Effects of di-butyl phthalate on the reproductive system of adolescent male rats / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the effects of di-butyl phthalate (DBP) on the reproductive system of adolescent male rats.</p><p><b>METHODS</b>Sprague-Dawley (SD) rats aged 5 weeks were assigned to receive corn oil (vehicle control) or DBP orally at 10, 100 and 500 mg/(kg x d) for 30 days. After the exposure, the testis, epididymis, liver and pituitary of the rats were weighted and their ratios to the body weight obtained. Histopathological changes of the testis and epididymis were examined by Hematoxylin-eosin staining, the levels of testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) in the serum were measured by radioimmunoassay, and the relative mRNA expressions of the steroidogenesis acute regulatory protein (StAR), proliferating cell nuclear antigen (PCNA), cytochrome P450 cholesterol side chain cleavage enzyme (P450scc) and scavenger receptor (SR) were detected by real-time quantitative RT-PCR.</p><p><b>RESULTS</b>DBP induced significant histopathological changes in the testicular tissue at 100 and 500 mg/(kg x d), and decreased the testicular and epididymal weights, inhibited the mRNA expressions of StAR and PCNA, reduced the levels of T and LH, and elevated the level of FSH at 500 mg/(kg x d). At the dose of 10 mg/(kg x d), DBP increased serum LH and FSH and the mRNA expression of P450scc. While the SR mRNA expression showed no significant changes in all the groups.</p><p><b>CONCLUSION</b>High level of DBP has apparent toxic effect on reproductive system of male rats. Low - dose DBP can increase the level of serum gonadotropin LH and affect the mRNA expression of P450scc in the testis.</p>

Fenvalerate affects sperm motility in SD rats / 中华男科学杂志

<p><b>OBJECTIVE</b>To observe the direct effects of fenvalerate (Fen) on sperm motility in SD rats.</p><p><b>METHODS</b>Sperm were isolated from caudal epididymides of healthy adult male rats with the diffusion method. The motility parameters of the isolated sperm, such as VCL, VSL, VAP, BCF, STR and LIN, were monitored by computer-assisted sperm analysis (CASA) system after 1, 2 and 4 h Fen-exposure in vitro at concentrations of 0, 1, 4, 16 and 64 micromol/L respectively.</p><p><b>RESULTS</b>After 1 and 2 h Fen-exposure, VSL, BCF, STR and LIN decreased significantly at 64 micromol/L compared with the control group. After 4 h Fen-exposure, the motility parameters VCL, VSL, BCF, STR and LIN dropped progressively at 64 micromol/L, and VCL declined markedly at 16 micromol/L. However, only VCL and STR showed alterations in a time-response manner.</p><p><b>CONCLUSION</b>Fen may affect the caudal epididymal sperm and produce a direct toxic effect on sperm motility in SD rats.</p>

Advances in the study of steroidogenic acute regulatory protein / 中华男科学杂志

The steroidogenic acute regulatory (StAR) protein is an essential component in the regulation of steroid biosynthesis in adrenal and gonadal cells. The StAR protein has a high tissue specificity, located on the mitochondrial membranes of some relative cells. It regulates the transfer of cholesterin from extracellular into intracellular and plays a dominant role in steroidogenic synthesis. Recent studies have also shown that the transcription and expression of StAR are modulated not only through the cAMP-PKA dependent pathway, but also by multiple hormones and cytokines, which contributes to the regulation of cholesterin synthesis.

