The Effect of Intranasal Administration of Gangliosides on the Viability of CA1 Hippocampal Neurons in Rat Two-Vessel Occlusion Model of Forebrain Ischemia/Reperfusion Injury.

Intranasal administration of total bovine brain gangliosides (6 mg/kg) to rats protected the CA1 hippocampal neurons from the death caused by two-vessel occlusion model (with hypotension) of forebrain ischemia/reperfusion injury. The immunohistochemical reaction of specific antibodies to marker proteins of activated microglia (Iba1) and astrocytes (GFAP) in hippocampal slices revealed the neuroprotective effect of exogenous gangliosides which can be mostly explained by their ability to suppress neuroinflammation and gliosis. The expression of neurotrophic factor BDNF in the CA1 region of hippocampus did not differ in sham-operated rats and animals exposed to ischemia/reperfusion. However, the administration of gangliosides increased the BDNF expression in both control and ischemic groups. The intranasal route of administration allows using lower concentrations of gangliosides preventing the death of hippocampal neurons.

Development of Low-Molecular-Weight Allosteric Agonist of Thyroid-Stimulating Hormone Receptor with Thyroidogenic Activity.

To normalize the thyroid status in hypothyroidism caused by resistance to thyroid-stimulating hormone (TSH), low-molecular-weight allosteric agonists of TSH receptor can be used. A new compound ethyl-2-(4-(4-(5-amino-6-(tert-butylcarbamoyl)-2-(methylthio)thieno[2,3-d]-pyrimidine-4-yl)phenyl)-1H-1,2,3-triazol-1-yl) acetate (TPY3m), which stimulated the production of thyroxine when administered to rats (25 mg/kg, i.p.) and also increased the expression of thyroidogenic genes in the cultured FRTL-5 thyrocytes (30 µM) and the rat thyroid gland. The in vitro and in vivo treatment with TPY3m did not lead to a decrease in the expression of the TSH receptor gene in thyrocytes, restoring it under the conditions of receptor hyperactivation by the hormone. This determines the retaining and, in some cases, potentiation of the thyroidogenic effects of TSH (FRTL-5) or thyroliberin (rats) when they are coadministered with TPY3m. TPY3m is a prototype drug for correcting thyroid system functions in subclinical hypothyroidism.

Comparative Study of the Restoring Effect of Metformin, Gonadotropin, and Allosteric Agonist of Luteinizing Hormone Receptor on Spermatogenesis in Male Rats with Streptozotocin-Induced Type 2 Diabetes Mellitus.

We compared the effectiveness of human chorionic gonadotropin (hCG; 5 days, 20 IU/rat/day), allosteric luteinizing hormone receptor agonist TP04 (5 days, 20 mg/kg/day), and metformin (28 days, 120 mg/kg/day) in restoring spermatogenesis in male rats with type 2 diabetes mellitus. hCG and TP04 increased the levels of testosterone and expression of the steroidogenic protein StAR, the number of spermatogenic cells, thickness of the seminal epithelium, and the number and motility of mature sperm that were reduced in diabetic rats, though they did not reduce the number of defective spermatozoa. Metformin had a weak effect on steroidogenesis, but was not inferior to luteinizing hormone receptor agonist by its restorative effect on spermatogenesis and also reduced the number of defective forms of spermatozoa. Thus, the spermatogenesis-restoring effect of metformin and luteinizing hormone receptor agonist in type 2 diabetes mellitus are comparable, despite different mechanisms of action.

Normalization of Testicular Steroidogenesis and Spermatogenesis in Male Rats with Type 2 Diabetes Mellitus under the Conditions of Metformin Therapy.

One of the complications of type 2 diabetes mellitus in men is steroidogenic and spermatogenic dysfunctions. There is evidence of a restoring effect of the antidiabetic drug metformin on them. We studied the effect of MF therapy (4 weeks, 200 mg/kg/day) on the hormonal parameters of the gonad axis and on the morphological characteristics of epididymal spermatozoa in male rats with a severe form of T2DM caused by a high-fat diet and a low-dose streptozotocin. It has been shown that MF therapy, along with the restoration of the metabolic parameters, normalizes the plasma levels of testosterone and leptin and the content of testosterone, its precursors, leptin and its receptors in the testes, and also increases sperm motility, which is reduced in T2DM. This is the result of both the systemic action of MF and its direct effect on testicular cells.

Intranasal Administration of Insulin and Gangliosides Improves Spatial Memory in Rats with Neonatal Type 2 Diabetes Mellitus.

We analyzed the effects of intranasal administration of insulin (0.48 U/rat) and gangliosides (6 mg/kg) on spatial memory in rats with the neonatal model of the type 2 diabetes mellitus. The development of diabetes was verified by the glucose tolerance test. Insulin and gangliosides improved training and reversal training in diabetic rats in a modified version of Morris water maze test and reduced the time of finding the hidden platform. High effectiveness of intranasal administration of gangliosides to animals for the normalization of cognitive functions was shown for the first time. The effects of insulin and gangliosides were similar during training, but during reversal training, gangliosides were more effective. At the same time, intranasally administered insulin, unlike gangliosides, partially normalized glucose tolerance in rats with type 2 diabetes mellitus.

