Development In Female Rats Research Articles

Investigation of the Relationship Between Brown HT Dye Exposure and Mammary Tumor Development in Female Rats: An Assessment of the Potential Risk of Breast Cancer

Investigation of the Relationship Between Brown HT Dye Exposure and Mammary Tumor Development in Female Rats: An Assessment of the Potential Risk of Breast Cancer

High Carbohydrate, Fat, and Protein Diets Have a Critical Role in Folliculogenesis and Oocyte Development in Rats.

To date, there is no comparative data on the effects of carbohydrates, fat, and proteins, which are macronutrients, on female reproductive functions. Therefore, in this study, we investigated the effects of diets enriched with carbohydrates, fats, and proteins on folliculogenesis and oocyte development in female rats. 21-day-old rats that were just weaned were divided into 4 groups: control, carbohydrate, fat, and protein. The control group was fed with standard chow and the carbohydrate, fat, and protein groups were fed diets enriched with 75% carbohydrate, 60% fat, and 50% protein for 11 weeks, respectively. It was found that high-fat and high-protein diets caused an increase in the estrous cycle length compared to carbohydrate group (p < 0.05). Graafian follicle number decreased in the protein group compared to the control (p < 0.05). However, the atretic follicle number was higher in the fat group compared to the control group (p < 0.05). In the carbohydrate group, Zp1 was found to be lower than the control and protein groups, Zp2 was found to be lower than the control, and Zp3 was found to be lower than the fat group (p < 0.05). While BMP15 was similar between groups (p > 0.05), GDF9 was lower in all diet groups compared to the control (p < 0.05). Foxo3a was lower in the protein group compared to carbohydrate and control (p < 0.05). GAS2 was found to be higher in the control group than the fat group, and higher in the carbohydrate group than the fat and protein groups (p < 0.05). FSH, LH, Progesterone, and E2 levels were higher in all three diet groups than in the control (p < 0.05). Also, significant differences were observed between the groups regarding adiponectin, resistin, and leptin levels. Taken together, high carbohydrate, fat, and protein intake are associated with impairment of the menstrual cycle, depletion of the developing follicle types, and altered expression of folliculogenesis-specific genes and hormones. Therefore, long-term macronutrient diets may result in shortened reproductive periods and reduced fertilization potential in females in the long run.

The significance of light chronodestruction in the development of the embryotoxic effect in the experiment

Objective. To assess the significance of light chronodestruction in the development of the embryotoxic effect in the experiment. Materials and methods. The experiment was conducted on 60 female rats of the Wistar line. To assess the significance of chronodestruction in the development of embryotoxic effect, the uterus was isolated in the experiment, in which the number of implantation sites, the total number of embryos, the number of live and dead embryos, and the number of resorptions were estimated. The number of corpus luteum in the harvested ovaries was estimated. In addition, the mean embryo weight (g) and mean craniocaudal size (mm) were recorded. Indicators of embryotoxic effects of light deprivation were determined by pre- and post-implantation death, which was calculated in accordance with methodological recommendations. Results. Exposure to light deprivation reduces the number of implantation sites as of 7th, 14th and 21st days by 1,5-1,8 times, the total number of embryos by 1,6-1,8 times, the number of living embryos by 2,2-9 times and increases the number of dead embryos as of 14th and 21st days by 4-5,5 times, the number of resorptions – 1,6-11 times. The average craniocaudal size (mm) of embryos in experimental animals was recorded below control values by 1,5 times, 1,3 and 3,7 times by 7th, 14th, 21st days respectively. In females exposed to light deprivation, there was a significant increase in pre-implantation mortality by 35-41,8 times and post-implantation mortality by 7,2-20,4 times compared to the control. Conclusion. Light deprivation may have a negative effect on pregnancy and fetal development in female rats, which is confirmed by an increase in pre- and post-implantation mortality.

