The reliability and validity of the training elements scale for clinicians in the new era--based on the perspective of Chinese doctors' job demands.

OBJECTIVE: The purpose of this study was to develop a scale of clinician training elements in the new period and test its reliability and validity. METHODS: Our approach was based on interdisciplinary theory, systematology, collaborative innovation theory, and whole person education theory combined with the existing post competency model of Chinese doctors and the responsibilities and requirements endowed clinicians in the new historical period. The scale elements were extracted by referring to the relevant literature, and the training elements scale for clinicians in the new period were preliminarily formed. From July to August 2022, 1,086 clinicians from tertiary medical institutions in eastern, central, and western China were sampled and investigated. The questionnaire was revised via the critical ratio method and homogeneity test method, and the reliability and validity of the scale were also tested. RESULTS: The training elements scale for clinicians in the new period included the following eight dimensions: basic clinical knowledge, interdisciplinary knowledge, clinical skill operation, public health knowledge, technological innovation capability, lifelong learning needs, medical humanistic literacy, and international exchange vision, as well as 51 other items. The Cronbach's α coefficient of the scale was 0.981, the half-reliability was 0.903, and the average variance extraction of each dimension was greater than 0.5. An exploratory factor analysis extracted eight main factors, and the cumulative variance contribution rate was 78.524%. Confirmatory factor analysis showed that the model fit was ideal and the factor structure was stable. CONCLUSION: The clinician training factor scale in the new era can fully meet the current training needs of r clinicians, and has good reliability and validity. It can be widely used in medical colleges and universities as a reference to reform the content of medical training and education, and can also be used in the continuing education of clinicians after graduation to compensate for gaps in knowledge during clinical work.

Hyperlactatemia in patients undergoing pulmonary endarterectomy with deep hypothermic circulatory arrest: Risk factors and its effects on the outcome.

INTRODUCTION: To determine the risk factors of hyperlactatemia in pulmonary endarterectomy (PEA) surgery and assess whether elevated blood lactate levels are associated with adverse outcomes. METHODS: In this retrospective observational study, a total of 111 consecutive patients who underwent PEA for chronic thromboembolic pulmonary hypertension at the XXX Hospital between December 2016 and January 2022 were included. We retrospectively evaluated arterial blood samples analyzed intraoperatively. The pre- and intraoperative risk factors for hyperlactatemia and the postoperative outcomes were recorded. RESULTS: Lactate levels gradually increased during surgery. The optimal cut-off lactate level for major postoperative complications, calculated using receiver operating characteristic analysis, was 7.0 mmol/L. Deep hypothermic circulatory arrest (DHCA) duration, nadir hematocrit, and preoperative pulmonary vascular resistance were risk factors for lactate levels >7 mmol/L. Moreover, the intraoperative peak lactate level during PEA under DHCA was found to be a statistically significant predictor of major complications being associated with longer mechanical ventilation time (r = 0.294; p = .003) and intensive care unit length of stay (r = 0.327; p = .001). CONCLUSIONS: Deep hypothermic circulatory arrest duration, nadir hematocrit, and preoperative pulmonary vascular resistance were associated with hyperlactatemia. Increased lactate levels were independent predictors of longer mechanical ventilation time, intensive care unit length of stay, and major complications.

[Analysis of a Chinese pedigree affected with Spinal muscular atrophy due to compound heterozygous variants of SMN gene].

