The necessity of solar near-infrared protection shown through gene expression changes

Over half of the solar energy reaching the Earth consists of near-infrared, and intensive or long-term solar near-infrared exposure induces photoaging. Despite the prevalence of a variety of ultraviolet protection, such as sunscreen, sunglasses, glasses, and films, that are useful in protecting the skin against ultraviolet exposure, solar visible light and near-infrared cannot be blocked and the necessity to protect against solar near-infrared has not been well investigated.
To investigate the necessity of solar near-infrared protection, I assessed cell viability of human fibroblast cells after near-infrared irradiation simulating solar near-infrared exposure using 2 sets of transparent polycarbonate plates, one to block ultraviolet and the other to block both ultraviolet and near-infrared. Further, DNA microarray and quantitative real-time PCR analysis was performed to assess gene expression levels in a 3-dimensional reconstructed corneal epithelial model.
The cell viability was significantly decreased after near-infrared irradiation in near-infrared treated cells without a protective polycarbonate plate and near-infrared treated cells using the polycarbonate plate that only blocked ultraviolet, whereas both ultraviolet and near-infrared protected cells were not damaged. The results of gene expression changes revealed that solar near-infrared can induce tissue damage.
Since near-infrared cannot be adequately blocked by sunscreen and sunglasses, protection from not only ultraviolet but also near-infrared should be considered to prevent tissue damage.

Dr. Yohei Tanaka

Clinica Tanaka Plastic and Reconstructive Surgery and Anti-aging Center

As one of the leading Plastic Surgeons in Japan, Dr. Tanaka brings with him years of experience and a wealth of knowledge in the fields of Plastic and Reconstructive Surgery, anti-aging, and photobiology. He also possesses a deep understanding of and a well-established knowledge about energy based devices. As well as being the Founder of International Photobiological Society, he is also a member of many Japanese and international institutions and societies. Dr. Tanaka has published over 40 peer-reviewed papers in English on topics ranging from plastic and reconstructive surgery to cancer research in a number of prestigious international journals. Through intensive photobiological research, Dr. Tanaka discovered the various biological effects of water-filtered broad-spectrum near-infrared (1000-1800 nm together with a water-filter that excludes wavelengths 1400-1500 nm) including anti-cancer effects.