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From a survival perspective, it is hypothesized that leech saliva exhibits certain physiological effects to ensure fast blood-feeding, including analgesia, anesthesia, and anti-inflammation to stay undetected by the host and vasodilatation and anti-hemostasis to ensure a steady, rapid, and sustained blood flow to the feeding site. Many anti-hemostatic compounds have been identified in leech saliva, such as hirudin, calin, and bdellin A. However, no specific substance with direct vasodilatory and anti-inflammatory function has been reported from forest leech saliva. Herein, using activity-guided analysis, prostaglandin E1 (PGE1) was identified for the first time as an efficient molecular tool for forest leech blood sucking. The structure of PGE1 was analyzed by nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectroscopy. PGE1 was found to be primarily distributed in the leech salivary gland (1228.36 ng/g body weight). We also analyzed how forest leech PGE1 affects platelet aggregation, skin vascular permeability, bleeding time, and pain. Results indicated that PGE1 efficiently inhibited platelet aggregation induced by adenosine diphosphate (ADP) (5 μM) with an IC50 of 21.81 ± 2.24 nM. At doses of 10, 100 nM, and 1 μM, PGE1 increased vascular permeability by 1.18, 5.8, and 9.2 times. It also prolonged bleeding time in a concentration-independent manner. In the formalin-induced mouse paw pain model, PGE1 suppressed acute pain. To the best of our knowledge, this is the first report on PGE1 in invertebrates. The functions of PGE1, such as vasodilation, platelet aggregation inhibition, anti-inflammation, and pain alleviation, may facilitate the ingestion of host blood by leeches.

Paraquat (1,1-dichloro-4,4-bipyridine, PQ) is a widely used herbicide in agriculture and with extremely potent toxicity that leads to serious public health problem once misused. By accidental or voluntary ingestion, PQ poisoning results in numerous deaths annually, mainly in developing countries where PQ is more largely used. 2 In oral ingestion cases, the mortality rate is over 90%. 3 PQ poisoning through oral, skin and respiratory tracts contributes to multiple organ failure including lungs, kidneys, liver and nervous system, in which the lung is the primary target organ. 4,5 This phenomenon was attributed to high affinity of PQ to alveolar cells. 6 Therefore, PQ poisonings usually cause acute lung injury and, ultimately, acute respiratory distress syndrome and death. 7 Unfortunately, despite the large volume of studies in the past

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Purpose: To investigate the effect of juglone on LPS induced lung injury in a mouse model and in TC 1cell line.Methods: Edema formation in lungs were measured by determination of lung wet/dry weight. Expressions of various proteins were assessed by western blot assay, while Sirt1 level was assessed using immunohistochemistry. Mice were randomly assigned to nine groups of 10 mice each: normal control, untreated and seven juglone treatment groups. Acute lung injury was induced in mice by injecting LPS (10 mg/kg) via intraperitoneal route (ip). The treatment groups were given 10, 20, 30, 40, 50, 60 and 100 μM of juglone, ip, respectively.Results: The levels of MMP-9, IL-6, IL-1β and iNOS were significantly higher in acute lung injury induced mice compared than the control group (p < 0.05). Treatment of the mice with juglone significantly decreased LPS-induced up-regulation of inflammatory cytokines in a dose-dependentmanner. The production of inflammatory cytokines was almost completely inhibited in the mice treated with 100 mg/kg dose of juglone, while treatment of the LPS-stimulated TC 1 cells with juglone upregulated the expression of Sirt1 mRNA. Down-regulation of Sirt1 expression by siRNA inhibited the effect of juglone on LPS-induced increase in inflammatory cytokine production.Conclusion: Juglone prevents lung injury in mice via up-regulation of Sirt1 expression. Therefore, juglone might be useful for the development of a treatment strategy for lung injury. Keywords: Inflammatory, Sirtuin, Edema, Cytokines, Lung injury, TC 1 lung alveolar epithelial cells, Sirt1