OBJECTIVE: To analyze variants of SMN gene in a Chinese pedigree affected with Spinal muscular atrophy (SMA). METHODS: A Chinese pedigree diagnosed at the Nanchang First Hospital in January 2020 was selected as the study subject. Peripheral blood samples were collected for the extraction of DNA. All exons of the SMN gene were detected by multiple ligation-dependent probe amplification (MLPA). Potential variants of the SMN gene were also detected by Whole exome sequencing (WES), and the result was verified by Sanger sequencing. cDNA extracted from fresh blood sample was used as a template to verify the location of variant on the SMN genes. RESULTS: The proband was found to harbor a heterozygous deletion of the SMN1 Exon7+Exon8, and a heterozygous c.81G>A variant. The SMN1 Exon7+Exon8 deletion was inherited from her father and grandmother, whilst the c.81G>A variant was inherited from her mother and maternal grandfather. Her aunt was also a carrier of the heterozygous deletion, while her paternal aunt, her husband, and their daughter were not. cDNA amplification and Sanger sequencing confirmed that the c.81G>A variant was located in the SMN1 gene. CONCLUSION: MLPA combined with NGS and Sanger sequencing can identify compound heterozygous variants of the SMN gene in the SMA patients.

Duration of regional cerebral oxygen saturation under 40% is a risk factor for neurological injury following pulmonary thromboendarterectomy: A prospective observational study.

BACKGROUND: Deep hypothermic circulatory arrest (DHCA) is nowadays commonly used in pulmonary thromboendarterectomy (PTE). Neurological injury related to DHCA severely impairs the prognosis of patients. However, the risk factors and predictors of neurological injury are still unclear. METHODS: We conducted a prospective observational study, including 82 patients diagnosed as chronic thromboembolic pulmonary hypertension and underwent PTE alone in our center from December 2016 to May 2021. Demographic characteristics, clinical and surgical data, and neurological adverse events were recorded prospectively. Univariate and multivariate analyses were conducted to identify the predictors of neurological injury. RESULTS: Eleven (13.4%) patients exhibited neurological injuries after surgery. Univariate analysis showed that the duration of regional cerebral oxygen saturation (rSO2 ) under 40% (p < .001), the minimum rSO2 (p = .006), and the percentage of decrease in rSO2 (p = .011) were significantly associated with neurological injury. Multivariate analysis showed that the duration of rSO2 under 40% was an independent predictor for postoperative neurological injury (odds ratio = 3.896, 95% confidence interval: 1.812-8.377, p < .001). The receiver operating characteristic curve showed that when the cut-off value was 1.25 min, its sensitivity for predicting neurological injury was 63.6% with a specificity of 88.7%. CONCLUSIONS: The duration of rSO2 under 40% is an independent predictor for neurological injury following PTE. For complicated lesions, more times of circulatory arrest were much safer and more reliable than a prolonged time of a single circulatory arrest. The circulation should be restored as soon as possible, when the rSO2 under 40% is detected, rather than waiting for 5 min.

Gestational vinclozolin exposure suppresses fetal testis development in rats.

Vinclozolin is a common dicarboximide fungicide used to protect crops from diseases. It is also an endocrine disruptor and is thought to be related to abnormalities of the reproductive tract. However, its mechanism of inducing abnormalities of the male reproductive tract is still unclear. The purpose of this study was to study the effect of gestational vinclozolin exposure on the development of rat fetal Leydig cells. Female pregnant Sprague-Dawley rats were exposed to vinclozolin (0, 25, 50, and 100 mg/kg body weight/day) by gavage from gestational day 14-21. Vinclozolin dose-dependently reduced serum testosterone levels at doses of 50 and 100 mg/kg and the anogenital distance at 100 mg/kg. RNA-seq, qPCR, and Western blotting showed that vinclozolin down-regulated the expression of Nr5a1, Sox9, Lhcgr, Cyp11a1, Hsd3b1, Hsd17b3, Amh, Pdgfa, and Dhh and their encoded proteins. Vinclozolin reduced the number of NR2F2-positive stem Leydig cells at a dose of 100 mg/kg and enhanced autophagy in the testes. In conclusion, vinclozolin disrupts reproductive tract development and testis development in male fetal rats via several pathways.

The dynamic observation of plasma concentration of antimicrobial agents during balanced ultrafiltration in vitro.