The Regulatory Effect of Eugenol on FSHR, LHCGR, and ER Expression during Follicular Development in Female Rats With Ovarian Torsion

Objectives: This study aimed to investigate the role of Eugenol in regulating the expression of FSH receptor (FSHR), human luteinizing hormone choriogonadotropin receptor (LHCGR), and estrogen receptor (ER) during follicular development in female rat ovarian torsion. Materials and Methods: In this experimental study, 48 female rats were randomly assigned to 4 groups, including G1 (i.e., sham), G2 (i.e., ovarian torsion/detorsion group), G3 (i.e., ovarian torsion/detorsion group treated with 30 mg/kg of eugenol), G4 (i.e., healthy group treated with 30 mg/kg of eugenol). After covering a treatment period of ten days, the ovarian tissue was collected for the histological analysis, the measurement of ER, FSHR, and LHCGR expression, as well as the assessment of testosterone, LH, FSH, and estrogen levels in blood serum. Results: Histological evaluation revealed the damage to ovarian tissue, the reduced oocyte, and the granulosa cell diameter in the torsion/detorsion group. However, the treatment with eugenol mitigated this damage. Eugenol administration increased the levels of estrogen, LH, and FSH, but it decreased the testosterone levels in the treated group. Moreover, the expression of ER, FSHR, and LHCGR was upregulated in the treated groups. Administration of eugenol was associated with an enhanced fertility. Conclusions: It was concluded that eugenol administration may have been effective in protecting the ovarian tissue from the damage caused by torsion/detorsion. Furthermore, eugenol was found to have the potential to modulate hormonal profiles and regulate the expression of ER, FSHR, and LHCGR, thereby contributing to an increased fertility.

Effects of decoction of Angelica Sinensis, Zingiberis Rhizoma Recens, and mutton on physiology and biochemistry of Sprague Dawley female rats with spleen-kidney Yang deficiency.

To examine the effects of each dose of decoction of Angelica sinensis (Dang gui), Zingiberis Rhizoma Recens (Sheng jiang), and mutton (DAZM) on the physiological and biochemical indexes of female rats with spleen-kidney Yang deficiency (SKYD) through 30-day feeding of DAZM, and to evaluate the tonifying effect of DAZM combined with the system of benefit damage index-general score (BDI-GS). Sprague Dawley (SD) rats were administered adenine and senna water to establish a SKYD model. The rats were then allocated to 4 groups at random: Model group, and L group, 4.2 g/kg, M group, 8.4 g/kg and H group, 16.8 g/kg. In addition, the group of normal feeding with unlimited diet was set as N group. Blood samples were taken to detect the relevant physiological and biochemical indexes. For organ coefficient analysis, 10 kinds of organ tissues were dissected and weighed. The tonifying effect of DAZM was discussed according to the BDI-GS system. During the modeling, the weight of rats in the normal group displayed a marked growth trend, and the weight of the model group was markedly lower than that of the normal group. After feeding the rats DAZM at a low, intermediate, and high dose, the anal temperature of rats in each group continued to rise, and finally remained basically the same as that of normal rats. Hematological and urine examinations revealed that the urea nitrogen and creatinine (CRE) of the model group and the experimental group were markedly higher than those of the normal group, and there were marked differences. After intragastric administration of DAZM, E2 increased markedly. The BDI-GS values of the liver, spleen, lung, kidney, brain, ovary, and adrenal gland of female rats in the 3 administration groups of DAZM were >1, and the total cumulative GS value of each organ of female rats was more than 10. The decoction of DAZM has no obvious effect on the growth, metabolism, and development of female rats with SKYD, causes no obvious damage to organs, and has a certain reparative effect on the kidney damage caused by SKYD.

Reproductive and endocrine effects of artemisinin, piperaquine, and artemisinin-piperaquine combination in rats

