Immature Sprague-Dawley Rats Research Articles

Mdivi-1 alleviates ferroptosis induced by hypoxia combined with propofol in HT22 cells by inhibiting excessive mitophagy.

Pediatric postoperative cognitive dysfunction (POCD) is a prevalent complication following anesthesia and surgery. Hypoxia and propofol are the primary risk factors contributing to pediatric POCD. Our previous in vivo animal research has demonstrated that cognitive dysfunction in immature Sprague-Dawley (SD) rats, induced by hypoxia combined with propofol (HCWP), is closely associated with hippocampal neuron ferroptosis. In vivo transcriptome sequencing and KEGG functional analysis revealed significant enrichment of the mitophagy pathway. To further elucidate the relationship between mitophagy and ferroptosis, HT22 cells were selected to construct an in vitro HCWP model. Our findings indicate that HCWP activates excessive mitophagy in HT22 cells, leading to decreased mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) burst, mitochondrial fragmentation, and the induction of ferroptosis. To explore this causal relationship further, we employed Mdivi-1, a mitophagy inhibitor. Notably, low-dose Mdivi-1 (10 µM) effectively suppressed excessive mitophagy in HT22 cells, improved mitochondrial function and morphology, and mitigated markers associated with ferroptosis. The mechanism by which Mdivi-1 alleviates HCWP-induced ferroptosis in HT22 cells is likely due to its inhibition of excessive mitophagy, thereby promoting mitochondrial homeostasis. Our study suggests that mitophagy may be an upstream event in HCWP-induced ferroptosis in HT22 cells. Consequently, targeted regulation of mitophagy by Mdivi-1 may represent a promising approach to prevent cognitive dysfunction following HCWP exposure.

Corrigendum to: "Juvenile Toxicity Rodent Model to Study Toxicological Effects of Bisphenol A (BPA) at Dose Levels Derived From Italian Children Biomonitoring Study".

Bisphenol A (BPA) is a plasticizer with endocrine disrupting properties particularly relevant for children health. Recently BPA has been associated with metabolic dysfunctions but no data are yet available in specific, long-term studies. This study aimed to evaluate BPA modes of action and hazards during animal juvenile life-stage, corresponding to childhood. Immature Sprague-Dawley rats of both sexes were orally treated with 0 (vehicle only-olive oil), 2, 6, and 18 mg/kg bw per day of BPA for 28 days, from weaning to sexual maturity. Dose levels were obtained from the PERSUADED biomonitoring study in Italian children. Both no-observed-adverse-effect-level (NOAEL)/low-observed-adverse-effect-level (LOAEL) and estimated benchmark dose (BMD) approaches were applied. General toxicity, parameters of sexual development, endocrine/reproductive/functional liver and kidney biomarkers, histopathology of target tissues, and gene expression in hypothalamic-pituitary area and liver were studied. No mortality or general toxicity occurred. Sex-specific alterations were observed in liver, thyroid, spleen, leptin/adiponectin serum levels, and hypothalamic-pituitary gene expression. Thyroid homeostasis and liver were the most sensitive targets of BPA exposure in the peripubertal phase. The proposed LOAEL was 2 mg/kg bw, considering as critical effect the liver endpoints, kidney weight in male and adrenal histomorphometrical alterations and osteopontin upregulation in female rats. The BMD lower bounds were 0.05 and 1.33 mg/kg bw in males and females, considering liver and thyroid biomarkers, respectively. Overall, BPA evaluation at dose levels derived from children biomonitoring study allowed to identify sex-specific, targeted toxicological effects that may have significant impact on risk assessment for children.

MicroRNA‐9‐5p alleviates blood–brain barrier damage and neuroinflammation after traumatic brain injury