Routine perioperative intravenous antimicrobial agents are administered as surgical prophylaxis. However, whether balanced ultrafiltration during extracorporeal circulation has substantial effect on the concentration of antimicrobial agents remains unclear. The concentrations of antimicrobial agents in plasma and ultrafiltrate samples were measured in this pseudo-extracorporeal circulation model. Extracorporeal circulation consisted of cardiotomy reservoir, membrane oxygenator, and pediatric arterial line filter. A hemoconcentrator was placed between the arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. Two kinds of antimicrobial agents, cefotiam (320 mg) and cefmetazole (160 mg), were bolus added into the circuit. After 30 min of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100 mm Hg with a Hoffman clamp. The rate of ultrafiltration (12 mL/min) was controlled by ultrafiltrate outlet pressure. An identical volume of Plasmalyte A was dripped into the circuit to maintain stable hematocrit during 45 min of experiment. Plasma and ultrafiltrate samples were drawn every 5 min, and concentrations of antimicrobial agents (including cefotiam and cefmetazole) were measured with high performance liquid chromatography. Both antimicrobial agents were detected in ultrafiltrate, demonstrating hemoconcentration may remove antimicrobial agents. The concentrations of plasma antimicrobial agents decreased linearly with the increase of ultrafiltrate volume. At end of balanced ultrafiltration, the concentration of plasma cefotiam was 104.96 ± 44.36 mg/L, which is about 44.38% ± 7.42% of the initial concentration (238.95 ± 101.12 mg/L) (P < 0.001); the concentration of plasma cefmetazole decreased linearly to 25.76 ± 14.78 mg/L, which is about 49.69% ± 10.49% of the initial concentration (51.49 ± 28.03 mg/L) (P < 0.001). The total amount of cefotiam in ultrafiltrate is 27.16% ± 12.17% of the total dose administered, whereas cefmetazole in ultrafiltrate is 7.74% ± 4.17%. Balanced ultrafiltration may remove antimicrobial agents from plasma and has a prominent influence on plasma concentration of antimicrobial agent. The strategy of surgical prophylaxis should consider this unique technique during extracorporeal circulation.

Bone morphogenetic protein 4 inhibits rat stem/progenitor Leydig cell development and regeneration via SMAD-dependent and SMAD-independent signaling.

Bone morphogenetic protein 4 (BMP4) is an important member of the transforming growth factor-ß superfamily. BMP4 is expressed in the Leydig cell lineage. We hypothesized that BMP4 might regulate the development of stem/progenitor Leydig cells. The BMP4 receptors, BMPR1A, BMPR1B, and BMPR2 were found to be expressed in progenitor Leydig cells of prepubertal testis and isolated cells. BMP4 at 1 and 10 ng/mL significantly reduced androgen production and down-regulated steroidogenesis-related gene and protein expression possibly by activating the SMAD signaling pathway (increasing SMAD1/5 phosphorylation and SMAD4) at 24 h treatment. BMP4 at 0.1 ng/mL and higher concentrations markedly reduced the EdU labeling index of CD90+ stem Leydig cells after 24 h treatment and significantly reduced the number of EdU+ stem Leydig cells on the surface of seminiferous tubules after 7 days of culture. BMP4 at 0.01 ng/mL and higher concentrations significantly blocked the differentiation of stem Leydig cells into adult cells, as shown by the reduction of testosterone secretion and the downregulation of Lhcgr, Scarb1, Cyp11a1, Hsd11b1, and Insl3 and their function after 3D seminiferous tubule culture for 3 weeks, and this effect was reversed by co-treatment with the BMP4 antagonists noggin and doxomorphine. In addition, BMP4 also blocked stem Leydig cell differentiation through SMAD-independent signaling pathways (ERK1/2 and AMPK). Ethanedimethane sulfonate (EDS) single injection can result in reduction of testosterone, restoration can happen post treatment. In an in vivo model of Leydig cell regeneration following EDS treatment, intratesticular injection of BMP4 from day 14 to day 28 post-elimination significantly reduced serum testosterone levels and down-regulated the expression of Scarb1, Star, Hsd11b1, and Insl3 and its proteins, possibly through SMAD-dependent and SMAD-independent (ERK1/2 and AMPK) signaling pathways. In conclusion, BMP4 is expressed in cells of the Leydig cell lineage and blocks entry of stem/progenitor Leydig cells into adult Leydig cells through SMAD-dependent and SMAD-independent signaling pathways.