Background:The WHO recommends artemisinin-based combination regimens for uncomplicated Plasmodium falciparum malaria. One such combination is artemisinin-piperaquine tablets (ATQ). ATQ has outstanding advantages in anti-malarial, such as good efficacy, fewer side effects, easy promotion and application in deprived regions. However, the data about the reproductive and endocrine toxicity of ATQ remains insufficient. Thus, we assessed the potential effects of ATQ and its individual components artemisinin (ART) and piperaquine (PQ) on the reproductive and endocrine systems in Wistar rats.Methods:The unfertilized female rats were intragastric administrated with ATQ (20, 40, and 80 mg/kg), PQ (15, 30, and 60 mg/kg), ART (2.5, 5, and 10 mg/kg), or water (control) for 14 days, respectively. The estrous cycle and serum levels of estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), prostaglandin (PG), and adrenocorticotropic hormone (ACTH) were determined. The weights of the kidney, adrenal gland, uterus, and ovaries were measured. The histopathological examinations of the adrenal gland, ovary, uterus, and mammary gland were performed.Results:Compared with the control group, there were no significant differences in the examined items of female rats in the ART groups, including general observation, estrous cycle, hormonal level, organ weight, and histopathological examination. The estrous cycle of female rats was disrupted within 4–7 days after ATQ or PQ administration, and then in a persistent dioestrus phase. At the end of administration, ATQ and PQ at three doses induced decreased PG, increased ACTH, increased adrenal weight and size, and pathological lesions in the adrenal gland and ovary, including vasodilation and hyperemia in the adrenal cortex and medulla as well as hyperplasia and vacuolar degeneration, ovarian corpus luteum surface hyperemia, numerous but small corpus luteum, and disordered follicle development. But the serum levels of E2, FSH, LH, and PRL did not change obviously. These adverse effects in ATQ or PQ treated rats could not completely disappear after 21 days of recovery.Conclusion:Based on the results of this study, ART had no obvious reproductive and endocrine effects on female rats, while ATQ and PQ caused adrenal hyperplasia, increased ACTH, decreased PG, blocked estrus, corpus luteum surface hyperemia, and disrupted follicle development in female rats. These events suggest that ATQ and PQ may interfere with the female reproductive and endocrine systems, potentially reducing fertility.

The effect of ChAdOx1 nCov-19 vaccine on arterial thrombosis development and platelet aggregation in female rats

ChAdOx1 nCoV-19 adenoviral vector vaccine (ChAd) against coronavirus disease 2019 has been associated with vaccine-induced thrombosis and thrombocytopenia (VITT), especially in young women who have presented with unusual localized thrombosis after receiving the vaccine. The pathogenesis of VITT remains incompletely understood. We tried to provide new insights into mechanisms underlying this phenomenon in the model of arterial thrombosis electrically induced in the carotid artery of female rats. At 28 days post-vaccination, ChAd induced SARS-CoV-2-specific neutralizing antibody responses in all animals. The analysis of the blood vessel/thrombus area showed slight luminal narrowing of the carotid artery with extravasation of blood in vaccinated rats. These small changes were not accompanied by differences in thrombus weight and composition. The vaccinated animals presented a slight increase (by around 14–24%) in platelet aggregation. ChAd did not significantly affect blood coagulation, platelet counts, and their activation markers. Unaffected thrombus formation, the lack of thrombocytopenia and all the measured blood and hemostasis parameters that predominantly stayed unchanged, indicate that the ChAd does not increase the risk of arterial thrombosis development in female rats.

Sex‐ and Time‐Dependent Differences in Glutamate Receptor Subunit (GLUN1) in the Rat Rostral Ventrolateral Medulla

The cardioprotective effects of ovarian hormones are evident by the fact that women have a lower risk of cardiovascular disease compared to men, at least until menopause, at which time the relative risks reverse. Several studies have also demonstrated the importance of ovarian hormones in the regulation of sympathetic outflow, potentially via actions in the rostral ventrolateral medulla (RVLM), a brain region critical to sympathetic outflow and blood pressure. However, the time course and mechanisms of sex‐dependent changes in excitation of RVLM neurons have not been fully characterized. Therefore, the purpose of this study was to compare glutamate receptor (GluN1) subunit expression in the RVLM of male and female rats, focusing specifically on ages of development in female rats which precede the onset of the estrous cycle (4 wks old) versus when the estrous cycle is fully established (8 wks old). We hypothesized that eight week‐old female rats would exhibit reduced GluN1 compared to four week‐old females. In contrast, we also predicted that eight week‐old male rats would have higher GluN1 compared to four week‐old males. To test our hypothesis, we obtained brain punches from RVLM subregions of male and female Sprague‐Dawley rats (n=3 ea; 4 and 8 wks old) based on their anatomical location relative to the facial nucleus (FN). Punches were processed for western blotting of GluN1 subunit in four subregions: FN‐480; FN‐240; FN+240 and FN+480. At FN‐480, GluN1 was lower in eight week‐compared to four week‐old female rats (0.67 ± 0.11 vs. 1.11 ± 0.08 protein/GAPDH, respectively). In contrast, at FN‐480, eight week‐old male rats exhibited increased NR1 expression compared to four week old males (1.05 ± 0.06 vs. 0.65 ± 0.10; protein/GAPDH, respectively p&lt;0.05). These results suggest that lower levels of ovarian hormones in prepubescent females may increase the excitability of RVLM neurons and lead to greater sympathoexcitation, which then decrease with the onset of the reproductive cycle. The absence of ovarian hormones in males (perhaps coupled with a lack of regular exercise) may exacerbate RVLM excitability, leading to greater sympathoexcitation in sedentary males. Collectively, these data suggest that ovarian hormones exert cardioprotective effects via actions in the RVLM, reducing sympathetic outflow and contributing to a lower incidence of cardiovascular disease in women of reproductive age.Support or Funding InformationHL096787‐08; AHA25810010