Metabolism of terephthalic acid and its effects on CYP4B1 induction / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investgate the metabolism of terephthalic acid (TPA) in rats and its mechanism. Methods Metabolism was evaluated by incubating sodium terephthalate (NaTPA) with rat normal liver microsomes, or with microsomes pretreated by phenobarbital sodium, or with 3-methycholanthrene, or with diet control following a NADPH-generating system. The determination was performed by high performance liquid chromatography (HPLC), and the mutagenic activation was analyzed by umu tester strain Salmonella typhimurium NM2009. Expression of CYP4B1 mRNA was detected by RT-PCR. Results The amount of NaTPA (12.5-200 micromol x L(-1)) detected by HPLC did not decrease in microsomes induced by NADPH-generating system. Incubation of TPA (0.025-0.1 mmol x L(-1)) with induced or noninduced liver microsomes in an NM2009 umu response system did not show any mutagenic activation. TPA exposure increased the expression of CYP4B 1 mRNA in rat liver, kidney, and bladder.</p><p><b>CONCLUSION</b>Lack of metabolism of TPA in liver and negative genotoxic data from NM2009 study are consistent with other previous short-term tests, suggesting that the carcinogenesis in TPA feeding animals is not directly interfered with TPA itself and/or its metabolites.</p>

Effects of terephthalic acid on rat lipid metabolism / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effect of terephthalic acid (TPA) on lipid metabolism in Sprague-Dawley (SD) rats.</p><p><b>METHODS</b>Five groups of SD rats that ingested 0%, 0.04%, 0.2%, 1%, and 5% TPA, respectively, were included in a 90-day subchronic feeding study. Effects of TPA on levels of serum protein, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL), total antioxidative capability (T-AOC), superoxide dismutase (SOD) and malondialdehyde (MDA) were observed. Urine samples were collected and analyzed for concentration of ion.</p><p><b>RESULTS</b>TPA decreased the level of serum T-AOC in a dose dependent manner. The contents of serum and bladder MDA significantly decreased in 1% and 5% TPA ingestion groups. Serum CuZn superoxide dismutase (CuZnSOD) lowered in groups of 0.2%, 1%, and 5% TPA. TPA subchronic feeding had no significant influences on serum TC, LDL or HDL, but increased serum TG, TP and ALB after administration of 0.04% and/or 0.2% TPA. Concentrations of urinary Ca2+, Mg2+, Na+, and K+ were elevated in 1% and 5% TPA groups.</p><p><b>CONCLUSION</b>Antioxidative potential decreased after TPA exposure. MDA increase in serum and bladder tissues was one of the most important reactions in rats which could protect themselves against TPA impairment. The decrease of serum CuZnSOD was related to the excretion of Zn2+.</p>

Effects of dibutyl phthalate on sertoli cells of rat testis / 中华预防医学杂志

<p><b>OBJECTIVE</b>The present study was performed to examine functional and structural impairment of rat sertoli cells following dibutyl phthalate (DBP) exposure.</p><p><b>METHODS</b>The 6-week-old healthy male Sprague Dawley rats were randomly divided into 4 groups with 16 animals in each group. DBP dissolved in peanut oil was administered by gavage at doses of 0, 250, 500 and 1 000 mg/kg. After 2-week DBP treatment, half of the rats were sacrificed. The rest were killed following 4-week DBP exposure. Follicle stimulating hormone (FSH) was analysed by radioimmunoassay. The relative expression levels of androgen binding protein (ABP) mRNA and inhibin (INH)alpha mRNA were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The sertoli cell ultrastructures were observed by using transmission electron microscope (TEM).</p><p><b>RESULTS</b>FSH levels were increased after 4-week DBP exposure with significance at doses of 250 and 1 000 mg/kg. Sperm head count and daily sperm product were decreased significantly in 500 and 1 000 mg/kg groups. The expression levels of ABP mRNA were 0.89 +/- 0.15, 0.85 +/- 0.23, 0.54 +/- 0.17, 0.52 +/- 0.16 and 0.88 +/- 0.16, 0.61 +/- 0.12, 0.48 +/- 0.15, 0.47 +/- 0.11 for 0, 250, 500 and 1 000 mg/kg after 2- and 4-week DBP treatments respectively with significance at doses of 500 and 1 000 mg/kg (P < 0.01), while the levels of INHalpha mRNA were 0.88 +/- 0.16, 0.61 +/- 0.12, 0.48 +/- 0.15, 0.47 +/- 0.11 and 0.75 +/- 0.19, 0.56 +/- 0.16, 0.53 +/- 0.08, 0.45 +/- 0.10 with significance at all exposure groups (P < 0.01 or P < 0.05). In sertoli cells of rats exposed to 1 000 mg/kg DBP, TEM photos showed more lysosomes in cytoplasm, proliferated and expanded endoplasmic reticulum and nuclei malformation.</p><p><b>CONCLUSIONS</b>Sertoli cell should be one of the major toxic targets. Impairment of spermatogenesis caused by DBP should be partly due to the suppression of ABP and INHalpha biosynthesis.</p>

