Red light-emitting diode therapy minimizes the functional deleterious effects of the antiretroviral ritonavir on osteoblasts in vitro

Long-term human immunodeficiency virus (HIV)-infected patients are considered at higher risk for osteoporosis. Among the various causes that lead these patients to lower bone health, there is the use of antiretroviral drugs (ARVs), especially protease inhibitors (PI), such as ritonavir (RTV). In this context, emerge the potential benefits of LED therapy, whose effects on bone cells are currently being extensively studied, showing a modulation in cell differentiation. However, it remains unclear if photobiostimulation might interfere with RTV effects on osteoblast differentiation.

In the present study, we investigated the effects of red LED (625 nm) irradiation (15 mW/cm², 0.2 J/cm², and 8 mW/cm², 0.12 J/cm²) on osteoblast cell line MC3T3-E1 treated with RTV (2.5, 5, and 10 μg/mL).

Our results indicated that red LED irradiation was able to reverse, or at least minimize, the deleterious effects of RTV on the osteoblasts. Neither the ARV treatments 5 and 10 μg/mL (104.4% and 95.01%) nor the LED protocols (100.3% and 105.7%) statistically altered cell viability, assessed by the MTT assay. Also, the alkaline phosphatase activity and mineralization showed a decrease in osteoblast activity followed by ARV exposure (39.3–73%), which was attenuated by LED in more than 70% with statistical significance (p < 0.05).

In conclusion, photobiostimulation with red LED at 625 nm was associated with improved beneficial biological effects as a potential inducer of osteogenic activity on RTV-affected cells. This is the first study that investigated the benefits of red LED irradiation over ARV-treated in vitro osteoblasts.