Targeted knockdown of EGR-1 inhibits IL-8 production and IL-8-mediated invasion of prostate cancer cells through suppressing EGR-1/NF-kappaB synergy.

IL-8 produced by prostate cancer cells may be responsible for the androgen-independent growth of advanced prostate cancers. Accumulating evidence from microarray analyses and animal genetic models highlights the central involvement of the transcription factor early growth response-1 (EGR-1) in prostate carcinoma progression. It is unknown, however, whether knockdown of EGR-1 inhibits IL-8 production and IL-8-mediated tumor metastasis. Here we show that EGR-1 knockdown by a specific shRNA-Egr1 inhibited gene transcription and production of IL-8 by the human prostate cancer cell line DU145. Conversely, enforced expression of EGR-1 in EGR-1-lacking PC3 prostate cancer cells markedly enhanced IL-8 transcription and secretion. By using wild type and a series of mutant IL-8 promoter luciferase constructs, we found that the NF-kappaB binding site is important for EGR-1 regulation of IL-8. Furthermore, silencing EGR-1 suppressed a synergistically functional interaction between EGR-1 and NF-kappaB. Consequently, knockdown of EGR-1 inhibited IL-8-mediated tumor colony formation and invasion. Thus, targeted knockdown of EGR-1 could be an effective therapeutic approach against prostate cancer.

Taxifolin attenuates the developmental testicular toxicity induced by di-n-butyl phthalate in fetal male rats.

Di-n-butyl phthalate (DBP) is widely used in consumer products as a plasticizer. Here, we report a natural product taxifolin that can attenuate developmental and reproductive toxicity of DBP. Pregnant rats were daily gavaged with 500 mg/kg DBP alone or together with taxifolin (10 and 20 mg/kg) from gestational day (GD) 12-21. At GD21, sera and testes of male fetus were collected. DBP significantly lowered serum testosterone level at 500 mg/kg and taxifolin can completely reverse its action. DBP caused abnormal aggregation of fetal Leydig cells and taxifolin can reverse it. DBP down-regulated the expression of the genes of cholesterol side-chain cleavage enzyme (Cyp11a1), 17ß-hydroxysteroid dehydrogenase 3 (Hsd17b3), and insulin-like 3 (Insl3) and taxifolin can reverse its action. DBP increased malondialdehyde levels and decreased superoxide dismutase and glutathione peroxidase expression and taxifolin can reverse it. DBP increased incidence of multinucleated gonocytes and taxifolin can prevent it. Moreover, DBP lowered sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and phosphorylated AMP-activated protein kinase (pAMPK) signalling and taxifolin antagonized DBP. In conclusion, in utero exposure to DBP caused developmental/reproductive toxicity of male offspring via increasing reactive oxygen species and taxifolin is an effective food component that completely reverses DBP-mediated action.

Zearalenone disrupts the placental function of rats: A possible mechanism causing intrauterine growth restriction.

