Immature rat Leydig cells are intrinsically less sensitive than adult Leydig cells to ethane dimethanesulfonate.

Leydig cells from immature rat testes appear to be insensitive to doses of ethane-1,2-dimethanesulfonate (EDS) which eliminate Leydig cells from adult rat testes. We sought to determine whether this differential response to EDS is intrinsic to the Leydig cell or mediated by other intra- or extratesticular differences between adult and immature rats. To differentiate among these possibilities, Leydig cells were exposed to EDS (1) in vivo, (2) through in vitro testicular perfusion, or (3) in highly purified Leydig cell primary cultures. Four days after ip injections of 85 mg EDS/kg body wt Leydig cells were eliminated from testes of adult, but not immature rats. Total androgen production by testes perfused in vitro with 94 micrograms EDS/ml was dramatically reduced in adult, but not immature rats. Highly purified adult, but not immature, rat Leydig cells were far more sensitive to the effects of EDS on luteinizing hormone-stimulated androgen production (functional effects; apparent EC50 = 94 for adult and 407 micrograms/ml for immature rat Leydig cells) and on [35S]methionine incorporation (cytotoxic effects; apparent EC50 = 140 for adult and 1000 micrograms/ml for immature rat Leydig cells). Finally, the in vitro effects of EDS were both cell type and chemical specific. Since the differential response of adult and immature rat Leydig cells to EDS was manifest in vivo, during in vitro testicular perfusion, and in highly purified Leydig cell primary cultures, we conclude that immature rat Leydig cells are intrinsically less sensitive to the specific cytotoxic effects of EDS than adult rat Leydig cells.     

Multiple effects of ethane dimethanesulfonate on the epididymis of adult rats

Ethane dimethanesulfonate (EDS), a Leydig cell toxicant which results in transient infertility, was used in a 4 day postexposure experimental protocol designed to identify any effects this compound might exert on the epididymis. The techniques of efferent duct ligation and testosterone (T) implantation were used to negate the role of testicular effects on the epididymal parameters. Numerous evaluations were performed including light and electron microscopy, computer assisted sperm motion analyses, and electrophoresis of sperm membrane proteins. EDS was shown to affect the epididymis in a dose-dependent fashion. The action of EDS on the epididymis is in part due to Leydig cell cytotoxicity and the resulting decrease in circulating androgen since T implantation prevented some of the changes in sperm proteins and motility. However, neither efferent duct ligation nor T implantation prevented the formation of sperm granulomas in the caput epididymidis, the distinct morphological alterations of the corpus epididymidis, the modification of certain sperm membrane proteins, or the decrease in the progressive motility and velocity of sperm following EDS treatment. Although we cannot prove these effects of EDS are due to a direct action on the epididymis, it is now clear that EDS has a distinct action on the epididymis which is unrelated to circulating T or testicular fluid.     

Testicular effects of the Leydig cell toxicant ethane dimethanesulphonate given to neonatal rats.

Neonatal rats were injected with either 50 mg/kg ethane dimethanesulphonate (EDS) or vehicle on days 1 to 5 inclusive or on day 1 alone. Studies were made on days 6, 28, and 63 of testicular structure; related endocrinologic parameters were measured in the day 1 to 5 treated animals only. Leydig cells and their activities were identified by cell counts using sections stained for 3 beta-hydroxysteroid dehydrogenase, hCG binding to LH receptors in testicular homogenates, and assays of intratesticular testosterone, plus pituitary and/or serum concentrations of testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH). Given on days 1 to 5, EDS reduced Leydig cell populations estimated by morphometry and 125I-HCG binding, and testicular and body weights between days 6 and 63, and permanently retarded the development of the seminiferous epithelium. Decreases of serum and intratesticular testosterone occurred with homeostatic rises in FSH and LH. Injection on day 1 reduced Leydig cell numbers only on day 6 although body weight remained retarded. The data illustrate the susceptibility of the developing rat testis to the cytotoxicant EDS; whether this is related to withdrawal of androgen production or nonspecific cytotoxicity remains to be evaluated.     