Effects of mono(2-ethylhexyl) phthalate on testosterone biosynthesis in leydig cells cultured from the rat testis / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the effects of mono(2-ethylhexyl) phthalate(MEHP), the primary metabolite of di(2-ethylhexyl) phthalate (DEHP), on testosterone biosynthesis in Leydig cells cultured from the Sprague Dawley rat testis.</p><p><b>METHODS</b>Based on the primary Leydig cell culture model, MEHP exposure groups involved control (0 micromol/L), 62.5, 125, 250, 500 and 1000 micromol/L. We observed mitochondria activity with the MTT method, measured the testosterone level with RIA and determined steroidogenesis acute regulatory protein (StAR) mRNA expression with RT-PCR.</p><p><b>RESULTS</b>After Leydig cells were exposed to MEHP for 24 hours, the activity of mitochondria enhanced evidently at 250 micromol/L and then declined markedly at 1000 micromol/L compared with the control group (P < 0.01). The testosterone level showed an increasing tendency in both basal and hCG-stimulated states with statistical significance at 250 and 500 micromol/L compared with the control group (P < 0.01). However, the expression of StAR mRNA appeared unchanged at 62.5, 125 or 250 micromol/L, but exhibited a decreasing tendency at 500 and 1000 micromol/L (P < 0.01).</p><p><b>CONCLUSION</b>ME- HP directly affected the activity of mitochondria and testosterone biosynthesis of the Leydig cells in vitro. StAR, the regulator of cholesterol transport into mitochondria, might not be responsible for the increase of testosterone biosynthesis induced by MEHP.</p>

Effect of fenvalerate on the ovarian calcium homeostasis and the serum steroid hormone / 中华预防医学杂志

<p><b>OBJECTIVE</b>To observe the effects of fenvalerate (Fen) on ovarian calcium homeostasis.</p><p><b>METHODS</b>hGLCs were obtained from pre-ovulatory follicles in an in vitro fertilization program, and were cultured for 72 hours. Changes in cellular [Ca(2+)]i induced by Fen in hGLCs were detected with laser scanning confocal microscopy (LSCM) by using the fluorescent Ca(2+) indicator fluo-3/AM. SD female rats were divided into four groups (control, 1/15LD(50), 1/50 LD(50) and 1/250 LD(50)) in experiment. The activity of ovarian Ca(2+)-ATPase and phosphorylase A (P-a) and the contents of calmodulin (CaM) were assessed after a 30-day Fen exposure. In addition, serum estradiol-17 beta (E(2)) and progesterone (P(0)) concentration were measured by radioimmunoassay, which the sampling rats were ensured at diestrus stage before killed according to vaginal smear.</p><p><b>RESULTS</b>20.0 and 2.0 micromol/L Fen induced the increased of [Ca(2+)]i in hGLC. This [Ca(2+)]i increase mostly resulted from Ca(2+) influx in the studied concentration. Fen had shown the inhibition effects on activity of Ca(2+)-ATPase in 1/250 LD(50) group (P < 0.001) while the activity of phosphorylase A (P-a) in treated groups had significantly enhanced than those of in control. The contents of CaM in ovaries were found to be increased in treated groups. E(2) in 1/250 LD(50) group were higher while P(0) in 1/15 LD(50) group were significantly lower (P < 0.05).</p><p><b>CONCLUSION</b>Exposure to Fen interferes the serum steroid hormone concentrations partly through calcium signal pathway.</p>