The level of microRNA‐9‐5p (miRNA‐9‐5p) in brain tissues is significantly changed after traumatic brain injury (TBI). However, the effect of miRNA‐9‐5p for brain function in TBI has not been elucidated. In this study, a controlled cortical impact model was used to induce TBI in Sprague–Dawley rats, and an oxygen glucose deprivation model was used to mimic the pathological state in vitro. Brain microvascular endothelial cells (BMECs) and astrocytes were extracted from immature Sprague–Dawley rats and cocultured to reconstruct blood–brain barrier (BBB) in vitro. The results show that the level of miRNA‐9‐5p was significantly increased in brain tissues after TBI, and up‐regulation of miRNA9‐5p contributed to the recovery of neurological function. Up‐regulation of miRNA‐9‐5p with miRNA agomir may significantly alleviate apoptosis, neuroinflammation, and BBB damage in rats after TBI. Moreover, a dual luciferase reporter assay confirmed that miRNA‐9‐5p is a post‐transcriptional modulator of Ptch‐1. In in vitro experiments, the results confirmed that up‐regulation of miRNA‐9‐5p with miRNA mimic alleviates cellular apoptosis, inflammatory response, and BBB damage mainly by inhibiting Ptch‐1. In addition, we found that the activation of Hedgehog pathway was accompanied by inhibition of NF‐κB/MMP‐9 pathway in the BMECs treated with miRNA‐9‐5p mimic. Taken together, these results indicate that up‐regulation of miRNA‐9‐5p alleviates BBB damage and neuroinflammatory responses by activating the Hedgehog pathway and inhibiting NF‐κB/MMP‐9 pathway, which promotes the recovery of neurological function after TBI.

Androgens Modulate Rat Granulosa Cell Steroidogenesis.

Paracrine interactions between ovarian theca-interstitial cells (TICs) and granulosa cells (GCs) play an important role in the regulation of follicular steroidogenesis. Androgens serve as substrates for aromatization as well as affect GC function. This study evaluated the effects of co-culture of GC with TICs and the role of testosterone (T) and 5-alpha-dihydrotestosterone (DHT), and estradiol (E2) in modulation of GC expression of genes involved in the production of progesterone: 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (Hsd3b) and cholesterol side-chain cleavage (Cyp11). GCs obtained from immature Sprague-Dawley rats and were cultured in chemically defined media without or with TICs, DHT, or T. Hsd3b and Cyp11 transcripts were analyzed by qt-PCR. Co-culture of GCs with TICs stimulated Hsd3b and CYP11 expression in GCs. DHT and T induced a concentration-dependent upregulation of Hsd3b and CYP11 expression, as well as increased progesterone concentrations in spent media. E2 also increased expression of Hsd3b, and Cyp11. Effects of androgens were abrogated in the presence of an anti-androgen bicalutamide and the antiestrogen ICI 182780 (ICI). In conclusion, present findings demonstrate that androgens upregulate production of progesterone in GCs; these effects are likely due to a combination of direct action on androgen receptors and effects mediated by estrogen receptors.

Juvenile Toxicity Rodent Model to Study Toxicological Effects of Bisphenol A (BPA) at Dose Levels Derived From Italian Children Biomonitoring Study.

Bisphenol A (BPA) is a plasticizer with endocrine disrupting properties particularly relevant for children health. Recently BPA has been associated with metabolic dysfunctions but no data are yet available in specific, long-term studies. This study aimed to evaluate BPA modes of action and hazards during animal juvenile life-stage, corresponding to childhood. Immature Sprague-Dawley rats of both sexes were orally treated with 0 (vehicle only-olive oil), 2, 6, and 18 mg/kg bw per day of BPA for 28 days, from weaning to sexual maturity. Dose levels were obtained from the PERSUADED biomonitoring study in Italian children. Both no-observed-adverse-effect-level (NOAEL)/low-observed-adverse-effect-level (LOAEL) and estimated benchmark dose (BMD) approaches were applied. General toxicity, parameters of sexual development, endocrine/reproductive/functional liver and kidney biomarkers, histopathology of target tissues, and gene expression in hypothalamic-pituitary area and liver were studied. No mortality or general toxicity occurred. Sex-specific alterations were observed in liver, thyroid, spleen, leptin/adiponectin serum levels, and hypothalamic-pituitary gene expression. Thyroid homeostasis and liver were the most sensitive targets of BPA exposure in the peripubertal phase. The proposed LOAEL was 2 mg/kg bw, considering as critical effect the liver endpoints, kidney weight in male and adrenal histomorphometrical alterations and osteopontin upregulation in female rats. The BMD lower bounds were 0.05 and 1.33 mg/kg bw in males and females, considering liver and thyroid biomarkers, respectively. Overall, BPA evaluation at dose levels derived from children biomonitoring study allowed to identify sex-specific, targeted toxicological effects that may have significant impact on risk assessment for children.

