Human chorionic gonadotropin attenuates amyloid-β plaques induced by streptozotocin in the rat brain by affecting cytochrome c-ir neuron density

Synthesis, In Silico, and Biological Evaluation of a Borinic Tryptophan-Derivative That Induces Melatonin-like Amelioration of Cognitive Deficit in Male Rat

Preclinical and clinical evidence supports melatonin and its analogues as potential treatment for diseases involving cognitive deficit such as Alzheimer's disease. In this work, we evaluated by in silico studies a set of boron-containing melatonin analogues on MT1 and MT2 receptors. Then, we synthesized a compound (borolatonin) identified as potent agonist. After chemical characterization, its evaluation in a rat model with cognitive deficit showed that it induced ameliorative effects such as those induced by equimolar administration of melatonin in behavioral tests and in neuronal immunohistochemistry assays. Our results suggest the observed effects are by means of action on the melatonin system. Further studies are required to clarify the mechanism(s) of action, as the beneficial effects on disturbed memory by gonadectomy in male rats are attractive.

Naringin Chelates Excessive Iron and Prevents the Formation of Amyloid-Beta Plaques in the Hippocampus of Iron-Overloaded Mice

Metal chelating agents are antioxidant agents, which decrease the reductive potential and stabilize the oxidized metal ion form. In this study, we evaluated the naringin capacity in chelating iron and preventing amyloid-beta plaque formation in the hippocampus of iron-overloaded mice. Thirty-five NMRI male mice (8-10 weeks old) were provided. The mice were classified into five groups. Iron dextran was administered as i.p. injection (100 mg/kg/day) four times a week for four subsequent weeks. The treated groups received 30 and 60 mg/kg/day naringin for a month. After histological processing, the brain sections were stained with Perls' stain kit for iron spots, and Congo red was used to stain the brain and hippocampus for amyloid-beta plaques. 30 mg/kg/day of naringin was shown to decrease nonheme iron in an efficient manner; iron content in this group decreased to 16.83 ± 0.57 μg/g wet weight, a quantity as low as that observed in the normal saline-receiving group. The nonheme iron content in the mice receiving 60 mg/kg/day of naringin was 20.73 ± 0.65 μg/g wet weight. In addition, Aβ plaque numbers in CA1, CA3, and DG areas of the hippocampus decreased significantly following treatment with 30 or 60 mg/kg/day naringin. Naringin has a strong iron chelation capacity and is able to reduce the formation of amyloid plaques. So it can be useful for neuroprotection and prevention of Alzheimer's disease.

Human Chorionic Gonadotrophin: New Pleiotropic Functions for an "Old" Hormone During Pregnancy

Human chorionic gonadotrophin (hCG) is the first specific molecule synthesized by the embryo. hCG RNA is transcribed as early as the eight-cell stage, and the blastocyst produces the protein before its implantation. hCG in the uterine microenvironment binds with its cognate receptor, luteinizing hormone/choriogonadotropin receptor (LHCGR), on the endometrial surface. This binding stimulates leukemia inhibitory factor (LIF) production and inhibits interleukin-6 (IL-6) production by epithelial cells of the endometrium. These effects ensure essential help in the preparation of the endometrium for initial embryo implantation. hCG also effects angiogenic and immunomodulatory actions as reported in many articles by our laboratories and other ones. By stimulating angiogenesis and vasculogenesis, hCG provides the placenta with an adequate maternal blood supply and optimal embryo nutrition during the invasion of the uterine endometrium. The immunomodulatory properties of hCG are numerous and important for programming maternal immune tolerance toward the embryo. The reported effects of hCG on uterine NK, Treg, and B cells, three major cell populations for the maintenance of pregnancy, demonstrate the role of this embryonic signal as a crucial immune regulator in the course of pregnancy. Human embryo rejection for hCG-related immunological reasons has been studied in different ways, and a sufficient dose of hCG seems to be necessary to maintain maternal tolerance. Different teams have studied the addition of hCG in patients suffering from recurrent miscarriages or implantation failures. hCG could also have a beneficial or a negative impact on autoimmune diseases during pregnancy. In this review, we will discuss the immunological impacts of hCG during pregnancy and if this hormone might be used therapeutically.

Vitamin E therapy prevents the accumulation of congophilic amyloid plaques and neurofibrillary tangles in the hippocampus in a rat model of Alzheimer's disease

OBJECTIVES

Vitamin E may have beneficial effects on oxidative stress and Aβ-associated reactive oxygen species production in Alzheimer's disease. But, the exact role of vitamin E as a treatment for Alzheimer's disease pathogenesis still needs to be studied. Hence, we examined the therapeutic effects of vitamin E on the density of congophilic amyloid plaques and neurofibrillary tangles in rats' hippocampi.

MATERIALS AND METHODS

Wistar rats were randomly assigned to control (no drug treatment), sham scopolamine (3 mg/kg)+saline and Sham scopolamine+sesame oil groups, and three experimental groups that received scopolamine+vitamin E (25, 50, and 100 mg/kg/day) daily for 14 days after scopolamine injection. The rats' brains were collected immediately following transcardial perfusion and fixed in 4% paraformaldehyde. Pathological brain alterations were monitored through Congo red and bielschowsky silver staining.

RESULTS

Scopolamine treatment led to a significant increase in the density of congophilic amyloid plaques and neurofibrillary tangles in the hippocampus. IP injection of vitamin E in three doses (25, 50, and 100 mg/kg/day) significantly reversed the scopolamine-induced increase of the congophilic amyloid plaque density and density of neurofibrillary tangles in the hippocampus. Although vitamin E (25 and 50 mg/kg/day) doses were also effective, but a 100 mg/kg/day dose of vitamin E was more effective in the reduction of congophilic amyloid plaque and neurofibrillary tangle density.

CONCLUSION

Vitamin E could exert a therapeutic effect in the reduction of congophilic amyloid plaque and neurofibrillary tangle density in the hippocampus of scopolamine-treated rats and it is useful for Alzheimer's disease.