Alterations in the social-conditioned place preference and density of dopaminergic neurons in the ventral tegmental area in Clsnt2-KO mice.

The incidence of autistic spectrum disorders (ASD) constantly increases in the world. Studying the mechanisms underlying ASD as well as searching for new therapeutic targets are crucial tasks. Many researchers agree that autism is a neurodevelopmental disorder. Clstn2-KO mouse strain with a knockout of calsyntenin 2 gene (Clstn2) is model for investigating ASD. This study aims to evaluate the social-conditioned place preference as well as density of dopaminergic (DA) neurons in the ventral tegmental area (VTA), which belongs to the brain reward system, in the males of the Clstn2-KO strain using wild type C57BL/6J males as controls. Social-conditioned place preference test evaluates a reward-dependent component of social behavior. The results of this test revealed differences between the Clstn2-KO and the control males, as the former did not value socializing with the familiar partner, spending equal time in the isolation- and socializing-associated compartments. The Clstn2-KO group entered both compartments more frequently, but spent less time in the socializing-associated compartment compared to the controls. By contrast, the control males of the C57BL/6J strain spent more time in socializing-associated compartment and less time in the compartment that was associated with loneness. At the same time, an increased number of DA and possibly GABA neurons labeled with antibodies against the type 2 dopamine receptor as well as against tyrosine hydroxylase were detected in the VTA of the Clstn2-KO mice. Thus, a change in social-conditioned place preference in Clstn2-KO mice as well as a higher number of neurons expressing type 2 dopamine receptors and tyrosine hydroxylase in the VTA, the key structure of the mesolimbic dopaminergic pathway, were observed.

[Effects of a high-fat diet on the lipid profile of oocytes in mice]. / Влияние диеты с повышенным содержанием жира на липидный профиль ооцитов мышей.

There are evidences that obese women exhibit a detrimental oocyte quality. However, it remains unclear how this change is associated with obesity, indirectly - or directly through a change in the content and/or composition of lipids in oocytes. The aim of this work was to study effects of a high-fat diet applied to female donor mice on the amount and qualitative composition of lipids of immature and in vivo matured oocytes. A high-fat diet caused larger body weight in female mice compared with the control ( p < 0.001; 44.77 ± 1.46 and 35.22 ± 1.57, respectively), and increased the blood levels of cholesterol ( p < 0.05; 2.06 ± 0.10 and 1.78 ± 0.10, respectively) and triglycerides ( p < 0.05; 2.13 ± 0.23 and 1.49 ± 0.21, respectively). At the same time, this diet does not affect the level of unsaturation of lipids in immature (0.207 ± 0.004 in the experiment and 0.206 ± 0.002 in the control) and matured oocytes (0.212 ± 0.005 in the experiment and 0.211 ± 0.003 in the control). Total lipid content increased during in vivo maturation of mouse oocytes. The amount of lipids was greater in mature oocytes in the experimental group compared to the control ( p < 0.01; 8.15 ± 0.37 and 5.83 ± 0.14, respectively). An increase in intracellular lipid amount during oocyte maturation was revealed both after a standard diet ( p < 0.05; 4.72 ± 0.48 and 5.83 ± 0.14, respectively) and after a fat-rich diet ( p < 0.001; 3.45 ± 0.62 and 8.15 ± 0.37, respectively). Thus, during in vivo oocyte maturation in mice the content of intracellular lipids enhanced, the high-fat diet aggravated this dynamics of lipid increase during in vivo maturation of oocytes.

Cryopreservation and In Vitro culture of Preimplantation Embryos in Djungarian Hamster (Phodopus sungorus).

Although embryo cryobanking was applied to Syrian golden and to Campbell's hamsters, no attempt has been made at freezing embryos in Djungarian hamsters. Four-cell stage embryos were flushed from the reproductive ducts of pregnant females before noon of the third-day post coitum and frozen in 0.25-ml straws according to standard procedures of slow cooling. A mixture of permeating (ethylene glycol) and non-permeating (sucrose) cryoprotectants was used. The thawing was performed by incubating at RT for 40 s followed by 40 s in a water bath at 30.0°C. Most (66.7%) of the non-frozen four-cell embryos developed up to the morula stage in rat one-cell embryo culture medium (R1ECM). The use of hamster embryo culture medium (HECM) yielded fewer morulas (18.2%) during the same 24-h period of culture. The rate of embryo's surviving the freezing-thawing procedures, as estimated by light microscopy, was 60.7-68.8%. After 24-h culturing in R1ECM, 64.7% of frozen-thawed four-cell embryos developed and all of them reached the morula stage. Supplementation of R1ECM with GM-CSF (2 ng/ml) improved the rate of Djungarian hamster frozen-thawed embryo development: 100% of the four-cell stage embryos developed, 50% of them achieved the morula stage, and 50% developed even further and reached the blastocyst stage within 24 h of culturing. This study reports the world's first successful transfer of frozen-thawed Djungarian hamster embryos yielding term pups. Taken together, the results of this study demonstrate the possibility of applying some key reproductive technologies, that is, embryo freezing/cryopreservation and in vitro culture, to Djungarian hamsters.