In vivo characterization of a novel norepinephrine transporter PET tracer [18F]NS12137 in adult and immature Sprague-Dawley rats.

Norepinephrine modulates cognitive processes such as working and episodic memory. Pathological changes in norepinephrine and norepinephrine transporter (NET) function and degeneration of the locus coeruleus produce irreversible impairments within the whole norepinephrine system, disrupting cognitive processes. Monitoring these changes could enhance diagnostic accuracy and support development of novel therapeutic components for several neurodegenerative diseases. Thus, we aimed to develop a straightforward nucleophilic fluorination method with high molar activity for the novel NET radiotracer [18F]NS12137 and to demonstrate the ability of [18F]NS12137 to quantify changes in NET expression.Methods: We applied an 18F-radiolabeling method in which a brominated precursor was debrominated by nucleophilic 18F-fluorination in dimethyl sulfoxide. Radiolabeling was followed by a deprotection step, purification, and formulation of the radiotracer. The [18F]NS12137 brain uptake and distribution were studied with in vivo PET/CT and ex vivo autoradiography using both adult and immature Sprague-Dawley rats because postnatal NET expression peaks at 10-20 days post birth. The NET specificity for the tracer was demonstrated by pretreatment of the animals with nisoxetine, which is well-known to have a high affinity for NET.Results: [18F]NS12137 was successfully synthesized with radiochemical yields of 18.6±5.6%, radiochemical purity of >99%, and molar activity of >500 GBq/μmol at the end of synthesis. The in vivo [18F]NS12137 uptake showed peak standard uptake values (SUV) of over 1.5 (adult) and 2.2 (immature) in the different brain regions. Peak SUV/30 min and peak SUV/60 min ratios were calculated for the different brain regions of the adult and immature rats, with a peak SUV/60 min ratio of more than 4.5 in the striatum of adult rats. As expected, in vivo studies demonstrated uptake of the tracer in brain areas rich in NET, particularly thalamus, neocortex, and striatum, and remarkably also in the locus coeruleus, a quite small volume for imaging with PET. The uptake was significantly higher in immature rats compared to the adult animals. Ex vivo studies using autoradiography showed very strong specific binding in NET-rich areas such as the locus coeruleus and the bed nucleus of the stria terminalis, and high binding in larger grey matter areas such as the neocortex and striatum. The uptake of [18F]NS12137 was dramatically reduced both in vivo and ex vivo by pretreatment with nisoxetine, demonstrating the specificity of binding.Conclusions: [18F]NS12137 was synthesized in good yield and high molar activity and demonstrated the characteristics of a good radiotracer, such as good brain penetration, fast washout, and high specific binding to NET.

In vivo intrabursal administration of bioactive lipid sphingosine-1-phosphate enhances vascular integrity in a rat model of ovarian hyperstimulation syndrome.