Inhibitory effects of mono-ethylhexyl phthalate on steroidogenesis in immature and adult rat Leydig cells in vitro

Di-2-ethylhexyl (DEHP) phthalate, one of the phthalates most widely distributed in our general environment, causes reproductive toxicity that is attributable to the action of its primary metabolite, mono(2-ethylhexyl) phthalate (MEHP). Here, we have investigated the effects of MEHP on steroidogenesis by primary cultures of immature and adult rat Leydig cells. In both cases MEHP (250muM) was found to inhibit stimulation of androgen production evoked by human chorionic gonadotropin (hCG). This was associated with decreased expression of steroidogenic acute regulatory (StAR) protein and reduced transport of cholesterol into mitochondria but no detectable adverse effect on steroidogenic enzymes. Moreover, upon exposure to MEHP alone, 5alpha-reductase activity was decreased in immature, but not in adult Leydig cells. All together, our findings demonstrate that MEHP exerts suppressive effects on hCG-activated steroidogenesis in primary cultures of immature and adult rat Leydig cells and suppresses 5alpha-reductase activity in immature and not of adult rat cells. This may partly explain the anti-androgenic effects of DEHP in vivo and indicate a higher susceptibility in younger subjects.     

In vivo and in vitro effects of cicletanine in spontaneously hypertensive rats

Oral treatment for 2 weeks with cicletanine [1,3-dihydro-6-methyl-7-hydroxy-3-(4-chloro-phenyl)furo(3,4-c)pyridine] at 30 mg/kg/day delayed the onset of hypertension in spontaneously hypertensive rats (SHR) (15.7 mmHg, p less than 0.001). This antihypertensive effect was increased when the animals were maintained on a high-salt diet (40.8 mmHg, p less than 0.001). The ability of cicletanine to alter calcium movements in phenylephrine (PE)- and angiotensin II (ANGIO)-triggered contraction was tested on isolated SHR aorta. PE (1 microM) and ANGIO (0.1 microM) induced a phasic contraction in calcium-free medium due to intracellular calcium release. Upon addition of calcium (2.5 mM) a second sustained (PE) or biphasis (ANGIO) contraction was observed. This second contraction was dependent on extracellular calcium influx. Cicletanine (0.1-0.3 mM) both reduced the phasic (77%, p less than 0.001 for PE; 68%, p less than 0.05 for ANGIO with cicletanine 0.3 mM) and the second contraction elicited by the two agonists (27%, p less than 0.001 for PE; 84%, p less than 0.001 for ANGIO with cicletanine 0.3 mM). These results suggest that in addition to its stimulatory effect on prostaglandin, a direct vascular action of cicletanine could also be involved in the antihypertensive properties of the drug.     

In vivo and in vitro effects of delta9-tetrahydrocannabinol on rats liver microsomal drug-metabolizing enzymes.

The in vivo and in vitro effects of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) on rat liver microsomal dimethylaniline-N-demethylase, p-nitroanisole-O-demethylase and aniline hydroxylase activities were studied. In vivo acute administration of Δ⁹-THC produced a marked inhibitory effect of these drug-metabolizing enzyme activities at the higher dose (50 mg/kg) after 6 hr of ip injection. The inhibition was of mixed type for the two demethylases and noncompetitive in case of aniline hydroxylase, whereas comparatively fewer inhibitory effects on these enzyme activities were observed at the lower dose (10 mg/kg). Chronic treatment with Δ⁹-THC for 21 days (10 mg/kg/day) competitively inhibited the N- and O-demethylase activities but had no inhibitory effect on aniline hydroxylase. Under in vitro conditions of drug treatment at doses of 2, 4, and 8 μg/mg of protein, two demethylase activities were found to be inhibited in a competitive manner whereas comparatively less and mixed type of inhibition was observed with aniline hydroxylase only at higher doses of the drug. These results suggest that Δ⁹-THC changes the conformation of the hepatic microsomal membrane in a characteristic way, and there exists a qualitative difference between the two substrate-binding sites of the microsomal membrane regarding their interaction with a highly lipophilic drug like Δ⁹-THC.     

In vivo and in vitro toxicity of decabromodiphenyl ethane,a flame retardant

Toxicity of a relative new flame retardant, namely decabromodiphenyl ethane (DBDPE), marketed as an alternative to decabromodiphenyl ether (BDE‐209) was assessed both in vivo and in vitro using the freshly separated fish hepatocyte assay and standardized water flea and zebrafish egg‐larvae tests. The fish hepatocyte assay, based on the synthesis and secretion of vitellogenin from isolated male liver cells produced a clear dose‐response curve in the presence of DBDPE. DBDPE induced the induction of hepatic ethoxyresorufin‐O‐deethylase (EROD) activity at low test concentrations, but started to inhibit the activity at higher concentrations. Also, the induction of the hepatocyte conjugation activity, uridinediphosphoglucuronosyltransferase (UDPGT), was induced with no signs of inhibition even at the highest test concentration. The reduced EROD activity resulted in a drop in the production of vitellogenin by the cells. In vivo tests showed that DBDPE was acutely toxic to water fleas, the 48 h EC‐50 value being 19 μg/L. Moreover, DBDPE reduced the hatching rates of exposed zebra‐fish eggs and raised significantly the mortality of hatched larvae. Because there is hardly any information available on the effects of DBDPE on the aquatic environments, it is crucial to obtain more data on the effects and effective concentrations of DBDPE along with its occurrence in the environment. Such data would enable reliable assessments of the risks posed by this flame retardant. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 333–338, 2010.     