Neonatal exposure to bisphenol A advances pubertal development in female rats

Neonatal exposure to bisphenol A (BPA) is hypothesized to advance pubertal development. However, the effects of neonatal BPA exposure on pubertal development has not been described. In this study, female Sprague-Dawley rats were exposed to 0.05, 0.5, 5, or 10 mg·kg-1 ·day-1 BPA, or corn oil vehicle alone from postnatal day 1 (PND1) to PND10 via subcutaneous injection. We evaluated day of vaginal opening (DVO), ovarian morphology, serum hormone concentrations, and hypothalamic expression of Gnrh1 and Kiss1 in female rats at PND35. DVO was significantly advanced in rats exposed to 5 and 10 mg·kg-1 ·day-1 BPA. Serum hormone concentrations increased as BPA dose increased. Additionally, hypothalamic Gnrh1 and Kiss1 expression were increased with BPA exposure; rats exposed to 10 mg·kg-1 ·day-1 BPA had significantly upregulated hypothalamic Gnrh1 and Kiss1 expressions in terms of both messenger RNA and protein levels. Our results suggest that exposure to a 10 mg·kg-1 ·day-1 dose of BPA might advance pubertal development significantly. In addition, within the range of 0 to 10 mg·kg-1 ·day-1 , neonatal exposure to BPA may affect pubertal development in a dose-dependent manner.

Vitamin D3 supplementation influences ovarian histomorphometry and follicular development in prepubertal albino rats

Objective: To evaluate the development of ovarian follicles in female albino rats following vitamin D3 supplementation. Methods: Eighteen prepubertal female albino rats, aged 3-4 weeks, weighing (70.25±9.16) g, were assigned to three groups (n=6 in each group). Group A was treated with 5.00 mL/kg of distilled water and served as the control group, group B was treated with 0.025 mg/kg of vitamin D3 dissolved in distilled water, and group C was treated with 0.125 mg/kg of vitamin D3 dissolved in distilled water. All treatments were administered orally, twice weekly for 28 days. Blood and ovaries were harvested under anaesthesia. Serum vitamin D3 levels were determined by using spectrophotometric method. Ovaries were processed for histology and every10th hematoxylin and eosin stained-section was selected for histomorphometry. The number of follicles at each developmental stage was estimated.Results: Both 0.025 mg/kg and 0.125 mg/kg of vitamin D3 significantly increased serum concentrations of vitamin D3 and calcium (P<0.05), but did not alter inorganic phosphorus concentration (P>0.05). The control group had fewer growing follicles (primary, secondary and antral follicles) and more non-growing follicles (primordial and atretic follicles) when compared with the vitamin D3-supplemented groups (P<0.05). Vitamin D3 at 0.025 mg/kg significantly increased antral follicles and corpora lutea counts (P<0.05). Vitamin D3 at 0.125 mg/kg significantly increased total, primordial and atretic follicles counts (P<0.05), but significantly decreased primary, secondary, antral follicles count, ovarian weight, relative ovarian weight, and ovarian surface area when compared with the control group and rats treated with 0.025 mg/kg of vitamin D3 (P<0.05).Conclusions: Vitamin D3 supplementation at 0.025 mg/kg can enhance optimal ovarian follicle recruitment and development in female rats.

Adverse effects of subchronic exposure to cooking oil fumes on the gonads and the GPR30-mediated signaling pathway in female rats

