Background: Recent epidemiological evidence indicates that the fetal environment can influence susceptibility to later disease during the lifespan. Prenatal stress exposure alters the programming of the metabolic and endocrine balance of various organs, including the auditory system. Objectives: The current study aimed at evaluating how prenatal stress influences Auditory Brainstem Responses. Methods: Eighteen pregnant Wistar RATs were stressed during a one-month gestation by chronic mild stress (CMS, a variable schedule of different stressors). After birth, the offspring’ s hearing thresholds and latencies were evaluated and compared with the control group. The hearing thresholds were assessed by recording auditory evoked brainstem responses to 4, 8, 12, and 16 kHz tone burst. Results: The results showed that although CMS caused a significant increase in corticosterone in pregnant mothers, the offspring with CMS experience had significantly lower body weight than control animals (P < 0. 00) yet there was no difference between hearing sensitivity of prenatally stressed offspring and the control group. However, ABRs showed a marked prolongation in wave II and IV latencies in prenatally stressed RATs (P < 0. 05). Conclusion: The current data confirmed that prenatal exposure to mild stress is not detrimental to hearing sensitivity. However, these data suggest that prenatal stress can affect the temporal processing of auditory stimuli in the brainstem.

The extensive application of silver nanoparticles (AgNPs) has been increased due to their antimicrobial properties, however numerous concerns has been arisen about their toxicity potential. Since nanoparticles can cross through the placenta and accumulate in the embryonic organs especially liver, in this study, developmental hepatotoxicity of AgNPs was investigated.Pregnant RATs were divided into two groups, vehicle control group and treated group. Treated group received AgNPs (25 mg/Kg) through intra-gastric gavage in a period of gestational days1-19. PUPS were sacrificed after the birth and their livers collected. Histopathology, ICP- mass spectrometry, Spectrophotometric assay, and ELISA were employed to evaluate AgNPs toxicity in the liver of PUPS.Glutathione peroxidase (GPX) activity and glutathione (GSH) level were significantly decreased and malondialdehyde (MDA) and caspase 9 levels were significantly increased, although there was no significant change in caspase 8 content in the liver of offspring. FattydegeneRATion and congested dilated sinusoids were also observed in histo-pathological examination.These results suggest that maternal oral exposure to AgNPs may induce oxidative stress and apoptosis in the liver of their offspring. Further investigations are required to clarify molecular events behind this happening.

Introduction: This study investigated the effect of the environmental enrichment during adolescence on morphine-induced Conditioned Place Preference (CPP) and locomotor sensitization in maternally sepaRATed male and female RAT PUPS.Methods: Male Wistar RATs were allowed to mate with female virgin Wistar RATs. PUPS were sepaRATed from them 3 hours per day during 2–14 days postnatal. All PUPS were weaned at 21 Postnatal Day (PND) and reared in standard environment or enriched environment from 21 to 50 PND with litter-mates of the same sex. The CPP and behavioral sensitization to morphine were assessed by an unbiased place conditioning paradigm and open filed method.Results: The results showed that the maternal sepaRATion enhanced morphine-induced CPP in both sexes, locomotor sensitization in male PUPS and tolerance to morphine-induced motor activity in female PUPS during adolescence. While, male and female PUPS reared in an EE exhibited a decrease in morphine-induced CPP, locomotor sensitization and tolerance induced by maternal sepaRATion compared to their control PUPS.Conclusion: Access to enriched environment during adolescence may have a protective effect against morphine-induced reward, locomotor sensitization and tolerance in adolescent male and female RATs following maternal sepaRATion.

The biological effects of omega-3 and omega-6 fatty acids are determined by their mutual interactions. This interaction extremely affects various functions. Lower consumption of omega-3 during gestation leads to various disorders, even in hearing. We aimed to assess the effect of low omega-3/omega-6 RATios on auditory nerve conduction. In this experimental study, the auditory brainstem response test was performed on a 24-day-old RAT (n=14). The RATs were divided into case (low omega-3/omega-6 RATio during gestation and lactation) and control groups. Variables such as P1, P3, and P4 absolute latency period, interpeak (P3-P4, P1-P3 and P1-P4), and P4/P1 amplitude RATio were measured. We found an increased P4 omega-3/omega-6 RATio in the group with a low omega-3/omega-6 RATio (P<0.01). No significant difference was observed in the P1 and P3 absolute latency period between the studied groups (P>0.05). Also, no significant difference was observed between the groups with respect to the P1-P3 interpeak latency (IPL) periods (P>0.05); while the P1-P4 and P3-P4 IPLs were significantly increased in the group with a low omega-3/omega-6 RATio (P<0.05). The P4/P1 amplitude RATio significantly decreased in the group with a low omega-3/omega-6 RATio (P<0.05). Results confirmed the negative effects of low omega-3/omega-6 RATio on the auditory system and hearing.