In vitro and in vivo antimetastatic effects of Terminalia catappa L. leaves on lung cancer cells.

Terminalia catappa L. was a popular folk medicine and has several proven biological activities including antioxidant and anti-inflammatory. The present study investigated the effect of the extract of T. catappa leaves (TCE) on invasion and motility of tumor cells to find that TCE exerted a dose-dependent inhibitory effect on the invasion and motility of highly metastatic A549 and Lewis lung carcinoma (LLC) cells. To further investigate the precise involvement of TCE in tumor metastasis, A549 and LLC cells were treated with TCE at various concentrations, up to 100 microg/mL, for a specified period and results from zymography and Western blotting showed that a TCE treatment may decrease the expressions of matrix metalloproteinase-2, -9, urokinase plasminogen activator and their endogenous inhibitors, that is tissue inhibitor of metalloproteinase-2 and plasminogen activator inhibitor-1, in a concentration-dependent manner. Furthermore, the inhibitory effect of TCE on the growth and metastasis of LLC cells in vivo was proven. These results indicated that TCE could be applied to be a potential antimetastatic agent.     

In vivo and in vitro effects of amrinone and milrinone on hepatic xenobiotic metabolism in rats

Studies were performed on the response of hepatic xenobiotic metabolizing enzymes to in vitro and in vivo exposure to amrinone and milrinone, two new inotropic compounds used in congestive heart failure. Both drugs exerted selective effects on various cytochrome P-450-dependent metabolic activities as well as conjugating pathways. Aminopyrine N-demethylation was selectively inhibited by in vitro addition of milrinone but not amrinone, and laurate hydroxylation was inhibited by both drugs. Cytosolic glutathione-S-transferase activity was profoundly inhibited by in vitro addition of both drugs. In vivo administration of either drug did not lead to significant inhibition of the pathways studied other than laurate hydroxylation which was depressed 20-30%. Irreversible binding of [14C]-amrinone-derived radioactivity to microsomal protein was partially NADPH-dependent. Inhibition by SKF 525-A, alpha-naphthoflavone and various antioxidants was observed. No binding of [14C]-milrinone-derived radioactivity was seen. It is suggested that amrinone may selectively inhibit certain hepatic drug-metabolizing enzymes through metabolic electrophilic intermediates.     

In vitro and in vivo anticalcification effects of novel bishydroxyiminophosphonates.

Some geminal bisphosphonates are used clinically for a number of important bone- and/or calcium-related diseases; however, side effects and lack of selectivity impede their wide use. This work reports the synthesis and evaluation of bishydroxyiminophosphonates (e.g., adipoyl- and suberoylbisphosphonate dioximes). These compounds significantly inhibited hydroxyapatite formation and dissolution in vitro and the calcification of bioprosthetic tissue implanted subdermally in rats. The compounds reported in this paper are less active than the structurally related bisacylphosphonates. The results of this work indicate that the introduction of oxime groups adjacent to the phosphonic function in long-chain bisphosphonates confers calcium interaction capabilities and that complete ionizability of a bisphosphonate may enhance its biological activity.     

In vitro/in vivo effects of 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity of mice.

The activity of aryl hydrocarbon hydroxylase (AHH) in mouse liver microsomes was assayed in vitro in the presence of 7,8-benzoflavone (7,8-BF). The mice had been previously treated with the AHH inducer 3-methylcholanthrene (MC), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or vehicle (olive oil) alone. The effects of 7,8-BF on the AHH activity were markedly different according to the genetic responsiveness of the mice towards aromatic hydrocarbons (Ah). 7,8-BF had either an inhibitory or an enhancing effect on AHH, depending on the Ah responsiveness and previous treatment with MC or TCDD. In contrast, a single administration of 7,8-BF induced microsomal AHH, but the effect was much lower than MC or TCDD in both strains of mice. Simultaneous treatment or pre-treatment with 7,8-BF produced an inhibitory effect on AHH induction by MC or TCDD. Post-treatment with 7,8-BF inclined to promote the induction of AHH by MC or TCDD. These results suggest that the inhibitory effect of 7,8-BF is more exaggerated in vitro than in vivo. Inhibitory effects would be limited to AHH induction from MC or TCDD in in vitro studies, while they would depend on the time of application or Ah responsiveness in studies in vitro.     

