Platelet-rich plasma protects human keratinocytes from UVB-induced apoptosis by attenuating inflammatory responses and endoplasmic reticulum stress.

BACKGROUND: Although the role of platelet-rich plasma (PRP) in ultraviolet light B (UVB)-induced photoaging has been confirmed in many studies, the specific mechanism is still not clear. Therefore, we attempted to investigate the effect and mechanism of PRP on UVB-induced human keratinocyte (HaCaT cells) apoptosis. METHODS: HaCaT cells were collected to construct UVB-induced photoaging models. Then, the cells were divided into Sham group, 5% PRP group, UVB group, and UVB + 5% PRP group. Next, MTT assay was used to detect the level of cell proliferation; flow cytometry to check the level of apoptosis; ELISA to determine the TNF-α, IL-18, IL-6, and IL-1ß levels in the supernatant; and Western blot to test Bax, Bcl-2, cytochrome c (Cyt.c), GRP78, CHOP, and ATF4 protein expression levels. RESULTS: Briefly, 5% PRP intervention could relieve the inhibition of UVB on HaCaT cell proliferation, inhibit the promotion of UVB to cell apoptosis, up-regulate UVB-induced Bcl-2 protein expression, and decrease Bax and Cyt.c protein level. In addition, 5% PRP significantly down-regulated the inflammatory factor levels of TNF-α, IL-18, IL-6, and IL-1ßin UVB-induced cells and reduced the inflammatory response. Moreover, 5% PRP also greatly reduced the protein expression levels of GRP78, CHOP, and ATF4 in UVB-induced cells and alleviated endoplasmic reticulum (ER) stress. CONCLUSION: PRP may protect HaCaT cells from UVB-induced apoptosis by alleviating inflammatory response and ER stress.

Autologous Platelet-Rich Plasma Repairs Burn Wound and Reduces Burn Pain in Rats.

To investigate the effects of autologous platelet-rich plasma (PRP) on burn wound and burn pain in rats. Rats were treated with high-temperature copper rod to induce skin burn. During treatment, the wound area of rats was recorded on days 0, 3, 7, 10, 14 and healing rates were calculated. After 14-day treatment, the paw withdrawal mechanical threshold (PWMT) as well as paw withdrawal thermal latency were measured. In addition, CD31 expression in burn wound was detected by immunohistochemistry. The contents of TNF-α and IL-1ß in wound tissues were detected by ELISA. Moreover, the mRNA and protein expression levels of VEGF, MMP-9, and TGF-ß1 in wound tissues were detected by RT-qPCR together with Western blot. Burn wound of rats in the PRP group gradually got better with a decreased wound area. Compared with the NS group, the wound area of the PRP group was significantly reduced and the healing rate was significantly increased. Meanwhile, PWMT of the rats in the PRP group was obviously increased compared with the NS group. Compared with the NS group, the rate of CD31-positive cells in the wound tissue of burned rats was increased; while the contents of TNF-α and IL-1ß were significantly decreased after a subcutaneous injection of PRP. In addition, the mRNA and protein expression levels of VEGF, MMP-9, and TGF-ß1 in the wound tissue of rats from PRP group were evidently increased. Autologous platelet-rich plasma not only shortened the healing time, but also relieved the burn pain.

Sparks fly between ascorbic acid and iron-based nanozymes: A study on Prussian blue nanoparticles.

Herein we reported Prussian blue nanoparticles (PBNPs) possess ascorbic acid oxidase (AAO)- and ascorbic acid peroxidase (APOD)-like activities, which suppressed the formation of harmful H2O2 and finally inhibited the anti-cancer efficiency of ascorbic acid (AA). This newly revealed correlation between iron and AA could provide new insight for the studies of nanozymes and free radical biology.