Safety evaluation of ondansetron after gestational exposure on male reproductive parameters in rats.

Ondansetron is a 5HT3 receptor antagonist widely used to treat hyperemesis gravidarum, although its safety is still questionable. Since 5HT3 receptors, which are the target of this drug, can interfere with brain development through changes in neurotransmitter levels, this study evaluated whether the prenatal exposure to this drug could compromise reproductive and behavioral parameters in male offspring. Pregnant rats were treated with ondansetron (1.7 and 2.5 mg/kg/body weight; gavage), from gestational day 1-21. No exposure-related changes in clinical signs, body weight, food consumption, pregnancy length, and necropsy findings were observed in dams. Ondansetron exposure did not alter the anogenital distance or age of preputial separation in male offspring. Similarly, males exposed to therapeutic doses of ondansetron did not exhibit changes in play behavior. In adulthood, there were no changes in sperm parameters, as well as in testosterone level, sexual behavior and fertility. Furthermore, ondansetron did not interfere with testicular and epididymal histology, and with androgen receptor expression in hypothalamus. In conclusion, prenatal exposure to ondansetron did not cause maternal toxicity, as well as did not interfere with reproductive parameters of male offspring, indicating its safety after gestational exposure in rats.

Reproductive Development of Male Rats Exposed In Utero to Stress and/or Sertraline.

Despite increased prescription of sertraline during pregnancy, little is known about its action on reproductive development. Therefore, this study aimed to investigate the impact that stress, associated or not with sertraline, causes on the reproductive development of male rats. Pregnant Wistar rats were divided into 4 groups (n = 16/group): CO-received filtered water; SE-received 20 mg/kg sertraline; ST-submitted to restraint stress and received filtered water; SS-submitted to restraint stress and received sertraline. The treatment was carried out from gestational days (GDs) 13-20. The animals were euthanized on GD 20 (n = 8/group), postnatal day (PND) 45 (n = 8/group), and PND 110 (n = 8/group). The testes and epididymis were analyzed histologically, and immunohistochemistry was performed on the testes by proliferating cell nuclear antigen (PCNA) and the Wilms tumor protein (Wt1). Sperm quality was also analyzed on PND 110. The evolution of body weight, anogenital distance (AGD), and puberty installation day were also verified. Statistical analysis: 2-way ANOVA or Kruskal-Wallis test (p ≤ .05). Fetal testes presented a large number of acidophilic cells in the sertraline-exposed groups. The SS group also showed a decrease in the nuclear volume of Leydig cells. This same group showed low expression of PCNA and Wt1, decreased weight of the testes and epididymis, lower AGD, and delayed puberty installation. The adulthood groups exposed to sertraline presented alterations in sperm morphology and motility. The results demonstrated that prenatal exposure to sertraline compromises the development of the rat reproductive system.

Short Juvenile Stress Has No Long-Lasting Effects on Anxiety-Like Behavior, Object Recognition Memory, or Gross Brain Morphology but Affects Dendritic Spines in the Hippocampus in Male Rats.

PURPOSE: During the juvenile stage, such areas as the hippocampus and corpus callosum (CC) are still immature and sensitive to stress exposure. The present study investigated whether two different types of stressors in the juvenile stage of life have a long-lasting impact on behavior and biological outcomes in adult rats. METHODS: Male juvenile rats were exposed to restraint or predator stress on postnatal day 25 (P25) for 3 days. Thirty-two days later (P60-74), behavioral and biological analyses were conducted. The behavioral analysis included measures of anxiety-like behavior and recognition memory. The biological analysis investigated gross cerebral morphology, based on volume analysis of the CC and hippocampus, perirhinal cortex thickness, and dendritic spine density. RESULTS: Neither restraint stress nor predator stress affected anxiety-like behavior or object recognition memory in adulthood. Body weight and adrenal gland weight were unaffected by both types of stress. Overall, volumetric measures of the CC and hippocampus were not significant, with no changes in perirhinal cortex thickness. Spine density in the medial prefrontal cortex also was unaffected, but a decrease in dendritic spine density was found in the hippocampus in response to restraint stress and an increase to predator stress. CONCLUSION: Short-term and daily restraint and predator stress during the juvenile stage had no long-lasting effects on anxiety-like behavior, object memory, volume of the CC or hippocampus, or perirhinal cortex thickness, but a decrease in dendritic spine density was found in the hippocampus. These findings suggest that different types of stressors have different impacts on microstructures in the brain without affecting behavior or the gross morphology of stress-sensitive brain areas.