Can the bioactive lipid sphingosine-1 phosphate (S1P) act as an endothelial barrier-enhancing molecule and, in turn, restore the vascular integrity and homoeostasis in a rat model of ovarian hyperstimulation syndrome (OHSS). In vivo administration of S1P may prevent the early onset of OHSS and decrease its severity. Although advances in the prediction and treatment of OHSS have been made, complete prevention has not been possible yet. S1P in follicular fluid from women at risk of developing OHSS are lower in comparison from women who are not at such risk and administration of S1P in an OHSS rat model decreases ovarian capillary permeability. We used an animal model that develops OHSS in immature Sprague-Dawley rats. The rats were randomly divided into three groups: the control group, which was injected with 10 IU of pregnant mare's serum gonadotropin (PMSG), and 10 IU ofhCG 48 h later; the OHSS group, which was injected with excessive doses of PMSG (50 IU/day) for four consecutive days, followed by hCG; and the OHSS + S1P group, which was injected with the same doses of PMSG and hCG as the OHSS group and then treated with 5 μl S1P (1 mM) under the bursa of both ovaries, whereas the other groups of animals received the S1P vehicle. Rats were killed by decapitation 48 h after the hCG injection for ovary, endometrium and blood collection. The ovaries were weighed and then used for subsequent assays, while the serum was used for hormone assays. One of the ovaries from each rat (n = 6) was used for Western immunoblot and the other for immunohistochemical analysis. Statistical comparisons between groups were carried out. S1P administration reduced the ovarian weight (P < 0.05), and decreased the concentration of serum progesterone in the OHSS group compared to the OHSS group without treatment (P < 0.001). The percentage of antral follicles in the OHSS group was lower than that in the control group. S1P increased the percentage of antral follicles (P < 0.05) and decreased the percentage of corpora lutea (P < 0.01) and cystic structures in the OHSS group (P < 0.05). S1P had no effect on the expression levels of the enzymes 3β-hydroxysteroid dehydrogenase (3βHSD) or cholesterol side-chain cleavage enzyme (P450scc), but reduced the levels of steroidogenic acute regulatory protein (StAR) in OHSS rat ovaries (P < 0.05). S1P decreased the endothelial (P < 0.05) and periendothelial (P < 0.01) cell area in OHSS rat ovaries. S1P restored the levels of N-cadherin and VE-cadherin proteins to control values. Furthermore, S1P enhanced the levels of claudin-5, occludin (P < 0.05) and sphingosine-1-phosphate receptor 1 (S1PR1) in OHSS (P < 0.01). In addition, no histological differences were found in endometrium between OHSS and S1P-treated OHSS animals. The results of this study were generated from an in vivo OHSS experimental model, which has been used by several authors and our group due to the similarity between the rat and human angiogenic systems. Further studies in patients will be needed to evaluate the effects of S1P in the pathogenesis of OHSS. These findings concern the pathophysiological importance of S1P in OHSS. More studies on the regulation of endothelial cell barrier function by S1P in reproductive pathological processes and its therapeutic application are required. N/A. This work was supported by grants from ANPCyT (PICT 2012-897), CONICET (PIP 5471), Roemmers and Baron Foundations, Argentina. The authors declare no conflicts of interest.

Does partial muscle reinnervation preserve future re-innervation potential?

Late revision nerve surgery for incomplete motor recovery due to partial reinnervation would improve muscle function if all muscle fibers were protected from developing denervation atrophy. Sixty immature Sprague-Dawley rats underwent the following tibial nerve manipulations (n = 15/group): group A, partial denervation (two thirds of nerve resected and the remaining one third crushed), revision repair at 8 months; group B, partial denervation; group C, complete denervation, immediate reconstruction; group D, complete denervation, reconstruction at 8 months; and group E, control. Final testing at 11 months included muscle force, weight, and histology. Muscle weight was significantly (P < 0.05) different among all groups (highest to lowest: E > B > C > A > D), and force was significantly lower in groups A and D compared with E. Muscle fiber cross-sectional area was statistically smaller in group A than in groups B, C, or E. Partial reinnervation still allowed substantial muscle recovery, but it did not preserve the non-innervated muscle fibers. Muscle Nerve 56: 1143-1148, 2017.

VEGF regulates hippocampal neurogenesis and reverses cognitive deficits in immature rats after status epilepticus through the VEGF R2 signaling pathway.

Epilepsy is the most common chronic disease in children, who exhibit a higher risk for status epilepticus (SE) than adults. Hippocampal neurogenesis is altered by epilepsy, particularly in the immature brain, which may influence cognitive development. Vascular endothelial growth factor (VEGF) represents an attractive target to modulate brain function at the neurovascular interface and is a double-edged sword in seizures. We used the lithium-pilocarpine-induced epilepsy model in immature Sprague-Dawley rats to study the effects of VEGF on hippocampal neurogenesis in the acute phase and on long-term cognitive behaviors in immature rats following status epilepticus (SE). VEGF correlates with cell proliferation in the immature brain after SE. By preprocessing VEGF in the lateral ventricles prior to the induction of the SE model, we found that VEGF increased the proliferation of neural stem cells (NSCs) and promoted the migration of newly generated cells via the VEGF receptor 2 (VEGFR2) signaling pathway. VEGF also inhibited cell loss and reversed the cognitive deficits that accompany SE. Based on our results, VEGF positively contributes to the initial stages of neurogenesis and alleviates cognitive deficits following seizures; moreover, the VEGF/VEGFR2 signaling pathway may provide a novel treatment strategy for epilepsy.

Sphingosine-1-phosphate restores endothelial barrier integrity in ovarian hyperstimulation syndrome.

