Vanadocene-mediated in vivo male germ cell apoptosis

Synthesis, structure and characterization of new dithiocarbazate-based mixed ligand oxidovanadium(iv) complexes: DNA/HSA interaction, cytotoxic activity and DFT studies

The synthesis, structure and characterization of mixed ligand oxidovanadium(iv) complexes [V^IVOL^1–2(L^N–N)] (1–3) are reported. With a view to evaluating their biological activity, their DNA/HSA interaction and cytotoxicity activity have been explored.

Vanadyl complexes discriminate between neuroblastoma cells and primary neurons by inducing cell-specific apoptotic pathways

Vanadium compounds have arisen as potential therapeutic agent for the treatment of cancers over the past decades. A few studies suggested that vanadyl complexes may discriminate between the cancerous and the normal cells. Here, we reported the investigation on the pro-apoptotic effect and the underlying mechanism of bis(acetylacetonato) oxovanadium(IV) ([VO(acac)₂]) on SH-SY5Y neuroblastoma cells in comparison with that of mouse primary cortex neurons. The experimental results revealed that [VO(acac)₂] showed about 10-fold higher cytotoxicity (IC50 ~16 μM) on the neuroblastoma cells than on normal neurons (IC50 ~250 μM). Further analysis indicated that the vanadyl complex suppressed the growth of neuroblastoma cells via different pathways depending on its concentration. It induced a special cyclin D-mediated and p53-independent cell apoptosis at <50 μM but cell cycle arrests at >50 μM. In contrast, [VO(acac)₂] promoted cell viability of primary neurons in the concentration range of 0-150 μM; while [VO(acac)₂] at hundreds of μM would cause neuronal death possibly via the reactive oxygen species (ROS)-mediated signal pathways. The extraordinary discrimination between neuroblastoma cells and primary neurons suggests potential application of vanadyl complexes for therapeutic treatment of neuroblastoma. In addition, the p53-independent apoptotic pathways induced by vanadyl complexes may provide new insights for future discovery of new anticancer drugs overcoming the chemo-resistance due to p53 mutation.

The effect of zinc oxide nanoparticles on mouse spermatogenesis

OBJECTIVE

To evaluate the effects of zinc oxide nanoparticles on mouse spermatogenesis.

METHODS

Thirty two adult male NMRI mice were used. Experimental Groups (ZNP-1-ZNP-3) received one of the following treatments daily for 35 days: 5, 50 and 300 mg/kg zinc oxide nanoparticles respectively. Control group received only distilled water. Epididymal sperm parameters, testicular histopathology, morphometric analysis and spermatogenesis assessments were performed for evaluation of the zinc oxide nanoparticles effects on testis.

RESULTS

Epididymal sperm parameters including sperm number, motility and percentage of abnormality were significantly changed in 50 and 300 mg/kg zinc oxide nanoparticles treated mice (p < 0.01). Histopathological criteria such as epithelial vacuolization, sloughing of germ and detachment were significantly increased in 50 and 300 mg/kg zinc oxide nanoparticles treated mice (p < 0.001). 300 mg/kg zinc oxide nanoparticles induced formation of multinucleated giant cells in the germinal epithelium. 50 and 300 mg/kg zinc oxide nanoparticles also caused a significant decrease in seminiferous tubule diameter, seminiferous epithelium height and maturation arrest (p < 0.001).

CONCLUSION

Zinc oxide nanoparticles act as testicular toxicant and further studies are needed to establish its mechanism of action upon spermatogenesis.

Effect of curcumin on dexamethasone-induced testicular toxicity in mice

CONTEXT

Curcumin is a yellow-orange polyphenol derived from turmeric [Curcuma longa L. (Zingiberaceaerhizomes)]. Turmeric is a main ingredient of Indian, Persian, and Thai dishes. Extensive studies within the last half a century have demonstrated the protective action of curcumin in many disorders of the body.

OBJECTIVE

This study evaluated the protective effect of curcumin on dexamethasone-induced spermatogenesis defects in mice.

MATERIALS AND METHODS

Thirty-two NMRI mice were randomly divided into 4 groups. The first (control) group received 1 mL/day of distilled water by intraperitoneal (i.p.) injection for 7 days. The second group received 200 mg/kg/day of curcumin (Cur) for 10 days. Third group received 7 mg/kg/day of dexamethasone (Dex) for 7 days. Forth group received 200 mg/kg of curcumin for 10 days after dexamethasone treatment. Testicular histopathology, morphometric analysis, head sperm counting, and immunohistochemistry assessments were performed for evaluation of the dexamethasone and curcumin effects.

