Shengde Wu

Dynamic Effect of Di-2-(Ethylhexyl) Phthalate on Testicular Toxicity: Epigenetic Changes and Their Impact on Gene Expression

This study investigated epigenetic (specifically, DNA methylation) changes and their impact on gene expression in testes induced by maternal exposure to Di-2-(ethylhexyl) phthalate (DEHP) in mice. Testicular dysgenesis syndrome was induced in fetuses and pups by maternal exposure to DEHP at 500 mg/kg/d, and testes were excised for analysis on gestation day (GD) 19 and postnatal days (PNDs) 3, 21, 56, and 90. High-performance liquid chromatography (HPLC) was performed to analyze DNA methylation status, and expression levels of the DNA methyltransferases were examined by quantitative real-time polymerase chain reaction (qPCR). Testis-specific gene, insulin-like hormone 3 (Insl3), and testosterone production were also detected. DEHP significantly increased DNA methylation levels on GD 19 and PND 3 (P < .05 and P < .05) but not on PNDs 21, 56, and 90. DEHP also significantly increased the expression of DNA methyltransferases. For DNA methyltransferase 1, the difference was not significant on PND 21, and DNA methyltransferase 3a and 3b returned to normal levels on PND 56. Fetal testes were a main target for DEHP as evidenced by a reduction in Insl3 expression and testosterone production. Effects of DEHP on Insl3 expression continued until PND 21. The DEHP-induced suppression of testosterone had not recovered on PND 56. Changes in DNA methylation may play an important role in abnormal testicular function caused by environmental factors such as maternal exposure to DEHP, which may be a mechanism of DEHP-mediated testicular toxicity.

The Mechanism of Environmental Endocrine Disruptors (DEHP) Induces Epigenetic Transgenerational Inheritance of Cryptorchidism

Discussion on the role of DEHP in the critical period of gonadal development in pregnant rats (F0), studied the evolution of F1-F4 generation of inter-generational inheritance of cryptorchidism and the alteration of DNA methylation levels in testis. Pregnant SD rats were randomly divided into two groups: normal control group and DEHP experimental group. From pregnancy 7d to 19d, experimental group was sustained to gavage DEHP 750mg/kg bw/day, observed the incidence of cryptorchidism in offspring and examined the pregnancy rate of female rats through mating experiments. Continuous recording the rat’s weight and AGD value, after maturation (PND80) recording testis and epididymis’ size and weight, detected the sperm number and quality. Subsequently, we examined the evolution morphological changes of testicular tissue for 4 generation rats by HE staining and Western Blot. Completed the MeDIP-sequencing analysis of 6 samples (F1 generation, F4 generation and Control). DEHP successfully induced cryptorchidism occurrence in offspring during pregnancy. The incidence of cryptorchidism in F1 was 30%, in F2 was 12.5%, and there was no cryptorchidism coming up in F3 and F4. Mating experiment shows conception rate 50% in F1, F2 generation was 75%, the F3 and F4 generation were 100%. HE staining showed that the seminiferous epithelium of F1 generation was atrophy and with a few spermatogenic cell, F2 generation had improved, F3 and F4 generation were tend to be normal. The DNA methyltransferase expression was up-regulated with the increase of generations by Real Time-PCR, immunohistochemistry and Western Blot. MeDIP-seq Data Analysis Results show many differentially methylated DNA sequences between F1 and F4. DEHP damage male reproductive function in rats, affect expression of DNA methyltransferase enzyme, which in turn leads to genomic imprinting methylation pattern changes and passed on to the next generation, so that the offspring of male reproductive system critical role in the development of imprinted genes imbalances, and eventually lead to producing offspring cryptorchidism. This may be an important mechanism of reproductive system damage.

Propofol induces neuronal apoptosis in infant rat brain under hypoxic conditions.

Propofol is currently one of the most widely used intravenous anesthetic. In the present study, we investigated the effects of propofol on neuropathogenesis in newborn rats under hypoxic conditions. Seven-day old SD rats were assigned into one of the six treatments: propofol+50% oxygen (propofol-oxygen, PO), propofol+room air (propofol-air, PA), propofol+18% oxygen (propofol-hypoxia, PH), control group: lipid emulsion solvent+50% oxygen (CO), lipid emulsion solvent+room air (CA), lipid emulsion solvent+18% oxygen (CH). The rats assigned to anesthesia or control groups received intraperitoneally (ip) propofol 50 mg/kg or identical volume of lipid emulsion solvent (5.0 ml/kg) for seven days. SaO(2) (%) and respiratory rate (RR) were monitored throughout the procedures. The rats were decapitated 24h after 7 days exposure. TUNEL staining, Nissl staining, ultrastructural changes and the expression of caspase-3 in the brain tissues were assessed. We found propofol-induced attenuation of respiration could produce lower oxygen concentrations in the blood (hypoxia) under air or mild hypoxia conditions. Interestingly, in the presence of oxygen completely rescued hypoxia to normal levels, suggesting that propofol-induced respiratory depression led to hypoxia only under air or mild hypoxic conditions (propofol/hypoxia). In addition, propofol indirectly induced apoptosis through hypoxia resulting from respiratory depression under air or hypoxic conditions, which was determined by elevated expression of caspase-3, increased TUNEL-positive cells, ultrastructural changes of neuronal cell death and loss of Nissl staining neuronal in infant SD rat brains. However, in propofol-oxygen group and all control groups, no significant apoptosis were observed. These findings indicated that propofol per se or hypoxia per se did not directly induce significant apoptosis. However, propofol-induced attenuation of respiration could produce lower oxygen concentrations in the blood under air or mild hypoxia conditions and thereby result in neuronal degeneration. So, it is important to supply with supplementary oxygen during propofol anesthesia.

