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.

Effect of Different Doses of Radiation on Intestinal Injury in NOD/SCID Mice.

Objective To study the effect of different doses of radiation on intestinal injury,with an attempt to find the optimal radiation dose for establishing intestinal injury models in NOD/SCID mice. Methods Forty healthy male SPF-grade NOD/SCID mice were divided randomly into four groups:blank control group and 4-,5-,6-Gy irradiatio groups,with 10 mice in each group. The irradiation rate was 1 Gy/min. The general conditions,body weight,intestinal bacterial translocation,and histopathologic changes were observed and compared. Results The survival rate was 60%,50%,and 30% in the 4-,5-,and 6-Gy groups 15 days after irradiation,and the intestinal bacterial translocation rate was 20%,50%,and 70%,respectively. The body weights in 5-Gy group (P=0.015) and 6-Gy group (P=0.011) were significantly higher than that in blank control group. The length of small intestinal villi decreased in the 4-Gy group. In the 5-Gy group,the structure of intestinal mucosa villi became wide,flat,and inverted,along with the shedding of epithelial cells,the atrophy of glands,and the damage of recess structures. In the 6-Gy group,the structure of intestinal mucosal villi was damaged,the villi were ruptured and smashed,and the recess structures were missing;meanwhile,there was a large amount of inflammatory cell infiltration between tissues,along with visible spotty bleeding and necrosis. The length of small intestine villi in the blank control group and 4-,5-,and 6-Gy groups were (361.77±22.77),(291.68±32.45),(248.03±51.09),and (195.90±26.39) µm,respectively. In particular,it was significantly shorter in 4-Gy group (P=0.005),5-Gy group (P<0.001),and 6-Gy (P<0.001) than in the blank control group,was significantly shorter in the 5-Gy group (P=0.041) and 6-Gy group (P=0.001) than in the 4-Gy group,and significantly shorter in 6-Gy group than in the 5-Gy group (P=0.020). Conclusion 5-Gy irradiation in mice models can decrease body weight,cause the damage of intestinal mucosa and the shedding of inflammatory cells,with stable survival rate and bacterial translocation rate.

Manganese Superoxide Dismutase Gene-Modified Mesenchymal Stem Cells Attenuate Acute Radiation-Induced Lung Injury.

Radiation-induced lung injury (RILI) is a major clinical complication for radiotherapy in thoracic tumors. An immediate effect of lung irradiation is the generation of reactive oxygen that can produce oxidative damage to DNA, lipids, and proteins resulting in lung cell injury or death. Currently, the medical management of RILI remains supportive. Therefore, there is an urgent need for the development of countermeasures. The present study aimed to evaluate the protective effect of manganese superoxide dismutase (MnSOD) gene-modified mesenchymal stem cells (MSCs) to facilitate the improved recovery of RILI. Here, nonobese diabetic/severe combined immunodeficiency mice received a 13 Gy dose of whole-thorax irradiation, and were then transfused intravenously with MnSOD-MSCs and monitored for 30 days. Lung histopathologic analysis, plasma levels of inflammatory cytokines (interleukin [IL]-1, IL-6, IL-10, and tumor necrosis factor-α), profibrotic factor transforming growth factor-ß1, and the oxidative stress factor (hydroxyproline) were evaluated after MnSOD-MSC transplant. Apoptotic rates were evaluated by terminal deoxynucleotidyl transferase-mediated nick-end labeling immunohistochemical method. Colonization and differentiation of MnSOD-MSCs in the irradiated lung were analyzed by immunofluorescence staining. Consequently, systemic administration of MnSOD-MSCs significantly attenuated lung inflammation, ameliorated lung damage, and protected the lung cells from apoptosis. MnSOD-MSCs could differentiate into epithelial-like cells in vivo. MnSOD-MSCs were effective in modulating RILI in mice and had great potential for accelerating from bench to bedside.