RESULTS

Expression of Bcl-2 was significantly increased in the curcumin + dexamethasone group compared with dexamethasone-treated animals (p < 0.05). Dexamethasone induced spermatogenesis defects including epithelial vacuolizations, sloughing of germ cells, reduction of seminiferous tubule diameter, reduction in the number of sperm heads and significant maturation arrest (p < 0.001). Curcumin + dexamethasone treatment significantly prevented these changes (p < 0.05).

DISCUSSION AND CONCLUSION

The results of this study demonstrate that curcumin increases the expression of Bcl-2 protein, an important anti-apoptotic factor, and improves the spermatogenesis defects in dexamethasone treated mice. Curcumin has a potent protective effect against the testicular toxicity and might be clinically useful.

Toxic effects of Carthamus tinctorius L. (Safflower) extract on mouse spermatogenesis

OBJECTIVE

To evaluate the effects of aqueous extract of Carthamus tinctorius L., also named safflower, on mouse spermatogenesis.

METHODS

Sixteen adult male NMRI mice were used. Experimental group received Carthamus tinctorius L. extract at the dose of 200 mg/kg for 35 consecutive days and control group received only distilled water. Testicular histopathology, morphometric analysis and spermatogenesis assessments were performed for evaluation of the Carthamus tinctorius L. extract effects on testis.

RESULTS

Histopathological criteria such as epithelial vacuolization, sloughing of germ and detachment were significantly decreased in Carthamus tinctorius L. treated mice (p < 0.001). Carthamus tinctorius L. extract induced formation of multinucleated giant cells in the germinal epithelium. Carthamus tinctorius L. extract also caused a significant decrease in seminiferous tubule diameter, seminiferous epithelium height and maturation arrest (p < 0.001).

CONCLUSION

Carthamus tinctorius L. extract has toxic effects on mouse testicular tissue, and recommended to use it with caution if there is a reproductive problem.

Vanadocene complexes of amino acids containing secondary amino group: the first evidence of O,O-bonded carboxylic group to vanadocene(IV) moiety

Reaction of vanadocene dichlorides (Cp(2)VCl(2) and (eta(5)-C(5)H(4)Me)(2)VCl(2)) with amino acids containing secondary amino groups gives three types of complexes: a) compounds with N,O-bonded amino acid, b) O-bonded amino acids and c) O,O-bonded amino acid. The complexes with N,O-bonded amino acid and O-bonded amino acids were observed in the case of l-proline and N-methylglycine (NMG). Reactions with N-phenylglycine (NPG) give O,O-chelates as the sole products. All three types of the complexes were characterized by spectroscopic methods. Structures of [(eta(5)-C(5)H(4)Me)(2)V(O-Pro)][BPh(4)], [Cp(2)V(O-Pro)(2)][PF(6)](2), [Cp(2)V(N,O-NMG)][BPh(4)].MeOH, [(eta(5)-C(5)H(4)Me)(2)V(N,O-NMG)][BPh(4)].MeOH, [Cp(2)V(O-NMG)(2)][Cl](2).2H(2)O, [(eta(5)-C(5)H(4)Me)(2)V(O-NMG)(2)][Cl](2).H(2)O and [(eta(5)-C(5)H(4)Me)(2)V(O,O-NPG)][BPh(4)] were determined by X-ray crystallography.

Preclinical evaluation of a dual-acting microbicidal prodrug WHI-07 in combination with vanadocene dithiocarbamate in the female reproductive tract of rabbit, pig, and cat

