Sex-dependent differences in stress-induced depression in Wistar rats are accompanied predominantly by changes in phosphatidylcholines and sphingomyelins.

With a high annual and lifetime prevalence, depression is becoming the leading contributor to the global disease burden. During the COVID-19 crisis, the depression and mood disorders accelerated significantly. Despite the growing evidence, the precise underlying mechanisms of depression disorders (DD) remain unknown. When studying DD in humans, there are many uncontrollable factors such as medication history, age of the patient or living conditions. In this regard, animal models provide an essential step for examining neural circuitry or molecular and cellular pathways in a controlled environment. As far as we know, women have a consistently higher prevalence of DD than men. Thus, the aim of our study was to evaluate sex-related changes in blood metabolites in a model of stress-induced depression in Wistar rats. Pregnant females were stressed using restriction of mobility in the final week of the pregnancy three times a day for 45 minutes each, three following days. After the birth, the progeny aged 60 days was stressed repeatedly. The perturbation in overall energy metabolism as well as in lipid metabolism was found. While in males, phosphatidylcholines (the most phosphatidylcholine with acyl-alkyl residue sum C40:4 - PC ae C40:4), sphingomyelins, and acylcarnitines were changed, in females, lipid metabolism perturbation was seen with the most critical alteration in hydroxysphingomyelin with acyl residue sum C16:1 (SM OH C16:1). Our results confirm that the animal model may be used further in the research of depression. Our results may provide an essential insight into the sex-dependent pathogenesis of depression and contribute to the search for effective treatment and prevention of depression with respect to sex.

"Neural stem cells puzzle" missing piece: telomerase reverse transcriptase expression patterns during nervous system ontogenesis in rats.

For almost three decades, neural stem cells remain still up-to-date and enigmatic topic. The main problem for their studying is the non-existence of an exclusive neural stem cell marker and the heterogeneity of them across the nervous system. As one of the novel markers of neural stem/progenitor cells may serve telomerase reverse transcriptase (TERT), a catalytic subunit of the telomerase enzyme, responsible for retaining the cell immortality. Thus, the aim of our study was to reveal if TERT, as an enzyme for ensuring the immortality of proliferating cells, could be used as a potential marker of neural stem/progenitor cells during the ontogenesis of the rat central nervous system. In this study, we used various markers related to neural stem or progenitor cells character and examined their co-localization with TERT expression. Our experiments were performed on the tissue of the brain and spinal cord during several stages of postnatal development and the neural tube during the 14th embryonal day. Cytoplasmatic TERT expression was found in alar plate progenitors and ventral horn neuroblasts of E14 rats. In the postnatal stages of spinal cord ontogenesis, a cytoplasmatic expression in neurons and nuclear expression in astrocytes was defined. In the brain, nuclear TERT expression was found in neural progenitor cells of neurogenic areas. This study provides the first comparative study of TERT expression across the central nervous system ontogenesis. The nuclear presence of TERT may be used as a potential marker of neural stem/progenitor cells, however, further studies are required to confirm these assumptions.