study, thirty 8-week-old male Sprague Dawley rats were divided into six groups: (i) normal control (Normal), no hypobaric exposure or treatment; (ii) negative control (Negative Control), hypobaric treatment without PBMT; (iii) one-week PBMT (PBMT1); (iv) two-week PBMT (PBMT2); (v) three-week PBMT (PBMT3); and (vi) four-week PBMT (PBMT4). Hypobaric exposure was performed weekly for 28 days at the Lakespra Facility (Indonesian Military Air Force, Jakarta, Indonesia) at an altitude of 25,000 feet for five minutes. PBMT was administered every two days with a stimulation energy dose of 0.4 Joule (2.037 J/cm²), totaling 8.15 J/cm² per day. The results indicated that PBMT significantly reduced a lung oedema index, lung injury severity, and expression of IL6, CD73, and adenosine, though it did not consistently reduce HIF-1 expression in lung tissue. In conclusion, PBMT effectively prevented lung injury induced by hypobaric hypoxia.