In vitro and in vivo effects of ketamine on generation and function of dendritic cells

The question about how intravenous anesthetic reagents affect the development and function of dendritic cell subsets still has no comprehensive answers. Bone marrow cells differentiated with FMS-like tyrosine kinase 3 ligand in vitro represented the steady-state dendritic cell subsets. The effects of ketamine on the generation and function of dendritic cell subsets were investigated. We found that dendritic cell subsets responded to the anesthetic reagent ketamine in several aspects: 1) The in vitro and in vivo development of plasmacytoid dendritic cells were inhibited by ketamine at high concentrations; 2) The endocytosis of dendritic cells were not influenced by ketamine at concentrations from 50 - 200 μM; 3) The maturation markers of conventional dendritic cells were not changed by ketamine upon LPS or CpG stimulation, although the cytokines mRNA profiles were affected; 4) The allogenic-stimulatory activity of dendritic cells was suppressed by ketamine. In conclusion, ketamine hampered plasmacytoid dendritic cell subset development both in vivo and in vitro. The dendritic cells maturation and downstream responses towards different toll-like receptor stimuli were differently regulated by ketamine treatment.     

Cardiovascular effects of ketanserin on normotensive rats in vivo and in vitro.

In this work, we report for first time that: (1) low doses of ketanserin (0.2 mg/kg) produce a transient hypotensive response in anaesthetized rats, which is basically due to the blockade of 5-hydroxytryptamine (2A) (5-HT)2A receptors, whereas high doses (1 mg/kg) of ketanserin cause a sustained hypotension also mediated by the blockage of alpha1-adrenergic receptors; (2) the in vitro vasorelaxant action of high concentrations of ketanserin (>10 microM) involves Ca2+ antagonism, which may also be responsible, at least in part, for the inhibition of high-K+-induced 45Ca2+ uptake, the inhibition of Ca2+-induced contractions in initially Ca2+-free high-K+ medium, and the negative chronotropic effects on isolated atria. This Ca2+ antagonistic activity does not seem to contribute to the in vivo cardiovascular effects of ketanserin at therapeutic doses.     

In vivo effects of indomethacin--II. Antioxidant enzymes in metal-deficient rats.

1. The in vivo effects of indomethacin on the activity of antioxidant enzymes in erythrocytes, liver and small intestinal mucosa of rats fed a metal-deficient diet were studied. 2. Metal deficiency led to a significant decrease in the activity of the enzymes studied. 3. Neither with the "ulcerogenic" nor with the "therapeutic" dose of indomethacin significant alterations in the enzyme activity were observed. 4. The oral treatment of metal-deficient rats with a copper complex of indomethacin caused a significant increase in the activity of the enzymes studied. 5. The results suggest the participation of indomethacin in the regulation and redistribution of metals in the organism, which is probably effected through in vivo chelation of endogenous metals.     

In vitro effects of trichothecenes on human dendritic cells.

The aim of this work was to study the in vitro effects of trichothecenes on human dendritic cells. Trichothecenes are mycotoxins produced by fungi such as Fusarium, Myrothecium, and Stachybotrys. Two aspects have been explored in this work: the cytotoxicity of trichothecenes on immature dendritic cells to determine IC 50 (inhibition concentration), and the effects of trichothecenes on dendritic cell maturation process. Two mycotoxins (T-2 and DON) known to be immunotoxic have been tested on a model of monocyte-derived dendritic cells culture. Cytotoxic effects of T-2 toxin and DON on immature dendritic cells showed that DON is less potent than T-2 toxin. The exposure to trichothecenes during dendritic cell maturation upon addition of LPS or TNF-alpha markedly inhibited the up-regulation of maturation markers such as CD-86, HLA-DR and CCR7. Features of LPS or TNF-alpha -mediated maturation of dendritic cells, such as IL-10 and IL-12 secretions and endocytosis, were also impaired in response to trichothecenes treatment. These results suggest trichothecenes have adverse effects on dendritic cells and dendritic cell maturation process.     

