A study of the 4-day rhythm of the proliferative activity of the embryonic fibroblast-like cells in the logarithmic growth phase was carried out. It was shown that in cell cultures obtained on ...different days from embryos of different ages, the phase of the 4-day rhythm coincides. In vitro the maxima of the proliferative activity were consistent with the minima of the motor activity of mice. Freezing the culture for 2 or 6 days does not cause a shift in the phase of the 4-day rhythm of cell proliferative activity compare with the unfreezing culture. That indicates the existence of an external synchronizer, which determines the 4-day infradian rhythm of the proliferative activity of embryonic cells. Then we daily thawed samples of single L929 culture of mice fibroblast-like cells for 22 and 17 days and researched the dynamics of its proliferative activity. We also showed 4-day rhythm of the simultaneous increase in the number of cells for all thawed samples. Taking into account that deep freezing of a culture leads to the cessation of all life processes, the fact we obtained indicates an exogenous mechanism of the formation of about a 4-day rhythm of the proliferative activity of cell culture. Variations of the Earth's magnetic field could be one of the external synchronizers of the infradian rhythm. We studied the increase in number of L929 cell in conditions of a magnetic permalloy screen and showed that the magnetic shielding no affect the parameters of the infradian rhythm of L929 cell proliferative activity. So further searches of the external synchronizers are need.
It is a common fact, that the content of sex hormones in humans and animals varies in different age periods. The functional state of the immune system also changes with age. However, sex differences ...studies of inflammatory and immune responses during puberty prevail in literature. Investigation of immune responses to LPS peculiarities in prepubertal females and males may contribute to the development of more effective immunotherapy and minimize side effects of children vaccination. Therefore, the aim of this work was to investigate the LPS-induced SIRS sex differences in prepubertal Wistar rats. Despite the absence of sex differences in estradiol and testosterone levels, LPS-induced inflammatory changes in liver and lungs are more pronounced among males. Males demonstrate the increasing neopterin, corticosterone levels and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity. Not less important is that in females, demonstrating less morphological changes in liver and lungs, endotoxin level is tenfold higher, and corticosterone level decreases. Thus, endotoxin cannot be used as a marker of the severity of multiple organ failure in prepubertal period. The LPS-induced immune reactions in females and males are similar and are characterized by immunosuppression. Both females and males have decreased production of cytokines (IL-2, IL-4, TNF-α, TGF-β) and the absolute number of CD3 + and CD3 + CD8 + lymphocytes in blood. The acute atrophy of thymus and apoptosis of thymic cells are revealed in animals of both sexes. However, the number of CD3 + CD4 + T-helpers and CD4 + CD25 + Foxp3 + T-cells decreases only in females with SIRS, and in males there was a decrease of CD45R + B-cells. The least expressed sex differences in immune responses in the prepubertal period can be determined by the low levels of sex steroids and the absence of their immunomodulatory effect. Further studies require the identification of mechanisms, determining the sex differences in the inflammatory and immune responses in prepubertal animals.
Dermal fibroblast cell culture is a convenient model for studying various effects on cells, including hypoxia. Fibroblasts, in addition to collagen production, are able to synthesize biogenic amines, ...hormones, neuropeptides, and neurotransmitters identical to those in the central nervous and endocrine systems, which allows them to be used to study cellular disorders in various diseases. The purpose of the study was to evaluate the functional changes in the culture of dermal fibroblasts under hypoxic conditions using biochemical and molecular biological methods. In cells of fibroblast culture under normoxia (air and 5% CO
2
in an incubator) and hypoxic exposure (a mixture of gases - 95% N
2
and 5% CO
2
) at 1 and 3 hours, biochemical methods were used to determine the activity of aspartate aminotransferase (AsAT), alanine aminotransferase (AlAT), gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), glucose levels, concentrations of ATP, ADP, AMP, as well as the level of mRNA expression of the hypoxia-induced factor Hif-1a and the nuclear factor Nf-κb by polymerase chain reaction. It was shown that under hypoxic exposure at 1 hour in fibroblast culture, cell viability, glucose levels and activity of LDH, AlAT, AsAT decrease, the amount of ATP decreases, after 3 hours there is a tendency to normalize all indicators. Adaptive mechanisms make it possible to normalize the functioning of cells under hypoxic conditions from 1 to 3 hours. The results obtained in the evaluation of metabolic changes at different times of hypoxic exposure (1 and 3 hours) in the culture of rat fibroblasts indicate a high adaptive capacity of connective tissue cells - fibroblasts at a lack of oxygen. The study of intracellular parameters during hypoxia, the determination of critical points depending on the time of exposure will determine the directions for further study of the mechanisms of cell adaptation, which, perhaps, will complement the tactics of compensatory effects in ischemia of tissues of various genesis. The revealed changes reflect the adaptive response of the fibroblast culture in response to hypoxic exposure.
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