Cognitive training increases dendritic arborization in the dorsal hippocampal CA1 and CA3 neurons of female and male Long-Evans rats.

Experiences influence the development of the central nervous system. Cognitive training promotes changes in the structure of the brain, such as in its weight and number of cells, as well as ability to perform dendritic remodeling. The present study was designed to detect possible differences in the neuronal morphology of the dorsal hippocampus between female and male Long-Evans rats after cognitive training (CT). CT was promoted through three learning and memory tests: the Morris water maze, the Barnes circular maze, and Novel object recognition tests. Our data revealed no differences in learning or memory capacities between female and male rats; rats of the two sexes solved the behavioral test with equal efficiency. CT caused an increase in the basilar and apical dendritic arborization of CA1 neurons in male rats, whereas female rats that underwent CT presented only remodeling in the apical arbors of CA1 neurons. The basilar arbors of CA3 neurons of female rats showed an increase in arborization, but their apical arbors were not modified; the arbors of CA3 neurons of male rats submitted to CT were not modified. Total dendritic length was modified by CT in the apical arbors of CA1 neurons of female and male rats and in the basilar CA1 arbors of male rats. There was a significant increase in dendritic spine density in all arbors of CA1 and CA3 neurons of females and males subjected to CT. These results suggest that dendritic remodeling after CT is similar between female and male rats.

Postnatal exposure to a glyphosate-based herbicide modifies mammary gland growth and development in Wistar male rats.

Our aim was to evaluate whether postnatal exposure to a glyphosate-based herbicide (GBH) modifies mammary gland development in pre- and post-pubertal male rats. From postnatal day 1 (PND1) to PND7, male rats were injected subcutaneously every 48 h with either saline solution (vehicle) or 2 mg GBH/kg·bw. On PND21 and PND60, mammary gland and blood samples were collected. Estradiol (E2) and testosterone (T) serum levels, mammary gland histology, collagen fiber organization, mast cell infiltration, proliferation index, and estrogen (ESR1) and androgen receptor (AR) expression levels were evaluated. At PND21, GBH-exposed male rats exhibited greater development of the mammary gland with increased stromal collagen organization and terminal end buds (TEBs) compared to control rats. At PND60, the number of TEBs remained high and was accompanied by an increase in mast cell infiltration, proliferation and ESR1 expression in GBH-exposed male rats. In contrast, no effects were observed in E2 and T serum levels and AR expression in both days studied. Our results showed that a postnatal subacute treatment with GBH induces endocrine-disrupting effects in the male mammary gland in vivo, altering its normal development.

Acrocomia aculeata oil: Beneficial effects on cyclophosphamide-induced reproductive toxicity in male rats.

This study aimed to evaluate the effects of the extracted oil of Acrocomia aculeata pulp in preventing or mitigating the reproductive toxicity induced by cyclophosphamide (CP) in male rats. Adult male rats were segregated into seven groups that received vehicle, 100 mg/kg/day of CP, or 10 mg/kg/day of ß-carotene or 3 or 30 mg/kg/day of A. aculeata oil co-administered with CP. A. aculeata oil exhibited a high content of ß-carotene. CP treatment induced reproductive toxicity in the animals, as it changed the reproductive organs weight, hormone levels, sperm counts and testicular histology. In contrast, co-administration of A. aculeata improved CP-induced alterations in these parameters. A. aculeata oil also increased the gene Ckit expression and normalised the antioxidant enzymes levels which were changed by CP. The A. aculeata oil is capable of protecting the male reproductive system from the adverse effects of CP, possibly by acting as an antioxidant and increasing the Ckit gene expression.