Are follicular fluid (FF) sphingosine-1-phosphate (S1P) levels in patients at risk of developing ovarian hyperstimulation syndrome (OHSS) altered and in part responsible for the high vascular permeability observed in these patients. FF S1P levels are lower in FF from patients at risk of OHSS and treatment with S1P may reduce vascular permeability in these patients. Although advances have been made in the diagnosis, and management of OHSS and in basic knowledge of its development, complete prevention has proven difficult. A total of 40 FF aspirates were collected from patients undergoing ART. The women (aged 25-39 years old) were classified into a control group (n=20) or a group at risk of OHSS (n=20). The EA.hy926 endothelial cell line was used to assess the efffects of FF from patients at risk of OHSS with or without the addition of S1P. An animal model that develops OHSS in immature Sprague-Dawley rats were also used. Migration assays, confocal microscopy analysis of actin filaments, immunoblotting and quail chorioallantoic membrane (CAM) assays of in-vivo angiogenesis were performed and statistical comparisons between groups were made. The S1P concentration was significantly lower in FF from patients at risk of OHSS (P = 0.03). The addition of S1P to this FF decreased cell migration (P < 0.05) and prevented VE-cadherin phosphorylation in endothelial cells (P < 0.05). S1P in the FF from patients at risk of OHSS increased the levels of VE-cadherin (P < 0.05), N-cadherin (P < 0.05) and β-catenin (P < 0.05), and partially reversed actin redistribution in endothelial cells. The addition of S1P in FF from patients at risk of OHSS also decreased the levels of vascular endothelial growth factor (VEGF121; P < 0.01) and S1P lyase (SPL; P < 0.05) and increased the levels of S1PR1 (P < 0.05) in endothelial cells. In CAMs incubated with FF from patients at risk of OHSS with S1P, the number of vessel branch points decreased while the periendothelial cell coverage increased. Additionally, in a rat OHSS model, we demonstrated that vascular permeability and VEGF121 and its receptor KDR expression were increased in the OHSS group compared to the control group and that S1P administration decreased these parameters. N/A. The results of this study were generated from an in-vitro system. This model reflects the microvasculature in vivo. Even though the ideal model would be the use of human endothelial cells from the ovary, it is obviously not possible to carry out this kind of approach in ovaries of patients from ART. More studies will be necessary to delineate the effects of S1P in the pathogenesis of OHSS. Hence, clinical studies are needed in order to choose the most appropriate method of prevention and management. The use of bioactive sphingolipid metabolites may contribute to finding better and safer therapeutic strategies for the treatment of OHSS and other human diseases that display aberrant vascular leakage. This work was supported by grants ANPCyT (PICT 2012-897), CONICET (PIP 5471), Roemmers and Baron Foundation, Argentina. The authors declare no conflict of interest.

The estrogenicity of methylparaben and ethylparaben at doses close to the acceptable daily intake in immature Sprague-Dawley rats.

The estrogenicity of parabens at human exposure levels has become a focus of concern due to the debate over whether the estrogenicity of parabens is strong enough to play a role in the increased incidence of breast cancer. In this study, the uterotrophic activities of methylparaben (MP) and ethylparaben (EP) at doses close to the acceptable daily intake as allocated by JECFA were demonstrated in immature Sprague-Dawley rats by intragastric administration, and up-regulations of estrogen-responsive biomarker genes were found in uteri of the rats by quantitative real-time RT–PCR (Q-RT-PCR). At the same time, the urinary concentrations of MP and EP, as measured by gas chromatography–mass spectrometry (GC-MS) in rats that received the same doses of MP and EP, were found to be near the high urinary levels reported in human populations in recent years. These results show the in vivo estrogenicity of MP and EP at human exposure levels, and indicate that populations exposed to large amounts of MP and EP may have a high burden of estrogenicity-related diseases. In addition, a molecular docking simulation showed interaction between the parabens and the agonist-binding pocket of human estrogen receptor α (hERα).