BackgroundCooking oil fumes (COFs) are composed of particulate matter, polycyclic aromatic hydrocarbons, volatile organic compounds, aldehydes, and ketones, and are currently a global health concern. Some agents in COFs are mutagenic and carcinogenic. However, only a few reports have addressed the hazardous effects of COF exposure on the female reproductive system. In this study, we explored the effects of subchronic exposure to COFs on female gonads in vivo and the possible involvement of the G-protein-coupled receptor 30 signaling pathway.MethodsCOFs were generated by heating commercially available canola oil in an iron pot. Adult female Wistar rats at 2 months of age were exposed to COFs at 32 mg/m3 for 0, 0.5, 1, 2, or 4 h/day for 56 days. The estrous cycle in rats was studied twice at 7:00 a.m. and 7:00 p.m. on the 43rd treatment day until the current estrous cycle was complete. The rat body weight was measured before the experiment and at day 56 post-exposure. At the end of the experiment, rat blood was collected for gonadal hormone assay, and ovaries were collected for histology and mRNA isolation. The mRNA levels of GPR30, EGFR, STAT3, and ERK were determined by quantitative RT-PCR.ResultsAt a concentration of 32.21 ± 5.11 mg/m3, COF exposure extended the estrous cycle in rats, and ovary coefficient decreased. COFs showed various effects on the sex hormone levels and follicles, depending on its exposure level. Exposure to COFs led to the changes in mRNA levels of the G-protein-coupled receptor 30 (GPR30), epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3), and extracellular signal-regulated kinase (ERK).ConclusionThis study indicated that cooking oil fume exposure disrupted the estrous cycle, sex hormone patterns, and follicle development in female rats in a dose-dependent manner. These adverse effects of cooking oil fumes on female reproductive health were correlated with the G-protein-coupled receptor 30-mediated signaling pathway.HighlightsSubchronic exposure to COFs for 56 days had gonadal toxicity in female rats, that disrupted the estrous cycle, sex hormone patterns, and follicle development in a dose-dependent manner.Reproductive endocrine disruption might be one of the female gonadotoxicity mechanisms of COFs.These adverse effects of COFs on female reproductive health were correlated with the GPR30-mediated signaling pathway.

Exposure of BPA and its alternatives like BPB, BPF, and BPS impair subsequent reproductive potentials in adult female Sprague Dawley rats

Bisphenol A (BPA) and its alternatives are extensively used in household and industrial products. BPA and its alternatives have affinity for estrogen receptors and mimic its actions. The present study aims to examine the comparative effects of BPA and its alternatives bisphenol B (BPB), bisphenol F (BPF), and bisphenol S (BPS) on the reproductive health in adult female rats. One hundred and seventy post-weaning female rats (90 ± 25) were divided into 17 groups and assigned for different treatments. Control and treated groups were injected with concentrations of 50–500 µg/ml and 5–50 mg/kg of BPA, BPB, BPF, and BPS for 28 days. The results showed adverse morphological and histopathological alterations in rat ovaries in all treated groups. A remarkable decrease was observed in antral and corpus luteum follicles while rise in atretic and cystic follicles in the ovaries of BPA and its alternatives 5 and 50 mg/kg treated groups when compared with control. Significant decrease in catalase (CAT), super oxidase (SOD), and peroxidase (POD) levels was noted while increase in the values of thiobarbituric acid reactive substance (T-BARS) and reactive oxygen species (ROS) was observed when BPA and its alternatives groups were compared with the control. Hormones were also observed with alterations in their concentrations when treated groups were compared with the control. The current data suggest that BPA and its alternatives exposure during the pre-pubertal stage have the potential to induce oxidative stress and histopathological changes during follicular development in female rats.

Ad libitum feeding triggers puberty onset associated with increases in arcuate Kiss1 and Pdyn expression in growth-retarded rats.

Increasing evidence shows that puberty onset is largely dependent on body weight rather than chronological age. To investigate the mechanism involved in the energetic control of puberty onset, the present study examined effects of chronic food restriction during the prepubertal period and the resumption of ad libitum feeding for 24 and 48 h on estrous cyclicity, Kiss1 (kisspeptin gene), Tac3 (neurokinin B gene) and Pdyn (dynorphin A gene) expression in the hypothalamus, luteinizing hormone (LH) secretion and follicular development in female rats. When animals weighed 75 g, they were subjected to a restricted feeding to retard growth to 70–80 g by 49 days of age. Then, animals were subjected to ad libitum feeding or remained food-restricted. The growth-retarded rats did not show puberty onset associated with suppression of both Kiss1 and Pdyn expression in the arcuate nucleus (ARC). 24-h ad libitum feeding increased tonic LH secretion and the number of Graafian and non-Graafian tertiary follicles with an increase in the numbers of ARC Kiss1- and Pdyn-expressing cells. 48-h ad libitum feeding induced the vaginal proestrus and a surge-like LH increase with an increase in Kiss1-expressing cells in the anteroventral periventricular nucleus (AVPV). These results suggest that the negative energy balance causes pubertal failure with suppression of ARC Kiss1 and Pdyn expression and then subsequent gonadotropin secretion and ovarian function, while the positive energetic cues trigger puberty onset via an increase in ARC Kiss1 and Pdyn expression and thus gonadotropin secretion and follicular development in female rats.