Changes in hormonal levels associated with enforced interval copulation and anxiety in sexually inexperienced and experienced male rats.

This study evaluated the effect of sexual experience on anxiety and hormonal levels associated with the performance of sexual behavior. Two groups of male rats, one with, the second without, sexual experience, were exposed to four different copulatory conditions: ad libitum copulation until ejaculation (ADC-E); enforced interval copulation until ejaculation (EIC-E); ad libitum copulation up to 3 intromissions (ADC-3I); and enforced interval copulation up to 3 intromissions (EIC-E3I). At the end of each condition the animals were subjected to an open-field test to measure anxiety, before being sacrificed to measure corticosterone (CORT) and testosterone (T) levels. The sexually-inexperienced males showed less hyperactivity, lower sexual motivation, and higher anxiety levels. Only in the ADC-E and EIC-E conditions did both the inexperienced and experienced rats have a higher number of entries to the central squares of the open-field test. Both the sexually-inexperienced and experienced male rats showed an increase in CORT levels, but only the latter had increased T levels under all copulatory conditions. These findings reveal that the anxiolytic effect of mating is dependent on previous sexual experience and the degree of control that the male rats had during sexual interaction. The changes in the levels of both hormones could be part of the physiological process necessary to satisfy the demands involved in sexual performance and open filed. These data provide further insight into the role of sexual experience in mediating the release of CORT and T, as well as the anxiolytic effects of ejaculation.

Neurovascular unit alteration in somatosensory cortex and enhancement of thermal nociception induced by amphetamine involves central AT1 receptor activation.

The use of psychostimulants, such as amphetamine (Amph), is associated with inflammatory processes, involving glia and vasculature alterations. Brain Angiotensin II (Ang II), through AT1 -receptors (AT1 -R), modulates neurotransmission and plays a crucial role in inflammatory responses in brain vasculature and glia. Our aim for the present work was to evaluate the role of AT1 -R in long-term alterations induced by repeated exposure to Amph. Astrocyte reactivity, neuronal survival and brain microvascular network were analysed at the somatosensory cortex. Thermal nociception was evaluated as a physiological outcome of this brain area. Male Wistar rats (250-320 g) were administered with AT1 -R antagonist Candesartan/vehicle (3 mg/kg p.o., days 1-5) and Amph/saline (2.5 mg/kg i.p., days 6-10). The four experimental groups were: Veh-Sal, CV-Sal, Veh-Amph, CV-Amph. On day 17, the animals were sacrificed and their brains were processed for Nissl staining and immunohistochemistry against glial fibrillary acidic protein (GFAP) and von Willebrand factor. In another group of animals, thermal nociception was evaluated using hot plate test, in the four experimental groups, on day 17. Data were analysed with two-way anova followed by Bonferroni test. Our results indicate that Amph exposure induces an increase in: neuronal apoptosis, astrocyte reactivity and microvascular network, evaluated as an augmented occupied area by vessels, branching points and their tortuosity. Moreover, Amph exposure decreased the thermal nociception threshold. Pretreatment with the AT1 -R blocker prevented the described alterations induced by this psychostimulant. The decreased thermal nociception and the structural changes in somatosensory cortex could be considered as extended neuroadaptative responses to Amph, involving AT1 -R activation.

Sexual Stimulation Increases the Survival of New Cells in the Accessory Olfactory Bulb of the Male Rat.