The mucosal safety of the combination antiretroviral spermicide,WHI-07 [5-bromo-6-methoxy-5,6-dihydro-3'-azidothymidine-5'-(p-bromophenyl)-methoxy alaninyl phosphate] and vanadocene dithiocarbamate (VDDTC), was evaluated in 3 different animal models. Twenty-seven NZW rabbits in four subgroups were exposed intravaginally to a gel-microemulsion (GM) with and without three dose levels of WHI-07 plus VDDTC (0.5+0.06%, 1.0+0.12% and 2.0+0.25%) or 4% nonoxynol-9 (N-9; Conceptrol) for 14 consecutive days. Ten nonestrus gilts (Duroc) in three subgroups received either a single or daily intravaginal application of GM with and without 2.0% WHI-07 plus 0.25% VDDTC or 2.0% benzalkonium chloride (BZK)-containing gel for 6 and 4 consecutive days, respectively. Five cats received a single intravaginal application of GM incorporating 2.0% WHI-07 plus 0.25% VDDTC. Genital tract histopathology was performed in the pig and rabbit at the end of dosing period but after 18 weeks post-dosing in the cat. Porcine cervicovaginal lavage (CVL) fluid was obtained for up to 72 hours after a single exposure and changes in the levels of inflammatory cytokines (IL-1beta, IL-8, IFN-gamma, and TNF-alpha) were quantitated by a multiplexed chemiluminescence-based immunoassay. Rabbit vaginal tissues were evaluated for localized cellular inflammation and in situ apoptosis by immunohistochemical staining for CD45, nuclear factor (NF)-kappa B, and terminal deoxynucleotidyl transferase-mediated FITC-deoxyuridine triphosphate nick-end labeling (TUNEL) using confocal laser scanning microscopy (CLSM), respectively. Vanadium content in selected organs and body fluids from rabbits and pigs was determined by atomic absorption spectroscopy. When compared with 4% N-9 (total irritation score 13-14 out of a possible 16), none of the rabbits given WHI-07 plus VDDTC intravaginally, developed histological alterations such as epithelial erosion, edema, leukocyte influx or vascular congestion characteristic of inflammation (total irritation score 4-6). CD45 and NF-kappa B immunoreactivity was limited to cells within the vascular lumen of both control and WHI-07 plus VDDTC-treated vaginal tissues. TUNEL assay revealed lack of increased apoptotic cells in vaginal mucosa exposed to increasing concentrations of WHI-07 plus VDDTC. Basal levels of proinflammatory cytokines (IL-1beta, IL-8, IFN-gamma and TNF-alpha) in porcine CVL were unaffected by intravaginal exposure to WHI-07 plus VDDTC when compared with BZK used as a positive control. Endpoint histology of the reproductive tract from cats and pigs after a single or repeated intravaginal exposure to WHI-07 plus VDDTC, respectively, revealed lack of irritation/inflammation in the epithelium, subepithelium/lamina propria, vessels/perivascular tissues, and underlying/surrounding muscles. Vanadium was not preferentially incorporated into rabbit or porcine tissues and body fluids at levels above 1 microg/g. Based on comparative histologic data and surrogate markers for inflammation, repeated intravaginal administration of WHI-07 plus VDDTC via a gel-microemulsion did not result in vaginal irritation, mucosal toxicity, or systemic absorption of vanadium. Therefore, the combined use of WHI-07 and VDDTC via gel-microemulsion appears safe for topical use as a prophylactic anti-HIV microbicide.

Vaginal contraceptive activity of a chelated vanadocene

Bis(cyclopentadienyl) complexes of vanadium (IV) or vanadocenes are rapid and potent inhibitors of human sperm motility with potential as a new class of contraceptive agents. This study sought to determine the vaginal contraceptive activity of vanadocene dithiocarbamate (VDDTC), a stable vanadocene (IV)-chelated complex, using the standard rabbit model as well as the domestic pig as a physiologically relevant animal model for contraception. In experiment I, ovulating New Zealand White does in subgroups of eight were artificially inseminated (AI) with semen mixed with VDDTC (0.01-1 mM) or vehicle. In experiment II, ovulating does in subgroups of 18 were AI at 5 and 60 min after intravaginal application of a gel with and without 0.1% VDDTC or 2% nonoxynol-9 (N-9) (Gynol II, Ortho Pharmaceutical, Raritan, NJ), and allowed to complete term pregnancy. In experiment III, seven sexually mature Duroc gilts in standing estrus were AI with and without intravaginal application of 0.1% VDDTC gel microemulsion. Exposure of rabbit semen to VDDTC at the time of artificial insemination resulted in a dose-dependent reduction in fertility. Exposure of semen to 1 mM VDDTC led to complete inhibition of fertility as assessed by the number of embryos (control 49/94 vs. VDDTC-treated 0/117, p<.0001) or the percent embryos (52% vs. 0%, respectively) based on number of embryos to corpora lutea. Intravaginal administration of 0.1% VDDTC gel microemulsion or Gynol II prior to artificial insemination significantly inhibited term pregnancy rates (88% and 62% inhibition, respectively) when compared to control gel alone. Vanadocene dithiocarbamate gel microemulsion provided 80% inhibition of fertility even when insemination was delayed until 60 min after intravaginal application of VDDTC gel microemulsion. Rabbits that delivered litters despite intravaginal exposure of semen to VDDTC via gel microemulsion had healthy offsprings with no apparent perinatal repercussions. In domestic pigs, intravaginal applications of 0.1% VDDTC gel microemulsion prior to artificial insemination led to complete inhibition of fertility as assessed by the number of embryos (control 29/52 vs. VDDTC-treated 0/44, p<.0001) or the percent embryos (56% vs. 0%, respectively) based on the number of embryos to corpora lutea. These results suggest that VDDTC is a potent contraceptive agent in vivo. Intravaginal use of VDDTC via a gel microemulsion has clinical potential as a safe alternative to currently used detergent-type contraceptives.

