What is photoaging

Skin photoaging refers to the phenomenon of premature aging of the skin caused by light damage such as ultraviolet (UV) radiation after prolonged exposure to sunlight. It is the main form of exogenous skin aging, which is different from natural aging. Natural aging is mainly caused by physiological changes within the body, while photoaging is mainly caused by external environmental factors.

Reasons for photoaging

1.UVA (Long Wave Ultraviolet): UVA can penetrate the epidermal layer of the skin and reach the dermis layer directly. It can damage collagen and elastin fibers, causing the skin to lose elasticity and develop wrinkles. Moreover, UVA can induce the production of oxygen free radicals, which can damage the DNA, cell membrane, and other biomolecules of cells.

2.UVB (medium wave ultraviolet): UVB mainly acts on the epidermal layer of the skin and can cause acute reactions such as skin redness and sunburn. Long term UVB irradiation can cause DNA damage in epidermal cells, leading to skin cancer and other lesions. At the same time, it can also affect the renewal and repair functions of the epidermis, leading to dry and rough skin, and also participating in the formation of pigmentation during photoaging.

In recent years, research has found that visible light (400-760nm) and infrared light (760nm-1mm) also have a certain effect on skin photoaging. Visible light can penetrate the skin to deeper levels, producing free radicals that affect the metabolism of skin cells. Infrared radiation mainly increases skin temperature through thermal effects, leading to inflammatory reactions and tissue damage, thereby accelerating skin aging.

1.Wrinkles: The wrinkles caused by photoaging are mainly coarse wrinkles, distributed in the forehead, eye area, mouth area and other areas of the face. These wrinkles are deeper and wider than those caused by natural aging. For example, crow's feet become more pronounced under photoaging, as the skin around the eyes is thin and long-term exposure to ultraviolet radiation leads to more severe damage to elastic fibers and collagen.

3.Skin laxity: Due to UV radiation damaging the skin's elastic fibers and collagen, the skin loses its original elasticity and firmness. Manifesting as sagging skin, such as sagging skin on the cheeks and blurred jawline, this is due to the destruction of the facial support structure, and the lack of effective support for soft tissues.

4.Rough skin: Photoaging can cause thickening of the stratum corneum and abnormal replacement of epidermal cells. The surface of the skin becomes uneven, rough to the touch, and loses the smooth texture of normal skin. And the skin's ability to retain moisture decreases, becoming dry.

1.Topical drugs: Retinoic acid drugs are commonly used to treat photoaging, which can promote the renewal of epidermal cells and increase collagen synthesis. For example, vitamin A yogurt cream with a concentration of 0.025% -0.1% can improve skin photoaging symptoms, reduce wrinkles and pigmentation.

2.laser therapy：Non ablative laser can stimulate collagen regeneration in the skin, improving skin texture and color. For example, dot matrix laser stimulates the surrounding skin tissue to repair and regenerate by generating tiny thermal damage areas, thereby reducing wrinkles and tightening the skin. Stripping laser is the process of removing the outer layer of skin tissue to promote skin regeneration. It has a good effect on more severe photoaging skin, but the recovery time is relatively long.

4.Radiofrequency therapy：Radio frequency technology heats the dermis layer of the skin to shrink and reshape collagen, achieving the goal of tightening the skin. Devices such as unipolar and bipolar radiofrequency can effectively improve skin laxity and enhance facial contours.

BALB/c mouse skin photoaging model

model building：

Model 2: UVB radiation+D-galactose

data display

Weight and skin gross changes

Skin pathology