Prenatal stress leads to changes in IGF-1 binding proteins network in the hippocampus and frontal cortex of adult male rat

Depression is a mental disorder of still unknown origin. Currently, much attention is paid to the potential influence of disturbances in the functioning of neurotrophic factors on the onset of this disease. Insulin-like growth factor 1 (IGF-1) is one of the most important growth agents affecting processes that are crucial for brain development. To date, there are no data showing the impact of prenatal stress on the family of six IGF binding proteins (IGFBP 1-6) that regulate IGF-1 bioactivity. The goal of this study was to investigate whether the decreased expression of IGF-1 in the frontal cortex (FCx) and hippocampus (Hp) of adult male rats following a prenatal stress procedure is related to changes in the IGFBP family. Our results show that rats exposed prenatally to stressful stimuli displayed depression-like behavior based on sucrose preference and elevated plus maze tests. In both cases, in the adult rat brain structures that were examined after the prenatal stress procedure, the IGF-1 protein level was reduced. Moreover, we observed changes of varying degrees in the levels of IGFBPs in stressed animals. A decrease in IGFBP-2 and IGFBP-3 accompanied by an increase in the IGFBP-4 concentration in the Hp and the FCx was detected. There were no differences in IGFBP-1 and IGFBP-6 brain levels between the stressed and control animals, whereas IGFBP-5 concentration was decreased in the Hp of prenatally stressed animals. This study demonstrated that stress during pregnancy may lead not only to behavioral disturbances but also to a decrease in IGF-1 level and the dysregulation of the IGF-1 binding protein network in adult rat offspring.

Postimplantation development of mouse blastocysts with two separate inner cell masses

Blastocysts with double inner cell masses (ICMs) were produced by electrofusion of two blastocysts and transplanted to pseudopregnant recipients. The implanted embryos were either examined histologically (8th day of pregnancy) or dissected and inspected in toto (11th or 12th day). In most cases both ICMs of experimental blastocysts developed into separate egg cylinders. Both cylinders were located in the common yolk sac cavity. Some cylinders were quite normal, but most of them were small and deprived of embryonic membranes. Ectoplacental cones of these cylinders were often oriented laterally or even antimesometrially. The development of cylinders seems to depend upon the position of their ectoplacental cones--cylinders with cones situated antimesometrially were handicapped in development. Among four sets of twin embryos examined on the 11th or 12th day, in one set each of the twins were equally developed, and in the three others one of the twins was more advanced.