HAMI 3379, a CysLT2R antagonist, dose- and time-dependently attenuates brain injury and inhibits microglial inflammation after focal cerebral ischemia in rats.

Cysteinyl leukotrienes (CysLTs) induce inflammatory responses by activating their receptors, CysLT1R and CysLT2R. We have reported that CysLT2R is involved in neuronal injury, astrocytosis, and microgliosis, and that intracerebroventricular (i.c.v.) injection of the selective CysLT2R antagonist HAMI 3379 protects against acute brain injury after focal cerebral ischemia in rats. In the present study, we clarified features of the protective effect of intraperitoneally-injected HAMI 3379 in rats. We found that HAMI 3379 attenuated the acute brain injury 24 h after middle cerebral artery occlusion (MCAO) with effective doses of 0.1-0.4 mg/kg and a therapeutic window of ∼1h. It attenuated the neurological deficits, and reduced infarct volume, brain edema, and neuronal loss and degeneration 24 and 72h after MCAO. RNA interference with i.c.v. injection of CysLT2R short hairpin RNA (shRNA) attenuated the acute injury as well. Also, HAMI 3379 inhibited release of the cytokines IL-1ß, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) into the serum and cerebrospinal fluid 24h after MCAO. Moreover, HAMI 3379 ameliorated the microglial activation and neutrophil accumulation in the ischemic regions, but did not affect astrocyte proliferation 72h after MCAO. In comparison, the CysLT1R antagonist pranlukast did not affect microglial activation and IFN-γ release, but inhibited astrocyte proliferation and reduced serum IL-4. Thus, we conclude that HAMI 3379 has a protective effect on acute and subacute ischemic brain injury, and attenuates microglia-related inflammation. CysLT2R antagonist(s) alone or in combination with CysLT1R antagonists may be a novel class of therapeutic agents in the treatment of ischemic stroke.

Novel role of human chorionic gonadotropin in differentiation of human cytotrophoblasts.

Our laboratory previously demonstrated that cytotrophoblasts and syncytiotrophoblasts in human placental tissue contain hCG/LH receptors. From this finding, we postulated that one role of hCG might be to promote the differentiation of cytotrophoblasts into syncytiotrophoblasts. To test this postulate, cytotrophoblasts were isolated from human term pregnancy placentas and cultured with and without increasing concentrations of highly purified hCG. The results showed that hCG had a biphasic effect on 1) the aggregation of cells without intervening plasma membranes; 2) the expression of cadherin, a cell adhesion receptor that facilitates cellular aggregation; 3) the expression of hCG/LH receptor gene; and 4) the expression of three different hormonal markers of differentiation. The hCG effects were time and dose dependent and hormone specific. The addition of excess polyclonal hCG antibody, but not normal rabbit serum or nonspecific antirabbit immunoglobulin G, decreased basal responses as well as those to exogenous hCG. The polyclonal hCG/LH receptor antibody increased differentiation and dramatically stimulated hCG secretion in the presence or absence of exogenous hCG. (Bu)2cAMP mimicked the actions of hCG. H-89, a protein kinase-A inhibitor, decreased basal as well as exogenous hCG responses. Calphostin, a protein kinase-C inhibitor and lavendustin, a tyrosine kinase inhibitor, on the other hand, had no effect. In summary, it is novel that hCG made in human placenta can regulate the differentiation of cytotrophoblasts, which make little hCG, into syncytiotrophoblasts, which make considerable amounts of hCG.

[Experimental research of protective and therapeutic effects of zinc and vitamin E on mouse liver radiational damage].

OBJECTIVE: To study the effects of zinc and vitamin E on lipid peroxide (LPO) contents and glutathione peroxidase (GSH-Px) activities in liver homogenates of radiational damage mice. METHODS: Two hundred and forty mice were divided randomly into five groups: normal control group (Group A), 60Co gamma-ray irradiator group (Group B), 60Co + zinc (Zn) group (Group C), 60Co + vitamin E(VE) group (Group D), and 60Co + Zn + VE group (Group E). After irradiated with 60Co gamma-ray 7.5 Gy, the mice were protectively treated with Zn and VE at different times. LPO contents and GSH-Px activities in liver homogenates of the mice were determined. RESULTS: The level of liver LPO was significantly higher (P < 0.01), but the level of liver GSH-Px was significantly lower (P < 0.01) in Group B than those in Group A; the content of liver GSH-Px was markedly higher in Group C and Group D than that in Group B (P < 0.01), while the content of liver LPO was markedly lower in Group D than that in Group B (P < 0.05); the concentration of liver GSH-Px was markedly higher in Group E than that in Group D (P < 0.01). CONCLUSIONS: VE may play an important role in lowering liver LPO contents and raising liver GSH-Px activities in radiational damage mice. vitamin E can cooperate with zinc in raising liver GSH-Px activities, stopping liver cells from lipids peroxidation and keeping integrity of liver cell membrane.