Hirudin alleviates acute ischemic stroke by inhibiting NLRP3 inflammasome-mediated neuroinflammation: In vivo and in vitro approaches.

Acute ischemic stroke is a severe condition that a vessel supplying blood to the brain is abruptly blocked mostly due to cerebral thrombosis and embolism. There is a dearth of the effective prevention and early intervention strategies. NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated neuroinflammation plays a crucial role in the pathophysiology of ischemic stroke. Hirudin is a secretion from the salivary glands of the leech Hirudo medicinalis and has a role in regulating inflammation. In this study, hirudin with a dose of 10-40 mg/kg was given to middle cerebral artery occlusion/reperfusion mice. Hirudin markedly constrained cerebral infarct area in a dose-dependent manner, and significantly improved locomotor disability at 40 mg/kg dose. Similar to MCC950, a selective NLRP3 inflammasome inhibitor, hirudin inhibited M1 polarization and promoted M2 polarization. It also strikingly suppressed the ischemia-induced overexpression of NLRP3 and its downstream components, caspase-1, apoptosis-associated speck-like protein (ASC), and interleukin-1ß (IL-1ß). Hirudin and MCC950 equivalently protected viability and death of BV-2 microglia cells against oxygen-glucose deprivation/reperfusion (OGD/R), an in vitro cell model of brain ischemia. Both agents had similar effects in normalizing the OGD/R-evoked aberrant microglial profiles and NLRP3 pathway dysregulation as observed in the mice. These results demonstrated anti-ischemic effects of hirudin and its association with the inhibition of microglial NLRP3 inflammasome-mediated neuroinflammation. Hirudin is a promising agent for the early intervention of acute ischemic stroke.

Composition of Triterpenoids in Inonotus obliquus and Their Anti-Proliferative Activity on Cancer Cell Lines.

The objective of this study was to determine the composition of triterpenoids in the extracts from the inner and outer parts of Inonotus obliquus and to evaluate their anti-proliferative activity against cancer cell lines (HT-29, AGS, MCF-7, and PC3). Inner and outer parts of I. obliquus were extracted with 80% methanol for 24 h. The extract was fractionated by Diaion HP-20 resin to obtain the triterpenoid fraction. Composition of triterpenoids in the fraction was analyzed by HPLC and LC-ESI-MS. Anti-proliferative activity was evaluated by MTT assay against cancer cell lines. Inotodiol and trametenolic acid were major triterpenoids in both of the inner and outer parts of I. obliquus. Inotodiol in triterpenoid fractions from the inner and outer parts of I. obliquus was 153.9 ± 15.4 mg/g (dry basis (db)) and 194.1 ± 11.5 mg/g, respectively. Trametenolic acid in triterpenoid fractions from the inner and outer parts of I. obliquus was 94.5 ± 9.15 mg/g (db) and 106.3 ± 8.23 mg/g, respectively. Triterpenoids in the outer part were significantly higher than those in the inner part. Anti-proliferative activity of the triterpenoid fraction from the outer part against AGS, MCF-7, and PC3 was also significantly higher than that of the inner part.