Zearalenone is an estrogenic mycotoxin produced by a variety of Fusarium fungi. There is evidence that exposure to zearalenone can cause intrauterine growth restriction, but little is known about the mechanism in the rat placenta caused by zearalenone. From gestational day 14-21, female Sprague Dawley rats (60 days old) were gavaged with zearalenone (0, 2.5, 5, 10, and 20 mg/kg/day body weight). Zearalenone dose-dependently reduced serum LH and FSH levels of dams at ≥ 5 mg/kg. RNA-seq and qPCR showed that zearalenone significantly down-regulated Slc38a1 expression at 2.5 mg/kg, Echs1 and Pc at 10 mg/kg, as well as Slc1a5, Cd36, Ldlr, Hadhb, and Cyp17a1 expression at a dose of 20 mg/kg, while it up-regulated the expression of Notch signal (Dvl1 and Jag 1). After zearalenone treatment, their proteins showed a similar trend. Zearalenone reduced the phosphorylation of AKT1, ERK1/2, and mTOR at 5 mg/kg or higher and 4EBP1 at 5 mg/kg. Zearalenone also increased BECLIN1, LC3B, and p62 levels and elevated BAX/BCL2 and CASP3/PROCASP3 ratios. In conclusion, zearalenone disrupts placental function such as reduction of nutrient transport and lipid metabolism possibly via AKT1/ERK1/2/mTOR-mediated autophagy and apoptosis.

Aconitine inhibits androgen synthesis enzymes by rat immature Leydig cells via down-regulating androgen synthetic enzyme expression in vitro.

Aconitine might have reproductive toxicity and the effects of aconitine on androgen synthesis in Leydig cells remain unclear. Here, we explore how aconitine affects androgen synthesis and metabolism in rat immature Leydig cells in vitro. Immature Leydig cells were isolated from 35-day-old male Sprague Dawley rats and cultured with 0-50 µM aconitine for 3 h in combination with LH, 8Br-cAMP, 22R-hydroxycholesterol, pregnenolone, progesterone, androstenedione, testosterone, and dihydrotestosterone, respectively. Medium androgens were measured. The levels of Leydig cell mRNAs, Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Srd5a1, and Akr1c14, were measured by qPCR. ROS and apoptosis were determined after 24-h aconitine treatment. Aconitine inhibited basal androgen production in Leydig cells at 0.05 µM and the higher concentrations. Aconitine blocked pregnenolone, progesterone, and androstenedione mediated androgen outputs without affecting 22R-hydroxycholesterol-mediated androgen production at 5 µM. Aconitine also inhibited LH and 8Br-cAMP stimulated androgen outputs at 5 µM. Further investigation showed that aconitine blocked androgen synthesis via down-regulating the expression of Scarb1, Hsd3b1, Cyp17a1, and Hsd17b3. At 50 µM, aconitine also induced ROS generation and increased apoptotic rate of Leydig cells. Aconitine lowered serum testosterone levels at 1.5 mg/kg after 7 days of oral exposure from postnatal day 35. In conclusion, aconitine inhibits androgen synthesis.

Stem Leydig cell regeneration in the adult rat testis is inhibited after a short-term triphenyltin exposure.

Triphenyltin (TPT) is an organotin compound and may be an endocrine disruptor, impairing the male reproductive system. However, the effect of short-term TPT exposure on stem Leydig cell regeneration later on remains unknown. Here, we show that TPT affects stem Leydig cell regeneration in the adult rat testis. Adult male Sprague Dawley rats were gavaged with TPT (0, 0.5, 1.0, 2.0 mg/kg body weight/day) for 10 days, followed by a single intraperitoneal injection of ethane dimethane sulfonate (EDS, 75 mg/kg body weight) to eliminate Leydig cells. Testis parameters and hormone levels were investigated on post-EDS days 21, 35, and 56. TPT significantly reduced serum testosterone levels, decreased Leydig cell number and cell size, and down-regulated its specific gene and protein expression at 1.0 and 2.0 mg/kg even 56 days after cession of treatment. TPT lowered PCNA-labeling index of progenitor Leydig cells on post-EDS day 21. TPT also lowered AKT1 and AKT2, and ERK1/2 phosphorylation on post-EDS day 56. This study reveals that a short-term exposure to TPT blocks stem Leydig cell regeneration in the long term thus delaying spermatogenesis.

Diethylstilbestrol inhibits human and rat 11ß-hydroxysteroid dehydrogenase 2.