芦荟多糖对大鼠骨关节炎治疗作用的体内和体外研究 #br#

目的 通过体外和体内实验探究芦荟多糖（APS）对大鼠骨关节炎（OA）的治疗作用。方法 体外分离SD 乳鼠的关节软骨细胞,培养至2代后,通过CCK-8法筛选实验组APS安全剂量。后续通过检测DNA含量和糖胺聚糖 （GAG）分泌量评估软骨细胞的增殖和基质降解情况,实时荧光定量PCR检测OA相关基因表达情况,酶联免疫吸附 测定（ELISA）法检测炎症因子水平;通过HE染色、番红O和免疫荧光染色等来观察其抗炎和软骨保护效果;并进一 步在SD大鼠骨关节炎模型中探究其作用效果。结果 通过CCK-8法筛选出剂量为5、10、20 g/L的APS作为低、中、 高剂量组。各剂量组的DNA含量均显著高于模型组（P＜0.05）;高剂量组GAG分泌量高于模型组（P＜0.05）。高剂 量组的蛋白聚糖（ACAN）和Ⅱ型胶原（COL2A1）基因表达水平相对模型组显著上调（P＜0.05）,而肿瘤坏死因子 （TNF）-α、白细胞介素（IL）-6、基质金属蛋白酶（MMP）-3和MMP-13基因表达显著下调（P＜0.05）。低、中、高剂量 组TNF-α和IL-6的分泌量显著低于模型组（P＜0.05）,HE和番红O染色也显示APS实验组的细胞形态较模型组好, MMP-13免疫荧光显示高剂量组的表达量显著低于模型组（P＜0.05）。体内实验软骨组织番红O染色及国际骨关节 炎研究学会（OARSI）软骨损伤评分结果显示APS干预的实验组关节软骨损伤程度明显低于模型组（P＜0.05）。结论 APS对OA具有一定的抗炎和软骨保护作用。     

In vitro and in vivo antitumor effects of bisphosphonates

Bisphosphonates are powerful inhibitors of osteoclast-mediated bone resorption. They are currently used in the palliative treatment of bone metastases. However, bisphosphonates do not only act on osteoclasts. There is now extensive in vitro preclinical evidence that bisphosphonates can act on tumor cells: they inhibit tumor cell adhesion to mineralized bone as well as tumor cell invasion and proliferation. Bisphosphonates induce also tumor cell apoptosis and stimulate gammadelta T cell cytotoxicity against tumor cells. In vivo, bisphosphonates inhibit bone metastasis formation and reduce skeletal tumor burden. This may reflect direct antitumor effects and indirect effects via inhibition of bone resorption. In addition, bisphosphonates inhibit experimental angiogenesis in vitro and in vivo. Understanding the molecular mechanisms through which bisphosphonates act on tumor and endothelial cells will be undoubtedly an important task in the future. It will allow the design of clinical trials to investigate whether the antitumor activity of bisphosphonates can be realized in the clinical setting.     

In vitro and in vivo anti-inflammatory effects of andrographolide

Andrographolide – the major active principle isolated from the plant Andrographis paniculata, has been shown to possess a strong anti-inflammatory activity. The possibility that the drug may affect asthmatic inflammation, through inhibition of the relevant inflammatory cytokines, has not been explored. The purpose of this study was, firstly, to investigate the ability of andrographolide to inhibit the release of inflammatory cytokines in vitro in a model of non-specific inflammation and subsequently to determine whether such effect can also be exerted in vivo in allergic lung inflammation.LPS-induced TNF-α and GM-CSF release from mouse peritoneal macrophages was inhibited by andrographolide in a concentration-dependent manner. The concentration of the drug producing 50% inhibition was 0.6 μM for TNF-α and 3.3 μM for GM-CSF. The maximal inhibition achieved (at 50 μM) was 77% and 94%, respectively, for the two cytokines. The drug was as efficacious as dexamethasone, but about 8–12 times less potent. The drug also suppressed LPS-induced expression of mRNA for the two cytokines, suggesting that this effect may contribute to the mechanism underlying its anti-inflammatory effects. In the in vivo study, intra-peritoneal treatment of ovalbumin-immunized and nasally-challenged mice with andrographolide significantly inhibited the elevation of bronchoalveolar fluid (BAF) levels of TNF-α and GM-CSF in a dose-dependent manner, with 30 mg/kg producing an inhibition of 92% and 65% of the cytokines, respectively) and almost completely abolishing the accumulation of lymphocytes and eosinophils. These results provide evidence that andrographolide is an effective anti-inflammatory drug that is active in vitro and in vivo, and affects both non-specific as well as antigen/antibody-dependent lung inflammation. Thus, andrographolide has the potential to be used in a variety of inflammatory conditions, including allergic lung inflammation.