[Features of the changes in lipid peroxidation and activity of Na+/K+-ATPase in the brain of the aged rats in the conditions of two-vessel cerebral ischemia/reperfusion.]

The success of preclinical neuroprotection studies depends on the model used in animal research. The methodological approaches developed on young animals and widely used for modeling cerebral ischemia/reperfusion injury may not be so effective or not suitable for its modeling on senescent animals, which usage is recommended for preclinical trials. The aim of this study was to investigate the age-related features on the effect of brain reperfusion with different duration (1 and 3 h) after 2-vessel forebrain ischemia on the level of lipid peroxidation (LPO) products and on the activity of Na+/K+-ATPase in the cerebral cortex of rats aged 22-24 months. We found a later accumulation of LPO products (3 h instead of 1 h after blood recirculation), specifically triene conjugates and Schiff bases, and a decrease in the activity of Na+/K+-ATPase in the cerebral cortex of aged rats compared to young animals. The data obtained reveal the difference in the molecular and physiological mechanisms of the development of disorders in the brain during ischemia/reperfusion in aged and young animals. The revealed differences in these mechanisms should be consider in developing and testing compounds, which will be further used for the treatment of elderly patients with stroke and ischemic brain damage.

Insulin Increases Viability of Neurons in Rat Cerebral Cortex and Normalizes Bax/Bcl-2 Ratio under Conditions of Oxidative Stress.

We studied the protective effect of insulin in various concentrations and its effect on the Bax/ Bcl-2 ratio in neurons of rat cerebral cortex under conditions of oxidative stress. The protective effect of insulin was dose-dependent within the nanomolar range (1 nM<10 nM<100 nM). Preincubation with insulin in concentrations of 100 nM and 1 µM significantly increased Bcl-2 content in neurons in 5, 30, and 45 min and 1, 2, and 4 h after the start of cell exposure to H2O2. This prooxidant increased the Bax/Bcl-2 ratio in neurons to 141-164% in comparison with the control (100%); preincubation of neurons with insulin returned this ratio to normal.

[THE EFFECT OF HORMONAL STIMULATION OF STERLET (ACIPENSER RUTHENUS L.) ON STEROID LEVELS IN TISSUE INCUBATES].

Sex steroids and corticol levels in Leibovitz's L-15 media samples after incubation of intact female and male sterlet (Acipenser rhutenus L.) tissue fragments and those if fishes treated with a superactive analogue of mammalian luteinising hormone-releasing hormone (LH-RH-A) were compared. 17,20ß,21-trihydroxy-4-pregnen-3-one (20ßS) levels were significantly higher in the media samples after incubation of ovarian follicles taken from females 5 h after treatment with LH-RH-A in comparison with 20ßS levels in intact female samples. 20ßS levels also increased after 1 µM progesterone (P4) adding to the media before incubation of ovarian follicles. Cortisol and testosterone levels in the media samples demonstrated the same tendency. Significant elevation of cortisol levels was observed in the blood serum samples of females 5 h after LH-RH-A treatment. The androgens (testosterone and 11-ketotestosterone) levels after incubation of testicular and liver fragments were high in the media samples in males who had high serum levels of these androgens before hormonal stimulation. Sex steroids and cortisol production was stimulated by P4 adding to the media before incubation of gonad fragments. 20ßS media levels increased after P4 adding before incubation of liver fragments.

[Antiapoptotic effect of gangliosides on PC12 cells exposed to bacterial lipopolysaccharide].

Lipopolysaccharide (LPS) from Escherichia coli of the 0111:B4 serotype was shown to exert the apoptotic effect on PC12 neuronal cells at concentrations of 0.1 and 0.125 mg/ml in DMEM (serum free medium). GD1a and GM1 gangliosides at a concentration of 100 µM were found to raise the PC12 cell viability and decrease the percentage of PC12 cells in the late apoptotic phase after exposure to LPS.

Steroids in the control of reproductive function in fish.

Serum and coelomic fluid sex steroid hormone levels were measured in the sturgeon (Acipenseridae) at the onset of anadromous migration and maturation. Cortisol and testosterone levels in coelomic fluid were lower than in serum; conversely, progesterone levels were higher in coelomic fluid than in blood. Specific androgen and estrogen binding in the cytosol of different parts of the brain and in the gonads of fish were different in the pre-spawning state and after ovulation. Before spawning, the highest levels of specific androgen binding were in the forebrain, where levels decreased significantly after ovulation. Specific estrogen binding in the hypothalamus was significantly higher after maturation and ovulation. Correlations were established between sex steroid concentrations in the blood and levels of specific binding in the brain and gonads.