Studies show that gender plays an important role in stress-related disorders, and women are more vulnerable to its effect. The present study was undertaken to investigate differences in the change in expression of brain-derived neurotrophic factor (BDNF), and its tyrosine intracellular kinase-activating receptor (TrkB) genes in the male and female rats' hippocampus (HPC) under chronic mild repeated stress (CMRS) conditions. In this experiment, male and female Wistar rats were randomly divided into two groups: the CMRS and the control group. To induce stress, a repeated forced swimming paradigm was employed daily for adult male and female rats for 21 days. At the end of the stress phase, elevated plus maze (EPM) was used for measuring the stress behavioral effects. Serum corticosterone level was measured by ELISA. BDNF and TrkB gene methylation and protein expression in the HPC were detected using real-time PCR and Western blotting. Chronic stress in the adolescence had more effects on anxiety-like behavior and serum corticosterone concentration in female rats than males. Furthermore, stressed female rats had higher methylation levels and following reduced protein expression of BDNF but not TrkB compared to stressed male rats. These findings suggest that in exposure to a stressor, sex differences in BDNF methylation may be root cause of decreased BDNF levels in females and may underlie susceptibility to pathology development.
Hepatitis D (delta) virus (HDV) is a subviral pathogen agent and a satellite of Hepatitis B virus. Three distinct genotypes are described for HDV; genotype I is distributed worldwide but other genotypes appear to be more restricted geographically. In the present study, the entire nucleotide sequence of an HDV isolate from an Iranian patient (IR-1) was obtained using twelve pairs of primers to amplify six overlapping fragments covering the whole HDV genome by RT-nested PCR. Phylogenetic and pairwise alignments were done on this new isolate to determine IR-1 position among other isolates. Our results indicate that IR-1 contains 1676 nucleotides encoding 214 a.a. of the hepatitis delta antigen (HDAg). This new isolate belongs to genotype I with most sequence similarity to an Italian HDV isolate (92.6%). At amino acid level, predicted HDAg sequence of IR-1 revealed the most homology with those of Italian and Lebanese isolates. Data analysis confirmed genetic variability and heterogeneity of the HDV species isolated from different geographical areas.
Environmental factors, especially stress, can remain pervasive effects across the lifespan. Traumatic experiences are risk factors for the behavioral and emotional disorders. Since brain-derived neurotrophic factor (BDNF) is the important regulator of neural survival, development, and its genetic and epigenetic alterations which have been linked with several neuropsychiatric disorders, the present study investigated the effect of maternal adulthood stress on molecular changes of BDNF and tyrosine kinase-coupled receptor (TrkB) in the hippocampus of 30-day-old offspring. To induce stress, we employed a repeated forced swimming model for female rats across 21 days. Then, they were divided into two parental breeding groups: stressed mother (SM) and non-stressed mother (NSM) or control group. Anxiety-like behavior was tested in adult female rats and 30-day-old pups by using the elevated plus maze (EPM). The level of serum corticosterone was also measured by ELISA. BDNF and TrkB gene methylation and protein expression in the hippocampus were detected using real-time PCR and Western blotting in all groups. Thirty-day-old male and female pups from SM groups had a significantly more serum corticosterone concentration, DNA methylation levels of BDNF and TrKB, and lower expression of these genes compared to pups from the control groups. Also, male pups from stressed mother exhibited significant anxiety-like behavior compared to male pups from the control mothers. These findings suggest that molecular changes formed by maternal stress experience even before conception persist to the next generation and will negatively influence on phenotypes of offspring.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.