Sexual behavior in rodents is modulated by the olfactory system. The olfactory bulb (OB) is a structure that undergoes continues neurogenesis in adulthood. We have previously shown that 15 days after males rats pace the sexual interaction and ejaculate 1 or 3 times, there is an increase in the density of new cells that reach the accessory olfactory bulb (AOB). The aim of the present study was to evaluate if sexual behavior in male rats increases the density of new neurons that survive 45 days after sexual behavior in the AOB and in the main OB (MOB). Male rats were randomly divided in four groups: (1) Control (Ctr), males without sexual interaction; (2) Exposed (Exp), males only exposed to a sexually receptive female; (3) No pacing (NP), males that mated in conditions in which the female paced the sexual interaction; (4) One ejaculation (1E), males that paced the sexual interaction with a receptive female and ejaculated once; and (5) Three ejaculations (3E), males that paced the sexual interaction and were allowed to ejaculate three times. All males were injected with the DNA synthesis marker 5-bromo-2-deoxyuridine (BrdU), and were tested in one of the above conditions. 45 days later they were sacrificed, and the OBs were processed to identify new cells and evaluate if they had differentiated into neurons. Our data indicate that males that ejaculated three times showed an increase in the density of new cells that survive in the posterior part of the granular cell layer of the AOB and have more new neurons that the control group. However, no significant differences were found in the percentage of new cells that differentiate into neurons. No significant increase in the density of new cells was observed in the MOB. Our data show that pacing the sexual interaction until three ejaculations increases the density of new cells and neurons in the granular layer of the AOB, confirming that sexual behavior induces long-lasting plastic changes in the OB.

The effects of chronic restraint on the morphology of ventral CA1 neurons in female Long Evans rats.

Women are more likely than men to develop psychopathology as a result of stress, but there is little research regarding the effects of a stressful condition and its treatment in female non-human animals, perhaps because of inherent hormonal activity. Recent studies have demonstrated that there are structural and functional differences between the dorsal and ventral hippocampus, but the effects of stress on the morphology of CA1 and CA3 neurons have been studied primarily in the dorsal hippocampus. This study assessed the effects of stress induced by restricted movement on the morphology of ventral hippocampal CA1 neurons in male and female rats. Male and female Long Evans (LE) rats were subjected to restraint stress for 6 h every day for 25 days. One group of rats was used to study the dendritic morphology of CA1 ventral hippocampal neurons using the Golgi-Cox stain. A second group of rats was used to analyze learning and memory using the Morris water maze. Stressed female rats exhibited a decrease in the density of basilar dendritic spines, an increase in the number of apical dendritic intersections and deficits in spatial memory. There were no apparent effects of stress on male rats. Our data support previous findings of a dimorphic response to chronic stress and indicate that the ventral hippocampus is not particularly susceptible to the effects of stress.

Can Ayahuasca and sleep loss change sexual performance in male rats?

The ingestion of the beverage Ayahuasca usually occurs in religious ceremonies that are performed during the night leading to sleep deprivation. The purpose of the present study was to characterize the acute effects of Ayahuasca upon the sexual response of sleep deprived male rats. One group of sexually experienced male Wistar rats were submitted to a paradoxical sleep deprivation (PSD) protocol for 96h, while another group spent the same amount of time in the home cage (CTRL). After this period, either saline or Ayahuasca drink (250, 500 and 1000µgmL(-1)) was administered by gavage and sexual behavior and hormonal concentrations were measured. Ayahuasca alone significantly decreased sexual performance at all doses. However, in sleep deprived rats, the lower dose increased sexual performance while the intermediate dose produced a detrimental effect on sexual response compared to the CTRL rats at the same dose. Regarding the hormonal analyses, a lower testosterone concentration was observed in sleep-deprived saline rats in relation to the CTRL group. Progesterone was significantly lower only in PSD rats at the dose 500µgmL(-1) compared with CTRL-500µgmL(-1) group. Corticosterone was unchanged among the groups evaluated. Our results suggest that Ayahuasca intake markedly impaired sexual performance alone, but, when combined with sleep deprivation, had significant, but heterogeneous, effects on male sexual response.

Sodium fluoride does not alter sperm production or sperm morphology in rats

The aim of the present study was to evaluate the effects of sodium fluoride (NaF) on the male reproductive system. Adult male rats were exposed to NaF in drinking water for 30 days at three concentrations: 1.54 (control, tap water), 50 and 100 ppm. Body and organ weights, daily sperm production, sperm number and morphology were investigated. No difference was observed on the sperm number and morphology among the groups, as well as body weight and organ absolute and relative weights. Overall, despite the presence of a mild degree of dental fluorosis in the higher dose group, the results indicated that exposure to NaF at the doses used in the present study did not adversely affect sperm production and morphology of male rats.