Glucocorticoid hormone might cause intrauterine growth restriction. The glucocorticoid-metabolizing enzyme 11ß-hydroxysteroid dehydrogenase 2 (HSD11B2) in the placenta eliminates excess levels of glucocorticoids during pregnancy. The aim of the current study was to define the effects of diethylstilbestrol (DES) on HSD11B2 activity in the mammalian placentas and identify its mode of action. Rat and human placental microsomal HSD11B2 were incubated with different concentrations of DES, and IC50 values were determined. The mode of action was analyzed by incubation of DES together with substrates, glucocorticoid and NAD+. DES suppressed rat and human HSD11B2 with IC50 values of 5.33 and 12.62 µM, respectively. DES was a competitive inhibitor of rat and human HSD11B2 when steroid substrates were added, while it was an uncompetitive inhibitor when cofactor NAD+ was exposed. Oral administration of DES (0.5 mg/kg) to the rat delayed the cortisol metabolism in adult female Sprague-Dawley rats, as indicated by the increases in cortisol's elimination half-life, maximum concentration and area under the curve. In conclusion, DES is a potent HSD11B2 inhibitor, possibly contributing to the intrauterine growth restriction.

Dicyclohexyl phthalate blocks Leydig cell regeneration in adult rat testis.

Dicyclohexyl phthalate (DCHP) is a phthalate plasticizer with a ring structure in the alcohol moiety. The objective to the current study was to determine the effects of DCHP on Leydig cell regeneration in the adult rat-testis. Adult male Sprague Dawley rats received intraperitoneally an injection of ethane dimethane sulfone (EDS) to eliminate all Leydig cells in the testis and then were divided into 4 groups of 0 (control), 10, 100, and 1000 mg/kg/day DCHP. Rats were gavaged either vehicle (corn oil, control) or DCHP from post-EDS day 7 to day 21 and 28. On post-EDS day 21 and day 28, rats were euthanized and serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) levels were measured, and Leydig cell number, cell size, gene, and protein expression were evaluated. During the course of exposure, DCHP did not cause the general toxicity to rats. On post-EDS day 21, DCHP significantly increased serum testosterone level at 10 and 100 mg/kg and increased Leydig cell number at 10 mg/kg via stimulating their mitosis. On post-EDS day 28, DCHP lowered serum testosterone levels and Leydig cell number at 1000 mg/kg. DCHP dose-dependently down-regulated the expression of many Leydig cell genes (Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Hsd11b1, and Insl3) and their proteins, especially at 1000 mg/kg. DCHP also lowered the pAKT1/AKT1 and pERK1/2/ERK1/2 ratios. In conclusion, DCHP at low doses (10 and 100 mg/kg) increased Leydig cell number during the initial regeneration and inhibited Leydig cell regeneration during the course of its exposure.

In utero exposure to bisphenol A disrupts fetal testis development in rats.

Bisphenol A (BPA) is widely used in consumer products and is a potential endocrine disruptor linked with abnormal development of male reproductive tract. However, its action and its effects on the pathways in the development of male gonad are still unclear. Here we report that effects of BPA exposure during gestation on male gonad development. Sprague-Dawley rats were gavaged daily with BPA (0, 4, 40, and 400 mg/kg body weight) from gestational day 12 to day 21. BPA dose-dependently decreased serum testosterone levels (0.45 ±â€¯0.08 ng/ml and 0.32 ±â€¯0.08 ng/ml for 40 and 400 mg/kg BPA, respectively) versus the control level (1.11 ±â€¯0.22 ng/ml, Mean ±â€¯SE). BPA lowered Leydig cell Insl3 and Hsd17b3 mRNA and their protein levels at doses of 40 and 400 mg/kg. BPA also lowered Leydig cell (Lhcgr, Cyp11a1, and Cyp17a1) and Sertoli cell (Amh) mRNA and their protein levels at 400 mg/kg. BPA decreased fetal Leydig cell number via inhibiting their proliferation, but it did not affect fetal Sertoli cell number. In conclusion, the current study shows that in utero exposure to BPA inhibits fetal Leydig and Sertoli cell differentiation, possibly disrupting the development of male reproductive tract.