Role of Nitric Oxide Synthase in Bladder Pathologic Remodeling and Dysfunction Resulting From Partial Outlet Obstruction

OBJECTIVES To investigate the relationship between nitric oxide synthase (NOS) and oxidative stress and pathologic remodeling in the partial obstructed bladder of a rat model. METHODS We surgically established partial bladder outlet obstruction (PBOO) in 2 groups of rats and allowed it to persist for 3-6 weeks. Normal and sham-operated rats served as the controls. Each group contained 6 rats for a total of 24 rats. Cystometry was used to evaluate the bladder function. The bladders were removed, and histopathologic measurements were performed to evaluate bladder hypertrophy and fibrosis and NOS immunolocalization. Biochemical measurements were used to evaluated NOS mRNA and activity and the oxidative stress level. RESULTS The obstructed rats experienced significant increases in bladder weight, muscle hypertrophy, and deposits of collagen fibers compared with the normal and sham-operated groups. PBOO debilitated bladder contractibility, increased the residual urine volume and voiding interval, decreased the voiding volume, and caused poor bladder emptying, with an increased residual urine volume and decompensated bladder in the PBOO rats at 6 weeks. The elevation in malondialdehyde and reduction in superoxide dismutase activity in the PBOO rats suggested that oxidative stress injury occurred in the obstructed bladder. Lower inducible NOS and endothelial NOS (eNOS) mRNA expression was demonstrated through quantitative polymerase chain reaction. In particular, eNOS was significantly downregulated in the PBOO rats compared with the normal and sham-operated rats. The normal and PBOO bladder tissues did not express detectable levels of neuronal NOS mRNA or exhibit neuronal NOS immunoreactivity. The total NOS activity had decreased progressively in the PBOO groups in conjunction with the significantly decreased eNOS activity compared with that in the normal and sham-operated groups. CONCLUSIONS These findings suggest that decreases in NOS activity and expression (mainly of eNOS) concomitant with increases in reactive oxygen species generation represent the underlying pathogenic mechanism of obstructed bladder remodeling and dysfunction.

Urban fine particulate matter exposure causes male reproductive injury through destroying blood-testis barrier (BTB) integrity.

Blood-testis barrier (BTB) provides a suitable microenvironment for germ cells that is required for spermatogenesis. Exposure to particulate matter (PM) is recognized to occasion male reproductive impairment, but the mechanism of which remains unclear. Male Sprague-Dawley (SD) rats were used to establish animal models with PM2.5 exposure concentration of 0, 10, and 20mg/kg.b.w. once a day for four weeks. Success rate of mating, sperm quality, epididymal morphology, expressions of spermatogenesis markers, superoxide dismutases (SOD) activity and expression in testicular tissues, and expressions of BTB junction proteins were detected. In addition, in vitro experiments were also performed. After PM2.5 treatment, reactive oxygen species (ROS) production and apoptosis of Sertoli cells were analyzed. Our results indicated that after PM2.5 exposure male rats presented inferior uberty and sperm quality, with decreased expressions of spermatogenesis markers, escalated SOD activity and expression levels, and reduced expressions of tight junction, adherens junction, and gap junction proteins in testicular tissues. Meantime, PM2.5-treated Sertoli cells displayed increased SOD production and apoptosis. PM2.5 exposure engenders male reproductive function injury through breaking BTB integrity.

Transforming growth factor-β3 expression up-regulates on cleft palates induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been shown to induce cleft palate, in which the molecular etiology of the defect is poorly characterized. Recently, transforming growth factor-β3 (TGF-β3) has been indicated to play an essential role in the development of palatal shelves. In this developmental toxicity study, we investigated the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the expression of TGF-β3 in fetal mice. Pregnant C57BL/6 mice were exposed to corn oil or TCDD (32 μg/kg/day 64 μg/kg/day, per os) at embryonic day 10 (ED10), a drastic inhibition of palatal shelves was induced. By using RT-PCR (reverse transcription-polymerase chain reaction) and Western blot, the expressions of TGF-β3 was investigated. We found that the expression of TGF-β3 was gradually up-regulated in TCDD-treated group. These results suggest that cleft palate can be induced by TCDD exposure, the modification of TGF-β3 is related to its pathogenesis.