Expression of PPAR-γ in adipose tissue of rats with polycystic ovary syndrome induced by DHEA

The objective of this study was to investigate the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) in adipose tissue of the rat model of polycystic ovary syndrome (PCOS), induced by dehydroepiandrosterone (DHEA). Sixteen sexually immature Sprague-Dawley female rats were randomly assigned to the DHEA (n=8) or control (n=8) group. Adipose tissue was collected from the two rat groups following subcutaneous injection of DHEA in the DHEA group and a standard laboratory diet in the control group for 20 consecutive days. Reverse transcription polymerase chain reaction and western blot analysis were performed to detect expression of PPAR-γ at the mRNA and protein level in the adipose tissue. Both PPAR-γ mRNA and protein levels were decreased in the adipose tissue of DHEA‑induced PCOS rats compared to the control group. This decrease was significant (P<0.01). These results suggest that the pathogenesis of PCOS, which shares a number of common features with hyperandrogenemia, may involve the lipid metabolism pathway through inhibition of PPAR-γ.

Metabolic Effects of Angulation, Compression, and Reduced Mobility on Annulus Fibrosis in a Model of Altered Mechanical Environment in Scoliosis

Study DesignComparison of disc tissue from rat tails in 6 groups with different mechanical conditions imposed. ObjectivesTo identify disc annulus changes associated with the supposed altered biomechanical environment in a spine with scoliosis deformity using an immature rat model that produces disc narrowing and wedging. BackgroundIntervertebral discs become wedged and narrowed in a scoliosis curve, probably partly because of an altered biomechanical environment. MethodsWe subjected tail discs of 5-week-old immature Sprague-Dawley rats to an altered mechanical environment using an external apparatus applying permutations of loading and deformity for 5 weeks. Together with a sham and a control group, we studied 4 groups of rats: A) 15° angulation, B) angulation with 0.1 MPa compression, C) 0.1 MPa compression, and R) reduced mobility. We measured disc height changes and matrix composition (water, deoxyribonucleic acid, glycosaminoglycan, and hyaluronic acid content) after 5 weeks, and proline and sulphate incorporation and messenger ribonucleic acid expression at 5 days and 5 weeks. ResultsAfter 5 weeks, disc space was significantly narrowed relative to internal controls in all 4 intervention groups. Water content and cellularity (deoxyribonucleic acid content) were not different at interventional levels relative to internal controls and not different between the concave and convex sides of the angulated discs. There was increased glycosaminoglycan content in compressed tissue (in Groups B and C), as expected, and compression resulted in a decrease in hyaluronic acid size. We observed slightly increased incorporation of tritiated proline into the concave side of angulated discs and compressed discs. Asymmetries of gene expression in Groups A and B and some group-wise differences did not identify consistent patterns associating the discs' responses to mechanical alterations. ConclusionsIntervertebral discs in this model underwent substantial narrowing after 5 weeks, with minimal alteration in tissue composition and minimal evidence of metabolic changes.

The estrogenic effects of benzylparaben at low doses based on uterotrophic assay in immature SD rats

Benzylparaben (BzP), a type of parabens being used as a preservative agent in cosmetics, food, and pharmaceutical products, may be ingested by humans. In this study, we performed an immature uterotrophic assay using Sprague Dawley (SD) rats by intragastric administration to determine the estrogenic effects of BzP and found significant increases in uterine weight with doses of 0.16mg/kg body weight and higher (P<0.05). The in vivo estrogenicity of BzP was supported by in vitro results from the human estrogen receptor α (hERα)-coactivator recruiting assay and in silico molecular docking analysis performed in this study. The in vitro estrogenic activity of BzP can be observed at concentrations of 1.0×10−8 M and higher. Molecular docking analysis showed that BzP fits well into the agonist pocket of hERα. The lowest observed effect dose (LOED) (0.16mg/kg/day) of BzP is much lower than the documented LOEDs of other parabens. Actual risk may exist for people who consume a diet high in BzP or use BzP-laden cosmetics. In addition, we tested the sensitivity of Wistar rats to 17β-estradiol by immature uterotrophic assay, and no obvious uterotrophic response was observed in the rats given doses up to 100μg/kg body weight.