Effect of Methomyl on Fetal Development in Female Rats

Effect of Methomyl on Fetal Development in Female Rats

4-Nitrophenol (PNP) inhibits the expression of estrogen receptor β and disrupts steroidogenesis during the ovarian development in female rats

4-nitrophenol (PNP), isolated from diesel exhaust particles, has estrogenic and anti-androgenic activities, and affects the hypothalamus-pituitary-gonad axis in male rats. However, the effect of PNP on the reproduction of the female rats is still unknown. The aim of the study was to investigate the effect of neonatal PNP exposure on the ovarian function of female rats. The neonatal female rats were exposed to PNP (10 mg/kg, subcutaneously injection), the ovary and serum samples were collected at postnatal day (PND) 7, 14 and 21. The results showed that the ratio of primordial and primary follicles increased whereas the ratio of antral follicles decreased in the PNP treated ovaries at PND21. Even though no abnormality was observed in cyclicity, there was a significantly delayed timing of vaginal opening in PNP treated rats. The ovarian expression of steroidogenic enzymes including StAR, P450scc, P450c17 and P450arom increased at PND14 in the PNP treated rats compared with the control rats. In consistent with the gene expression, the concentration of estradiol-17β showed the similar pattern. However, PNP exposure failed to cause any significant change in the expression of steroidogenic enzymes in cultured neonatal ovaries. Furthermore, PNP suppressed the expression of estrogen receptor β (ERβ), but not estrogen receptor α (ERα), in cultured ovaries or developmental ovaries. These results suggested that PNP might directly affect the expression of ERβ in the rat ovaries, resulting in the disrupted steroidogenesis during ovarian development and the delayed puberty.

Evidence of Absence: Estrogenicity Assessment of a New Food-Contact Coating and the Bisphenol Used in Its Synthesis.

Consumer concerns about exposure to substances found in food contact materials with estrogenic activity (EA) have created substantial demand for alternatives. We assessed the potential EA of both a new bisphenol monomer used to synthesize polymeric coatings for metal food-contact applications and the nonintentionally added substances (NIAS) that may migrate into food. We evaluated tetramethyl bisphenol F (TMBPF) using in vitro and in vivo assays. We extracted the polymeric coating using food simulants ethanol (50% v/v) and acetic acid (3% w/v) and measured migration using tandem liquid chromatography (LC)/mass spectrometry (MS) and LC time-of-flight MS for TMBPF and NIAS, respectively. We also tested migrants for EA using the E-SCREEN assay. TMBPF did not show estrogenic activity in the uterotrophic assay and did not alter puberty in male and female rats or mammary gland development in female rats. Neither TMBPF nor the migrants from the final polymeric coating increased proliferation of estrogen-sensitive MCF7 cells. TMBPF did not show estrogen-agonist or antagonist activity in the estrogen receptor-transactivation assay. TMBPF migration was below the 0.2 parts per billion detection limit. Our findings provide compelling evidence for the absence of EA by TMBPF and the polymeric coating derived from it and that human exposure to TMBPF would be negligible.

P.7.c.002 - Acute perinatal hypoxia: repeated observations of physical and motor development in albino rat pups and outcomes of synthetic analog of ACTH4−10 administration

Caffeine is the psychostimulant most consumed worldwide. In moderate doses, it affords a beneficial effect in adults and upon aging, but has a deleterious effect during brain development. We now tested if caffeine consumption by rats (0.1, 0.3, 1.0 g/L in the drinking water, only during active cycle and weekdays) during adulthood could revert the potentially negative effects of caffeine during early life. Thus, we compared caffeine intake starting 15 days before mating and lasting either up to weaning (development) or up to adulthood, on behavior and synaptic proteins in male and female rats. Recognition memory was impaired only in female rats receiving caffeine (0.3 and 1.0 g/L) during development, coincident with increased proBDNF and unchanged BDNF levels in the hippocampus. Caffeine in both treatment regimens caused hyperlocomotion only in male rats, whereas anxiety-related behavior was attenuated in both sexes by caffeine (1.0 g/L) throughout life. Both caffeine treatment regimens decreased GFAP (as an astrocyte marker) and SNAP-25 (as a nerve terminals marker) in the hippocampus from male rats. TrkB receptor was decreased in the hippocampus from both sexes and treatment regimens. These findings revealed that caffeine intake during a specific time window of brain development promotes sex-dependent behavioral outcomes related to modification in BDNF signaling. Furthermore, caffeine throughout life can overcome the deleterious effects of caffeine on recognition memory during brain development in female rats.

