Depression is a complex, heterogeneous and multifactorial disease with poorly understood pathophysiological mechanisms. Outbred Sprague Dawley (SD) and Wistar Han (WH) rats are widely used in biomedical research, in particular, in the model of chronic unpredictable stress (CUS) and in the inflammatory model of depression. However, the differences between SD and WH in these experimental models are not well studied. The aim of the present study was to compare alterations in the hedonic status, food consumption and body weight of male SD and WH rats obtained from Charles River Laboratories (Germany), in the CUS model (7 weeks) and in acute low-dose endotoxemia (single intraperitoneal injection of a low subseptic dose of LPS, 25 mu g/kg). Hedonic status was assessed using the sucrose preference test without prior food and water deprivation. Significant differences were found between SD and WH in the body weight gain, food consumption, locomotor and exploratory activity, and in the mass of the thymus. WH rats demonstrated a lower threshold of sucrose preference (0.3%) compared to SD rats (0.4%). The effects of both CUS and endotoxemia on body weight were more pronounced in SD rats. In endotoxemia, a decrease in hedonic status was more pronounced in WH rats. LPS-induced serum levels of TNF-alpha were higher in SD, and corticosterone was higher in WH (90 min after LPS). In the CUS model, changes in hedonic status and adrenal hypertrophy were detected only in SD rats, but thymic involution was detected only in WH. Significant differences in the physiological characteristics of Sprague Dawley and Wistar Han rats and the different sensitivity of their metabolic and hedonic status to stress and inflammation can have a significant impact on the results obtained in the models of the corresponding pathologies, as well as on their interpretation.

Parkinson's disease (PD) is a neurodegenerative pathology resulting from the degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Neurotrophic factors (NTFs) and their receptors are key regulators of the survival, differentiation, and development of neurons. However, the role of these factors in the pathogenesis of PD is still unclear. Here, we analyzed the expression of NTFs and their receptors in human induced pluripotent stem cells (iPSCs) derived from the fibroblasts of patients with PD and healthy donors (HDs). Four PD-derived iPSC lines with different mutations and three cell lines from HDs at different stages of neuronal differentiation were used for RT-qPCR analysis and ELISA. We found that the mRNA levels of most analyzed genes were altered in PD-derived cells compared with those in HD-derived cells at all stages. Importantly, irrespective of PD-associated mutations, the mRNA levels of the BDNF and GDNF genes were mostly increased or unchanged in predominantly DA terminally differentiated neurons (TDNs) compared with those in HD-derived cells. Strikingly, in contrast to BDNF and GDNF mRNA levels, BDNF and GDNF protein levels were lower in almost all PD-derived TDNs than in HD-derived cells, thus indicating the dysregulation of NTF expression at the post-transcriptional level. We suggest that this dysregulation is one of the important signs of PD development.

Exposure to stress during early postnatal development can cause neurological disorders in adulthood. The aim of this study was to evaluate changes in behavior, learning ability, and the content of the neurotrophic factor BDNF in rats that underwent neonatal stress. In addition, we studied the possibility of correction of the effects of neonatal stress by subsequent administration of an analog of the ACTH(4-10) fragment Semax. Neonatal isolation (NI) was used as a stress stimulus. Rat pups were separated from their mother and littermates for 5 h per day each day during the period from the 1st to the 14th day of life. The control animals were left in their nest in the first 2 weeks of life. From the 15th to 28th day of life, half of the rats subjected to NI were intranasally treated with Semax daily at a dose of 0.05 mg/kg. The remaining animals received intranasal injection of solvent at the same time. It has been shown that NI leads to an increase in the level of anxiety, a slight increase in depression, and impaired retention of the passive avoidance task in rats during the second month of life. At the age of 1 month, we observed an increase in the content of BDNF in the frontal cortex in the rats with NI; at the age of 2 months, a decrease occurred in the neurotrophin level in the hippocampus. Administration of Semax to rats subjected to NI decreased anxiety and depression, improved learning ability, and normalized the BDNF content in brain structures of animals. Therefore, chronic intranasal Semax administration after NI weakens the negative effects of neonatal stress.

Perinatal hypoxia-ischaemia is one of the leading factors that negatively influence the development of the central nervous system. Our aim was to investigate the effects of sex on the outcomes of acute neonatal hypoxia (ANH) in rat pups. Male and female Wistar rats were exposed to a hypoxic condition (8% oxygen for 120 min) at postnatal day 2 (P2). Immediately after ANH an increase in HIF1-alpha gene expression was observed in the rat brains, independently of sex. Brain-derived neurotrophic factor (BDNF) and glutathione peroxidase-4 gene expression was increased in female animals only. Hypoxic pups of both sexes showed a decreased reduced/oxidised glutathione (GSH/GSSG) ratio in the blood and only males had an increased GSH content in the whole brain immediately after hypoxia. Furthermore, an increased BDNF content in the brain was found in both male and female rat pups at 0 h and in serum 4 h after hypoxia, but at 4 h after hypoxia only males had an increased BDNF level in the brain. Only hypoxic males displayed retarded performance in the righting reflex, but in a negative geotaxis test hypoxic pups of both sexes had an increased turnaround time. Moreover, hypoxic female but not male pups demonstrated less weight gain than control littermates for the entire observation period (until P18). These results demonstrate that ANH at P2 leads to both molecular and physiological impairments in a sex-specific manner and the described model could be used to represent mild hypoxic brain damage in very preterm infants.

