Photobiomodulation with 810 nm Wavelengths Improves Human Sperms' Motility and Viability In Vitro

Enhanced sperm motility is necessary for the successful journey of sperm inside the female genital tract, successful fertilization, and the increased chance of pregnancy.

We investigated the impact of red and near-infrared (NIR) ranges of photobiomodulation (PBM) alone and together on fresh human sperm to validate an optimized PBM protocol that would maximize sperm motility and viability in vitro.

We randomly divided 30 normal human semen samples into 3 different PBM protocols (red, NIR, and red+NIR lasers). Each sample was divided into four subparts, one control group sample and three experimental group samples. Each experimental group received one of the PBM protocols (red, NIR, or red+NIR). Each protocol was adjusted to three energy densities (0.6, 1.2, and 2.4 J/cm2). After exposure to the selected protocol, we determined the percentage of either viable or progressive sperm motility (PSM) and measured the DNA Fragmentation Index (DFI).

The NIR and red+NIR lasers at 2.4 J/cm2 energy density significantly increased PSM after 60 min compared with the control groups [least significant difference (LSD) test, p = 0.023 and p = 0.04, respectively]. Samples treated with the red laser at 0.6 J/cm2 had significantly decreased viability compared with the control group (LSD test, p = 0.003). Samples treated with the red+NIR lasers had significantly decreased viability at 0.6 J/cm2 (p = 0.003), 1.2 J/cm2 (p = 0.001), and 2.4 J/cm2 (p = 0.04) energy densities when compared with the control groups. The NIR laser resulted in no significant difference in sperm viability between the control and experimental groups. At 120 min after exposure, treatment with the red+NIR and red lasers at 2.4 J/cm2 density significantly increased DFI compared to the control groups (LSD test, p = 0.000, p = 0.007).

In this study, sperm motility, viability, and DFI data confirmed the superiority of the NIR laser at 0.6 J/cm2 energy density compared with the red and red+NIR PBM protocols.