Effects of dexmedetomidine on the steroidogenesis of rat immature Leydig cells.

Dexmedetomidine (DEX), an imidazole compound, is an anesthetic drug used perioperatively. In the current study, we investigated the effects of DEX on androgen production in rat immature Leydig cells in vitro. Leydig cells isolated from pubertal Sprague Dawley rats were treated with various concentrations of DEX (0.015-1.5 µM) for 3 h and medium 5α-androstanediol and testosterone levels and the expression of Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Srd5a1 and Akr1c14 in Leydig cells were determined. At 0.015-1.5 µM, DEX concentration-dependently inhibited androgen secretion and downregulated Cyp17a1 and Srd5a1 mRNA levels. DEX equally blocked the LH- and cAMP-stimulated secretion of androgens. Using the steroid substrates, 22R-hydroxycholesterol (for cytochrome P450 cholesterol side chain cleavage), pregnenolone (for 3ß-hydroxysteroid dehydrogenase 1), progesterone (for cytochrome P450 17α-hydroxylase/C17,C20-lyase), androstenedione (for 17ß-hydroxysteroid dehydrogenase 3), testosterone (for steroid 5α-reductase 1), and dihydrotestosterone (for 3α-hydroxysteroid dehydrogenase), it was demonstrated that DEX inhibited 22R-hydroxycholesterol, pregnenolone, progesterone, and testosterone-mediated 5α-androstanediol formation at 1.5 µM. Further study demonstrated that DEX also directly inhibited rat testis cholesterol side chain cleavage, 3ß-hydroxysteroid dehydrogenation, and 17α-hydroxylation at 1.5 µM. DEX induced ROS production and increased apoptosis rate in immature Leydig cells after 24-h treatment at ≥0.15 µM. In conclusion, DEX directly inhibits the activities of some steroidogenic enzymes and downregulates the expression of Cyp17a1 and Srd5a1, and increases ROS production, thus leading to lower production of androgens in immature Leydig cells.

Paraquat exposure delays stem/progenitor Leydig cell regeneration in the adult rat testis.

Paraquat, a widely used nonselective herbicide, is a serious hazard to human health. However, the effects of paraquat on the male reproductive system remain unclear. In this study, adult male Sprague Dawley rats were intraperitoneally injected ethane dimethane sulfonate (EDS, 75 mg/kg) to initiate a regeneration of Leydig cells. EDS-treated rats were orally exposed to paraquat (0.5, 2, 8 mg/kg/day) from post-EDS day 17 to day 28 and effects of paraquat on Leydig and Sertoli cell functions on post-EDS day 35 and day 56 were investigated. Paraquat significantly decreased serum testosterone levels at 2 and 8 mg/kg. Paraquat lowered Leydig cell Hsd17b3, Srd5a1, and Hsd11b1 mRNA levels but increased Hsd3b1 on post-EDS day 35. Paraquat lowered Cyp11a1, Cyp17a1, and Hsd11b1 but increased Srd5a1 on post-EDS day 56. However, paraquat did not alter Leydig cell number and PCNA labeling index. Epididymal staining showed that few sperms were observed in paraquat-treated rats. Primary culture of adult Leydig cells showed that paraquat diminished testosterone output and induced reactive oxygen species generation at 1 and 10 µM and apoptosis rate at 10 µM. In conclusion, a short-term exposure to paraquat delays Leydig cell regeneration from stem/progenitor Leydig cells, causing low production of testosterone and an arrest of spermatogenesis.

In utero Exposure to Atrazine Disrupts Rat Fetal Testis Development.