Effects of resveratrol on growth and function of rat ovarian granulosa cells

To evaluate the effects of resveratrol on growth and function of granulosa cells. Previously, we demonstrated that resveratrol exerts profound proapoptotic effects on theca-interstitial cells. Invitro study. Research laboratory. Immature Sprague-Dawley female rats. Granulosa cells were cultured in the absence or presence of resveratrol. DNA synthesis was determined by thymidine incorporation assay, apoptosis by activity of caspases 3/7, cell morphology by immunocytochemistry, steroidogenesis by mass spectrometry, antimüllerian hormone (AMH), and vascular endothelial growth factor (VEGF) expression by polymerase chain reaction and Western blot. Resveratrol induced a biphasic effect on DNA synthesis, whereby a lower concentration stimulated thymidine incorporation and higher concentrations inhibited it. Additionally, resveratrol slightly increased the cell number and modestly decreased the activity of caspases 3/7 with no effect on cell morphology or progesterone production. However, resveratrol decreased aromatization and VEGF expression, whereas AMH expression remained unaltered. Resveratrol, by exerting cytostatic but not cytotoxic effects, together with antiangiogenic actions mediated by decreased VEGF in granulosa cells, may alter the ratio of theca-to-granulosa cells and decrease vascular permeability, and therefore may be of potential therapeutic use in conditions associated with highly vascularized theca-interstitial hyperplasia and abnormal angiogenesis, such as those seen in women with polycystic ovary syndrome.

Viability and function of the cryopreserved whole rat ovary: comparison between slow-freezing and vitrification

To investigate four different protocols for cryopreservation of the whole rat ovary with intact vasculature to evaluate whether differences exist in post-thawing viability of the ovary after either vitrification or slow freezing. Experimental study. Obstetrics and gynecology department. Immature Sprague-Dawley female rats. Ovaries were isolated with the vascular tree intact up to the bifurcation of the abdominal aorta and were subsequently cannulated. The ovaries were flushed with increasing concentrations of the cryoprotectant dimethyl sulfoxide (DMSO) to either 1.5 or 7 M. The ovaries underwent cryopreservation by vitrification or passive slow freezing. After thawing, the ovaries were subjected to neutral red viability staining to assess the density of viable small follicles and for long-term (48 hours) incubation evaluation of steroid secretion, histology, and apoptosis assay. The follicular viability was decreased in both vitrification groups and in the slow-freezing group with the high concentration of DMSO, as compared with fresh controls. Estradiol levels in the incubation medium followed the same pattern. Light microscopy revealed well-preserved morphology in all groups after 48 hours' incubation. Apoptosis was increased in both vitrified and cryopreserved ovaries. We have developed a new method that can be used in basic studies to improve cryopreservation protocols. Our initial findings suggest that a moderate concentration of the cryoprotectant DMSO is superior to a high DMSO concentration for both vitrification and slow freezing.

Resveratrol inhibits the mevalonate pathway and potentiates the antiproliferative effects of simvastatin in rat theca-interstitial cells

To examine the mechanisms of action of resveratrol and its interaction with simvastatin on growth and the mevalonate pathway in rat theca-interstitial cells. Invitro study. Research laboratory. Immature Sprague-Dawley female rats. Theca-interstitial cells were cultured in the absence or presence of resveratrol, simvastatin, mevalonic acid, farnesyl pyrophosphate, and/or geranylgeranyl pyrophosphate. DNA synthesis was assessed by thymidine incorporation assay; 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) expression and activity were evaluated with the use of quantitative real-time polymerase chain reaction, Western blot analysis, and HMGCR activity assay. Cholesterol synthesis was determined by the conversion of [(14)C]-acetate to [(14)C]-cholesterol. Resveratrol potentiated the simvastatin-induced inhibition on cell proliferation in a concentration-dependent manner. Inhibitory effects of resveratrol were partly abrogated by the addition of mevalonic acid, farnesyl pyrophosphate, and geranylgeranyl pyrophosphate. Resveratrol reduced HMGCR expression and activity, and decreased cholesterol synthesis. In contrast, simvastatin inhibited HMGCR activity with a compensatory increase in HMGCR expression. Resveratrol counteracted this effect of simvastatin on HMGCR expression but augmented the simvastatin-induced inhibition on HMGCR activity and cholesterol synthesis. Resveratrol inhibits the mevalonate pathway via distinctly different mechanisms than statins. These observations demonstrate a novel mechanism of action of resveratrol and underscore the potential translational/clinical relevance of resveratrol interactions with simvastatin.