Protective Effects of Vitamin E against reproductive toxicity induced by di(2-ethylhexyl) phthalate via PPAR-Dependent Mechanisms

Abstract Objective: To investigate the protective/ameliorative effects of vitamin E on di-2-(ethylhexyl) phthalate (DEHP)-induced reproductive toxicity, particularly in testicular toxicity in male rats, emphasizing peroxisome proliferator-activated receptor (PPAR)-dependent mechanism. Methods: Sprague-Dawley females were exposed by oral route to DEHP alone or associated with vitamin E from gestation day (GD) 12.5 to postnatal day (PND) 3 according to the following treatment regimens: vehicle control (corn oil), vitamin E (200 mg/kg)+corn oil, DEHP (500 mg/kg)+corn oil, and DEHP (500 mg/kg)+vitamin E (200 mg/kg)+corn oil. Variables including litter size, sex ratio, pup weight, post-implantation losses, and the number of viable pups were also assessed. Three male pups per litter were randomly selected and necropsied to measure paired testes weight, apoptosis, and gene expression on PND 3. To evaluate the long-term protective effects of vitamin E, three randomly selected males were necropsied to measure testis histology on PND 70. Results: Supplementation of vitamin E (200 mg/kg) reduced malformations, increased testes weight and prevented the maternal bodyweight loss induced by DEHP. Litter size, sex ratio, and number of viable pups were unaffected, but vitamin E co-administration declined testicular cell apoptosis, decreased the PPARs expression, and protected testis histology. Conclusions: Vitamin E cotreatment showed protective effects against DEHP-induced testicular toxicity, including reproductive malformations, testicular weight, apoptosis and histology, and the mechanisms maybe associated with PPARs.

Di-(2-ethylhexyl) phthalate (DEHP)-induced testicular toxicity through Nrf2-mediated Notch1 signaling pathway in Sprague-Dawley rats

Di‐(2‐ethylhexyl) phthalate (DEHP) is an environmental endocrine disruptor widely used in China that is harmful to the male reproductive system. Many studies have shown that DEHP causes testicular toxicity through oxidative stress, but the specific mechanism is unknown. Because the Notch pathway is a key mechanism for regulating cell growth and proliferation, we investigated whether Notch is involved in DEHP‐induced testicular toxicity and whether vitamins E and C could rescue testicular impairment in Sprague–Dawley (SD) rats. Compared with the control group, we found that DEHP exposure induced testicular toxicity through oxidative stress injury, and it decreased the testosterone level (P < .01) and upregulated nuclear factor‐erythroid 2 related factor (Nrf2) expression (P < .01). Therefore, because oxidative stress might be the initiating factor of DEHP‐induced testicular toxicity, treatment with the antioxidant vitamins E and C activated the Notch1 signaling pathway in the testis and in Leydig cells. Treatment with vitamins E and C normalized the oxidative stress state after DEHP exposure and restored testicular development to be similar to the control group. In summary, antioxidant vitamins E and C may be used to treat DEHP‐induced testicular toxicity.

Diagnosis and treatment of urethral prolapse in children: 16 years’ experience with 89 Chinese girls

Abstract Objective: To review our experience and results in the diagnosis and treatment of urethral prolapse (UP) in Chinese girls. Patients and methods: We conducted a retrospective chart review of 89 consecutive girls (aged <16 years) with UP and without other complications, who received treatment for UP from January 1999 to January 2015 (a study period of 16 years) at the Children’s Hospital of Chongqing Medical University, China. Data analysed included: age, symptoms, clinical findings, predisposing factors, management, and outcomes. Results: The presenting symptoms in the 89 girls were: mass (54 girls), bleeding (34), and dysuria/straining at micturition (one). In all, 14 patients received conservative treatment as their symptoms were mild, and 75 were successfully treated by excision of the prolapsed urethral mucosa or ligation over a Foley catheter, as their symptoms were severe and recurred too frequently to be managed conservatively. The mean postoperative length of stay for ligation was 7.76 days and for excision was 4.57 days. Ligation over a Foley catheter had a longer hospital stay. Conclusions: UP is a rare condition occurring in prepubertal girls, evidenced by a urethral mass and bleeding. Increased physician awareness and early recognition of UP avoids unnecessary examinations and patient anxiety.

A 22-year retrospective study: educational update and new referral pattern of age at orchidopexy.

To determine the current age at orchidopexy in China and whether changing targets have altered practice, as research suggesting progressive deterioration in an undescended testis (UDT) has led to the reduction in the target age for orchidopexy to 6–12 months but it is still unknown whether changing targets have altered practice.