Paper Title
Therapeutic Effect of Complex Gel Containing Humulene in Pm2.5-Induced Skin Injury- A Rat Study

PM2.5 absorbs toxic substances and easily enters the human circulation through the respiratory system. In addition to affecting the respiratory system, exposure to PM2.5 causes skin acnes and inflammation-related damage to skin. Humulene, a sesquiterpene, exhibit anti-inflammatory properties by reducing inflammatory cytokine levels and pro-inflammatory protein expression. In this study, we prepared a complex gel containing humulene, hydroxypropyl methyl group (HPMC), Sanxianjiao (XG) and hyaluronic acid (HA) to treat PM2.5-induced skin injury. The results indicated that the IC50 of PM2.5 was approximately 600 µg/mL. The concentration of PM2.5 larger than 400 µg/mL significantly induced the inflammatory response (increased IL-6 inflammatory levels). The IC50 of humulene was approximately 0.075 mM. Severe impairment in the epidermis and hair follicles and moderate impairment in the dermis were found exposed with PM2.5 and continuous subcutaneous injection of PM2.5. Treatment with complex gel containing 0.375 or 0.75 mM humulene repaired the skin injury in epidermis and dermis, restored injured hair follicles. The gel containing 0.75 mM humulene indicate superior repair effect in PM2.5-injured skin. The findings of the current study indicate the therapeutic effects of humulene against various injures caused by PM2.5 in the epidermis and dermis of skin. Keywords - anti-inflammatory, humulene, hydroxypropyl methyl group, PM2.5