Prenatal Alcohol Exposure and Pair Feeding Differentially Impact Puberty and Reproductive Development in Female Rats: Role of the Kisspeptin System.

Reproductive maturation is initiated with the onset of puberty, which activates the hypothalamic-pituitary-gonadal axis and coincidences with increased expression of the hormone kisspeptin within the hypothalamus. Maturational events are sensitive to environmental factors, including alcohol, which is known to delay reproductive development. We hypothesized that, similar to alcohol's adverse effects during reproductive maturation, prenatal alcohol exposure (PAE) would alter pubertal markers, sex hormone profiles, and kisspeptin expression in the hypothalamus. Female offspring from control (C), pair-fed (PF), and PAE groups were sacrificed prior to puberty onset (postnatal day [PND] 30), during puberty [PND 35], or in adulthood [PND 65]. Estradiol (E2 ), progesterone (P4 ), prolactin, and luteinizing hormone levels, and Kiss1 mRNA expression were measured in the arcuate (ARC) and anteroventral periventricular (AVPV) nuclei of the hypothalamus. Pubertal markers (vaginal opening [VO], uterus/body wt ratio) were assessed. Our findings indicate that (i) PAE inhibits the expected increases in E2 levels with age and delays maturational increases of P4 levels; (ii) PAE and pair feeding have similar adverse effects on VO and uterus/body wt ratio; (iii) differential relationships between PRL and P4 suggest that different mechanisms may underlie delayed maturation in PAE and PF; that is, PF females have low PRL levels and no increase in P4 with age, whereas PAE animals, despite low PRL, show the expected age-related increase in P4 ; and (iv) there is higher mean density of Kiss1 mRNA in the ARC of adult PAE females and altered Kiss1 expression in the AVPV of both PAE and PF females. PAE and pair feeding have some overlapping but important differential effects on hormonal profiles and Kiss1 mRNA expression during reproductive development. Preadolescent alterations in Kiss1 expression in the AVPV and ARC, which may change the balance of function in these 2 nuclei, may differentially contribute to delayed reproductive maturation in PAE and PF compared to C females.

Estrogenic Compounds Impair Primordial Follicle Formation by Inhibiting the Expression of Proapoptotic Hrk in Neonatal Rat Ovary.

Exposure to endocrine-disrupting chemicals (EDCs) during fetal and neonatal periods can have toxic effects that are irreversible and last a lifetime. However, the mechanism underlying this phenomenon is still unknown. Here, we show the effect of 17alpha-ethynyl estradiol (EE) on the development of the primordial follicle during early ovarian development in female rats. Microarray analysis revealed the down-regulation of Hrk, an activator of apoptosis, in neonatal ovaries exposed to EE. Real-time PCR analysis also showed a decrease of Hrk mRNA expression in ovaries treated with EE both in vitro and in neonatal rats. An immunostaining assay showed that HRK protein and cleaved caspase 3 colocalize in the oocytes at Postnatal Day 1 (PND1). The EE-exposed ovaries had a reduced number of oocytes positive for TUNEL staining compared to control ovaries at PND1. Abnormal follicle formation of EE-exposed ovaries was observed at PND7 and PND21. A TUNEL staining assay revealed that Hrk depletion reduced the number of apoptotic oocytes. In addition, down-regulation of Hrk mRNA expression was observed in ovaries treated with other estrogenic chemicals. We propose a model in which EE inhibits oocyte apoptosis in the neonatal ovary by suppressing the expression of Hrk, thereby disrupting follicle formation and ovary function.

新生期17α-エチニルエストラジオール(EE)曝露による遅発影響の最小影響量が雌ラットの生殖能力および胚胎児の発生に及ぼす影響

新生期17α-エチニルエストラジオール(EE)曝露による遅発影響の最小影響量が雌ラットの生殖能力および胚胎児の発生に及ぼす影響