Drawbacks and Unexpected Advantages of the Response to Modeling Posttraumatic Stress Disorder in Old Wistar Rats.

In modeling post-traumatic stress disorder (PTSD), old Wistar rats exhibit the same general signs of a PTSD-like condition as young rats do. The ratio of testosterone to corticosterone levels was assessed as a new index and proved to provide a guideline for dividing the rat population into low- and high-anxiety groups when modeling PTSD. Several features were observed in behavior, psycho-emotional manifestations, hormone levels, and myocardial state in old rats. A sharp rise in circulating testosterone was for the first time shown to occur in old, but not young, rats in stress, contributing to a more rapid decision as to where to move in the labyrinth space. Priority data were obtained on dysfunctional accumulation of mitochondria in the myocardium in intact and stressed old rats. The information obtained may be useful in developing drugs against harmful consequences of PTSD and senile changes in the myocardium.

The Search for Diagnostic Criteria to Divide the Wistar Rat Population into Phenotypes during Modeling of Post-Traumatic Stress Disorder.

The levels of circulating hormones (corticosterone, testosterone, and leptin) and interleukins were studied in sexually mature male Wistar rats against the background of post-traumatic stress disorder (predator threat stress). It was found that in addition to the previously used anxiety index determined by animal behavior, the population of stressed individuals can be divided into stress-resistant and stress-sensitive phenotypes by the level of leptin and the index of anabolism (testosterone/corticosterone ratio). For the first time, it was determined that in stress-resistant rats, the levels of leptin and the testosterone/corticosterone index exceeds the control values, while in stress-sensitive individuals, these indicators are much lower.

Changes in the Expression of Pluripotency Factor Oct-4 and Intensity of Apoptosis in the Uterus during Spontaneous and Immune-Dependent Abortions in Mice.

We studied the expression of pluripotency factor Oct-4 and the intensity of apoptosis in the uterus during spontaneous and immune abortions in mice. Increased expression of factor Bax and reduced protein Bcl-2 synthesis in cells of the decidual membrane and decreased Oct-4 expression in the myometrium and perimetrium were detected. Thus, both spontaneous and immune-dependent abortions impair the apoptosis processes in the decidua and the formation of a pool of Oct-4+ cells in the uterus. In immune-dependent abortions, the intensity of apoptosis of decidual cells was lower than in spontaneous abortion. Low expression of the transcription factor Oct-4 in the myometrium and perimetrium characterizes pregnancy failure irrespective of its mechanisms.

Analysis of Healing of Rat Uterine Wall After Full-Thickness Surgical Incision.

We studied the dynamics of morphological changes in the operated segment of the uterine horn of Sprague-Dawley rats during the first 2 weeks of the wound-healing process after a full-thickness surgical incision with regard to the estrous cycle phase. Morphometric parameters of injured uterine right horn were compared with those in the intact left horn of the same animal as a control of changes determined by the hormonal background. It was found that the uterine epithelium in the focus of injury was restored as soon as on day 2 after surgery under the influence of estrous cycle hormones. By day 4, the wound space was completely filled with the endometrial tissue on the side of the uterine lumen and coved by the attached adipose tissue of the mesentery on the side of the abdominal cavity. The thickness of the uterine wall and the uterine lumen differed most strongly between the operated and intact uterine horns during the first 3 days and on day 6 after surgery. The size of the healing area increased during the first three days and reached the peak value by day 3, but then decreased to minimum by day 6.

Comparison of the Adaptive Capacity in Old and Young Wistar Rats to Stress Exposure and Acute Hypoxic Hypoxia.

We compared behavioral and psychoemotional manifestations of young and old male Wistar rats in elevated plus-maze, the levels of corticosterone and testosterone, as well as the resistance to acute hypoxic hypoxia before and after stress exposure (10-min swimming sessions over 10 days). The behavioral characteristics, responses of the main stress hormone corticosterone, and resistance to acute hypoxic hypoxia were identical in both age groups before and after stress. A distinguishing feature was pronounced flattening of the psychoemotional manifestations in old animals. The main adaptive differences between young and old rats were revealed in the response of circulating testosterone to stress.

Proliferative Activity of Mouse Splenocytes in Physiological Pregnancy and in Models of Spontaneous and Muramylpeptide-Dependent Abortions.

Spontaneous proliferative activity of splenocytes in female CBA mice and the response of these cells to antigens of allogeneic male BALB/c and DBA/2 mice in a mixed splenocyte culture were evaluated by 3H-thymidine incorporation in different pregnancy models. ♀CBA×♂BALB/c mating was used for modeling physiological pregnancy. Spontaneous abortions were reproduced by abortion-prone ♀CBA×♂DBA/2 mating. In order to simulate immunostimulant-induced and immunostimulant-potentiated abortions, 0.83 mg/kg muramyl dipeptide ß-heptylglycoside was intraperitoneally injected to CBA females mated with BALB/c or DBA/2 males, respectively, on gestation days 5 and 7. The increase in the rate of embryo resorption in the models of spontaneous, induced, and potentiated abortions occurred against the background of an increase in the level of spontaneous proliferation of splenocytes and a decrease in their reactivity to paternal antigens on gestation day 9.

Intraperitoneal Administration of Muramyl Dipeptide ß-Heptylglycoside to Pregnant and Non-Pregnant Female Mice Modulates Production of Th1/Th2/Th17/Tr1 Cytokines by Splenocytes Ex Vivo.

Muramyl dipeptide ß-heptylglycoside (C7MDP) was administered to non-pregnant CBA female mice and pregnant mice after non-abortion-prone mating (CBA×BALB/c) and mating associated with a high rate of spontaneous abortion (CBA×DBA/2). In non-pregnant females, C7MDP increased the production of IL-2, IL-4, IL-5, IL-6, IL-17, IFNγ, TNFα, and GM-CSF at constant production of IL-1α and IL-10. C7MDP increased the production of IL-10 and IL-17 and suppressed the production of IFNγ on day 8 of gestation in non-abortion-prone mouse couples and stimulated the synthesis of IL-4 and IFNγ, reduced IL-5 production, and slightly increased IL-1α secretion after abortion-prone mating. On day 14 of gestation, C7MDP elevated the yield of IL-2, IL-4, IFNγ, TNFα, and GM-CSF in CBA×BALB/c and CBA×DBA/2 couples and IL-17 in the fi rst variant of mating.

Structural changes in the thymus in allogenic pregnancy in mice with high incidence of spontaneous and muramylpeptide-induced abortions.

Structural changes in the thymus over the course of allogenic pregnancy were studied in mice from highly fertile couples (CBA females and BALB/c males), animals with high spontaneous abortions (CBA females and DBA/2 males), and in experimental immunity-dependent pregnancy loss induced by muramyldipeptide ß-heptylglycoside. Accidental involution of the thymus on days 8 and 14 of pregnancy was more pronounced in mice with high level of spontaneous embryo resorption than in females from highly fertile couples. Muramyldipeptide glycoside stimulated manifestations of thymus involution in fertile and "abortogenic" cross-breeding.