Objective To explore the mechanisms of crocin against glycocalyx damage and inflammatory injury in lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) mice and LPS-stimulated human umbilical vein endothelial cells (HUVECs). Methods Mice were randomly divided into control, LPS, and crocin + LPS (15, 30, and 60 mg/kg) groups. HUVECs were separated into eight groups: control, crocin, matrix metalloproteinase 9 inhibitor (MMP-9 inhib), cathepsin L inhibitor (CTL inhib), LPS, MMP-9 inhib + LPS, CTL inhib + LPS, and crocin + LPS. The potential cytotoxic effect of crocin on HUVECs was mainly evaluated through methylthiazolyldiphenyl-tetrazolium bromide assay. Histological changes were assessed via hemotoxylin and eosin staining. Lung capillary permeability was detected on the basis of wet-dry ratio and through fluorescein isothiocyanate-albumin assay. Then, protein levels were detected through Western blot analysis, immunohistochemical staining, and immunofluorescence. Results This study showed that crocin can improve the pulmonary vascular permeability in mice with LPS-induced ARDS and inhibit the inflammatory signaling pathways of high mobility group box, nuclear factor κB, and mitogen-activated protein kinase in vivo and in vitro. Crocin also protected against the degradation of endothelial glycocalyx heparan sulfate and syndecan-4 by inhibiting the expressions of CTL, heparanase, and MMP-9 in vivo and in vitro. Overall, this study revealed the protective effects of crocin on LPS-induced ARDS and elaborated their underlying mechanism. Conclusion Crocin alleviated LPS-induced ARDS by protecting against glycocalyx damage and suppressing inflammatory signaling pathways.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Aims: Cold atmospheric plasma (CAP) interacted with tissue and had potential effects on wound healing and tissue regeneration. The aim of this study is to investigate the efficacy and safety of CAP as a novel therapy for diabetic wounds in vitro and in vivo. Methods: The plasma consists of ionized helium gas that is produced by a high-voltage (8.5kV) and high-frequency (17kHz) power supply. Eight-week-old male db/db mice were treated with conventional wound dressing only (control group), additional 90’s CAP (low-dose group) or 180’s CAP (high-dose group) for 2 weeks, respectively. Skin samples around wound in 3, 7, 14 days and blood samples were collected and analyzed in three groups. We carried out in vitro analysis included scratch wound healing assays in immortalized human epidermal HaCaT cells. Results: After 14 days of treatment, CAP could obviously promote diabetic wound healing because of inflammation inhibition and angiogenesis increase. Wound- closure rates of two CAP groups were significantly faster than that of control group. The protein expression of IL-6, TNF-α, iNOS and SOD significantly decreased while the protein level of VEGF, TGF-β in two CAP groups significantly increased compared to those in control group (all p < 0.05). And such changes showed a good consistency with the change in mRNA level (all p < 0.05). In vitro, scratch wound healing assays showed that plasma treatment could effectively accelerate the wound healing within 3 minutes exposure (all p < 0.05). Additionally, there were no significant differences in histological observation and the level of serum ALT, AST, BUN, CREA and WBC among the three groups. Conclusions: CAP treatment for 3 min daily improves diabetic wound healing by inhibiting inflammation, reducing oxidative stress and enhancing angiogenesis without toxicity to liver and kidney. Disclosure R. He: None. Q. Li: None. M. Yu: None. T. Wang: None. H. Lu: None. J. Lu: None. W. Zhu: None. M. Luo: None. J. Zhang: None. H. Gao: None. W. Xing: None. D. Wang: None. F. Liu: None. Funding National Natural Science Fund of China; Shanghai Science & Technology; Shanghai Municipal Education Commission