The expression of endothelial nitric oxide synthase and vascular endothelial growth factor to the damage of contralateral testis of unilateral cryptorchidism in rats

Objective To study the relationship between the expression of endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) with the damage of contralateral testis of unilateral cryptorchidism in the experimental rats. Methods Forty-five immature male Sprague-Dawley rats (aged 22 days) were randomly divided into the group A (unilateral cryptorchidism and the ipsilateral genitofemoral nerve division), group B (unilateral cryptorchidism), group C (sham operation), n = 15 in each group. When the rats were aged 65 days, all the rats were sacrificed and the testes were obtained. The morphological changes of the spermatogenic epithelium in the testes were observed, and the germ cell apoptosis was detected by the TdT-mediated dUTP-biotin nick end labeling (TUNEL) technique. The expression of eNOS and VEGF was detected by using Western blotting and immunohistochemistry in the testicular tissues.Results The germ cell apoptosis was increased significantly ( t1 = 3. 04, t2 = 3. 94, t1 ,t2 ＞ t28 , P ＜0. 01) , and the levels of eNOS and VEGF in the contralateral testes were also increased obviously in group B as compared with groups A and C ( P ＜ 0. 01) , but the entire indexes in groups A and C had no significant difference. Conclusion eNOS, VEGF and genitofemoral nerve play a important role in the damage of the contralateral testes of unilateral cryptorchidism, and the damage can be prevented by genitofemoral nerve division. Key words: Cryptorchidism; Genitofemoral never; Vascular endothelial growth factor; Endothelial nitric oxide synthase

Daily treatment with α-naphthoflavone enhances follicular growth and ovulation rate in the rat

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and the first protein involved in a variety of physiological and toxicological processes, including those of xenobiotic metabolizing enzymes. AhR has been found in the ovary of many species and seems to mediate the ovarian toxicity of many environmental contaminants, which are AhR ligands. However, the role of AhR in the ovarian function is unknown. Therefore, the aim of this work was to study the action of α-naphthoflavone (αNF), known to be an AhR antagonist, on both follicular growth and ovulation. Immature Sprague–Dawley rats were daily injected intraperitoneally with αNF (0.1–80mg/kg) or vehicle for 12days, and primed with gonadotrophins (eCG/hCG) to induce follicular growth and ovulation. Ovaries were obtained 20h after hCG administration. By means of immunohistochemistry, we found that the numbers of primordial, primary and antral follicles were increased in rats treated with 80mg/kg αNF and that there were no differences with other doses. Likewise, the ovarian weight and the ovulation rate, measured by both number of oocytes within oviducts and corpora lutea in ovarian sections, were increased when the rats received either 1 or 10mg/kg daily. Although further studies are necessary to know the mechanism of action of αNF, it is possible that the different ovarian processes can be differentially responsive to the presence of different levels of αNF, and that the same or different endogenous AhR ligands can be involved in these ovarian processes in a cell type-dependent manner.

Tamoxifen-elicited uterotrophy: cross-species and cross-ligand analysis of the gene expression program

BackgroundTamoxifen (TAM) is a well characterized breast cancer drug and selective estrogen receptor modulator (SERM) which also has been associated with a small increase in risk for uterine cancers. TAM's partial agonist activation of estrogen receptor has been characterized for specific gene promoters but not at the genomic level in vivo.Furthermore, reducing uncertainties associated with cross-species extrapolations of pharmaco- and toxicogenomic data remains a formidable challenge.ResultsA comparative ligand and species analysis approach was conducted to systematically assess the physiological, morphological and uterine gene expression alterations elicited across time by TAM and ethynylestradiol (EE) in immature ovariectomized Sprague-Dawley rats and C57BL/6 mice. Differential gene expression was evaluated using custom cDNA microarrays, and the data was compared to identify conserved and divergent responses. 902 genes were differentially regulated in all four studies, 398 of which exhibit identical temporal expression patterns.ConclusionComparative analysis of EE and TAM differentially expressed gene lists suggest TAM regulates no unique uterine genes that are conserved in the rat and mouse. This demonstrates that the partial agonist activities of TAM extend to molecular targets in regulating only a subset of EE-responsive genes. Ligand-conserved, species-divergent expression of carbonic anhydrase 2 was observed in the microarray data and confirmed by real time PCR. The identification of comparable temporal phenotypic responses linked to related gene expression profiles demonstrates that systematic comparative genomic assessments can elucidate important conserved and divergent mechanisms in rodent estrogen signalling during uterine proliferation.