Adverse experience during the early postnatal period induces negative alterations in physiological and neurobiological functions, resulting in long-term disorder in animal behavior. The aim of the present work was to study the long-lasting effects of chronic neonatal stress in white rats and to estimate the possibility of their correction using Semax, an analogue of ACTH fragment (4-10). Early neonatal isolation was used as a model of early-life stress. Rat pups were separated from their mothers and littermates for 5 h daily during postnatal days 1-14. The pups of the control group were left undisturbed with the dams. Half of the rats subjected to neonatal isolation received an intranasal injection of Semax at a dose of 50 g/kg daily, from postnatal day 15 until day 28. The other animals received intranasal vehicle injections daily at the same time points. It was shown that neonatal isolation leads to a delay in physical development, metabolic disturbances, and a decrease in the corticosterone stress response in white rats. These changes were observed during the first two months of life. Semax administration weakened the influence of neonatal isolation on the animals, body weight , reduced metabolic dysfunction, and led to an increase in stress-induced corticosterone release to the control values. So the chronic intranasal administration of Semax after termination of the neonatal isolation procedure diminishes the negative effects of neonatal stress.

Alpha-melanocyte-stimulating hormone (α-MSH) is a regulator of many physiological processes that has neuroprotective characteristics. In this work, we showed the expression of the melanocortin receptor MC4R in cultured rat hippocampal astrocytes. We found a twofold increase in the expression of vascular endothelial growth factor in cultured rat hippocampal astrocytes in one hour after application of α-MSH at concentrations of 0.1 to 10 nM. The selective MC4R antagonist HS028 prevented stimulation of VEGF expression. These data suggest that the neuroprotective effects of α-MSH may be mediated by the stimulation of production of growth/neurotrophic factors in hippocampal astrocytes.

To examine the effects of the tat and nef regulatory genes of human immunodeficiency virus (HIV-1) on cell differentiation we used the mouse embryonic stem cells (ESC) as a model. Proliferation, embryoid bodies (EB) formation and subsequent differentiation into cardiomyocytes, glial and neuronal cells were investigated in ESC lines transfected with these genes. It has been shown that the transfection of ESC by the tat gene increased their proliferating activity, whereas the nef gene transfected ESC showed its decrease. The number of embryoid bodies formed was higher in the cultures of ESC transfected by the nef and lower in the cells transfected by the tat in comparison with controls. The percentage of embryoid bodies with contracting cardiomyocytes was higher against control in the nef transfected cells and lower in ESC transfected with the tat. There were no reliable differences in the appearance of glial cells between control and the nef and tat transfected cell lines. Spontaneous differentiation of ESC into neuronal cells was almost not observed in the nef transfected cells, in contrast to control and the tat transfected cells. However, addition of retinoic acid (RA) to the nef transfected cells caused even a slight increase in neuron formation as compared to control ESC treated with RA. Thus, for the first time we have shown that the tat and nef regulatory genes of HIV-1 had a visible effect on proliferation of ESC and some first steps of their differentiation. In general, the reverse correlation between the effects of these two viral genes on ESC proliferation and differentiation were observed.

Работа посвящена применению равномерно меченных тритием пептидов для изучения их биодеградации in vivo и in vitro. Реакцией высокотемпературного твердофазного каталитического изотопного обмена (ВТКИО) со спилловер-тритием получены равномерно меченные тритием биологически активные пептиды с молярной радиоактивностью 50-150 Ки/ммоль. Распределение изотопной метки по всем аминокислотам в этих пептидах позволяет определять практически все возможные продукты их ферментативного гидролиза одновременно. Разработанный метод анализа включает экстракцию органическими растворителями меченных тритием пептидов из тканей организма и хроматографиче-ское выделение индивидуальных меченых пептидов из смеси продуктов биодеградации. Концентрацию исследуемого пептида и продуктов его биодеградации рассчитывают с использованием жидкостного сцинтилляционного счета. С использованием описанного подхода исследованы пути биодеградации пептидов TKPRPGP (Селанк) и трипептида PGP в плазме крови. Исследована также фармакокинетика пептидного анксиолитика Селанка в тканях мозга при интраназальном введении in vivo. Определены концентрации меченых пептидов и показано, что основными продуктами биодеградации Селанка являются пентапептид TKPRP, трипептид ТКР, дипептиды RP и GP. Исследована биодеградация гептапептида MEHFPGP (Семакс) в присутствии нервных клеток и определено, что основными продуктами его биодеградации являются пентапептид HFPGP, трипептид PGP. Исследовано влияние на энкефалиназную активность плазмы крови с использованием равномерно меченного тритием [Lеu]энкефалина. Показано, что высокая ингибирующая способность Семакса на энкефалиназы плазмы крови связана с его действием на аминопептидазы. Предложенный метод, основанный на использовании равномерно меченных тритием пептидов, дает возможность как определять концентрацию пептидов в тканях in vitro и in vivo, так и оценивать активность ферментов, участвующих в их деградации.