Atrazine (ATR) is a commonly used agricultural herbicide and a potential endocrine disruptor that may cause testicular dysgenesis. The objective of the present study was to investigate the effects of atrazine on fetal testis development after in utero exposure. Female Sprague-Dawley rats were gavaged daily with vehicle (corn oil, control) or atrazine (25, 50, and 100 mg/kg body weight/day) from gestational day 12 to 21. Atrazine dose-dependently decreased serum testosterone levels of male pups, with a significant difference from the control recorded at a dose of 100 mg/kg. In addition, atrazine significantly increased fetal Leydig cell aggregation at a dose of 100 mg/kg. Atrazine increased fetal Leydig cell number but not Sertoli cell number. However, atrazine down-regulated Scarb1 and Cyp17a1 in the fetal Leydig cell per se and Hsd17b3 and Dhh in the Sertoli cell per se. These results demonstrated that in utero exposure to atrazine disrupted rat fetal testis development.

4-Bromodiphenyl ether delays pubertal Leydig cell development in rats.

Polybrominated diphenyl ethers are a class of brominated flame retardants that are potential endocrine disruptors. 4-Bromodiphenyl ether (BDE-3) is the most abundant photodegradation product of higher polybrominated diphenyl ethers. However, whether BDE-3 affects Leydig cell development during puberty is still unknown. The objective of this study was to explore effects of BDE-3 on the pubertal development of rat Leydig cells. Male Sprague Dawley rats (35 days of age) were gavaged daily with BDE-3 (0, 50, 100, and 200 mg/kg body weight/day) for 21 days. BDE-3 decreased serum testosterone levels (1.099 ±â€¯0.412 ng/ml at a dose of 200 mg/kg BDE-3 when compared to the control level (2.402 ±â€¯0.184 ng/ml, mean ±â€¯S.E.). BDE-3 decreased Leydig cell size and cytoplasmic size at a dose of 200 mg/kg, decreased Lhcgr, Star, Dhh, and Sox9 mRNA levels at ≥ 100 mg/kg and Scarb1, Cyp11a1, Hsd17b3, and Fshr at 200 mg/kg. BED-3 also decreased the phosphorylation of AKT1, AKT2, ERK1/2, and AMPK at 100 or 200 mg/kg. BDE-3 in vitro induced ROS generation, inhibited androgen production, down-regulated Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Srd5a1, and Akr1c14 expression in immature Leydig cells after 24-h treatment. In conclusion, the current study indicates that BDE-3 disrupts Leydig cell development via suppressing AKT, ERK1/2, and AMPK phosphorylation and inducing ROS generation.

Lambda-cyhalothrin delays pubertal Leydig cell development in rats.

Lambda-cyhalothrin (LCT) is a widely used broad-spectrum pyrethroid insecticide and is expected to cause deleterious effects on the male reproductive system. However, the effects of LCT on Leydig cell development during puberty are unclear. The current study addressed these effects. Twenty-eight-day-old male Sprague Dawley rats orally received LCT (0, 0.25, 0.5 or 1 mg/kg body weight/day) for 30 days. The levels of serum testosterone, luteinizing hormone, and follicle-stimulating hormone, Leydig cell number, and its specific gene and protein expression were determined. LCT exposure lowered serum testosterone levels at doses of 0.5 and 1 mg/kg and luteinizing hormone levels at a dose of 1 mg/kg, but increased follicle-stimulating hormone levels at doses of 0.5 and 1 mg/kg. LCT lowered Star and Hsd3b1 mRNA or their protein levels at a dose of 1 mg/kg. Immature Leydig cells were purified from pubertal rats and treated with different concentrations of LCT for 24 h and medium androgen levels, Leydig cell mRNA and protein levels, the mitochondrial membrane potential (△Ψm), and the apoptotic rate of immature Leydig cells were investigated. LCT inhibited androgen production at 5 µM and downregulated Scarb1 at 0.05 µM, Hsd3b1 and Hsd11b1 at 0.5 µM, and Cyp11a1 at 5 µM. LCT also decreased △Ψm at 0.5 and 50 µM. In conclusion, LCT can influence the function of Leydig cells.