Inhibition of sperm production in mice by annexin V microinjected into seminiferous tubules: possible etiology of phagocytic clearance of apoptotic spermatogenic cells and male infertility

Many differentiating spermatogenic cells die by apoptosis during the process of mammalian spermatogenesis. However, very few apoptotic spermatogenic cells are detected by histological examination of the testis, probably due to the rapid elimination of dying cells by phagocytosis. Previous in vitro studies showed that Sertoli cells selectively phagocytose dying spermatogenic cells by recognizing the membrane phospholipid phosphatidylserine (PS), which is exposed to the surface of spermatogenic cells during apoptosis. We examined here whether PS-mediated phagocytosis of apoptotic spermatogenic cells occurs in vivo. For this purpose, the PS-binding protein annexin V was microinjected into the seminiferous tubules of normal live mice, and their testes were examined. The injection of annexin V caused no histological changes in the testis, but significantly increased the number of apoptotic spermatogenic cells as assessed by the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay. The number of Sertoli cells did not change in the annexin V-injected testes, and annexin V itself did not induce apoptosis in primary cultured spermatogenic cells. These results indicate that annexin V inhibited the phagocytic clearance of apoptotic spermatogenic cells and suggest that PS-mediated phagocytosis of those cells occurs in vivo. Furthermore, the injection of annexin V into the seminiferous tubules brought about a significant reduction in the number of spermatogenic cells and epididymal sperm in anticancer drug-treated mice. This suggests that the elimination of apoptotic spermatogenic cells is required for the production of sperm.

Vanadium in cancer treatment

Vanadium compounds exert preventive effects against chemical carcinogenesis on animals, by modifying, mainly, various xenobiotic enzymes, inhibiting, thus, carcinogen-derived active metabolites. Studies on various cell lines reveal that vanadium exerts its antitumor effects through inhibition of cellular tyrosine phosphatases and/or activation of tyrosine phosphorylases. Both effects activate signal transduction pathways leading either to apoptosis and/or to activation of tumor suppressor genes. Furthermore, vanadium compounds may induce cell-cycle arrest and/or cytotoxic effects through DNA cleavage and fragmentation and plasma membrane lipoperoxidation. Reactive oxygen species generated by Fenton-like reactions and/or during the intracellular reduction of V(V) to V(IV) by, mainly, NADPH, participate to the majority of the vanadium-induced intracellular events. Vanadium may also exert inhibitory effects on cancer cell metastatic potential through modulation of cellular adhesive molecules, and reverse antineoplastic drug resistance. It also possesses low toxicity that, in combination with the synthesis of new, more potent and better tolerated complexes, may establish vanadium as an effective non-platinum, metal antitumor agent.

Subchronic (13-week) toxicity studies of intravaginal administration of spermicidal vanadocene acetylacetonato monotriflate in mice

Bis-cyclopentadienyl complexes of vanadium(IV) or vanadocenes are rapid and potent inhibitors of human sperm motility with potential as a new class of contraceptive agents. In this study, groups of 10 B(6)C(3)F(1) and 20 CD-1 female mice were exposed intravaginally to a gel-microemulsion containing 0, 0.06, 0.12, or 0.25% of a representative vanadocene, vanadocene acetylacetonato monotriflate (VDACAC), five days per week for 13 consecutive weeks. The doses of VDACAC used were nearly 300- to 1250-fold higher than its in vitro spermicidal EC(50) value. After 13 weeks of intravaginal treatment, B(6)C(3)F(1) mice were evaluated for survival, body weight gain, absolute and relative organ weights, and systemic toxicity. Blood was analyzed for hematological and clinical chemistry profiles. Microscopic examination was performed on hematoxylin- and eosin-stained tissue sections from each study animal. Vanadium content in tissues was determined by atomic absorption spectroscopy. Gel-microemulsion (placebo) control and VDACAC dosed female CD-1 mice were mated with untreated males in order to evaluate if VDACAC has any adverse effects on the reproductive outcome. There were no treatment-related mortalities in either study. Mean body weight gain during the dosing period was not reduced by VDACAC treatment. Hemograms or clinical chemistry profiles did not reveal any toxicologically significant changes attributed to VDACAC treatment. No clinically significant dose-dependent changes in absolute and relative organ weights were noted in VDACAC dose groups. Extensive histopathological examination of tissues revealed no treatment-related abnormalities in any of the three VDACAC dose groups. Vanadium was not incorporated in mouse tissues at levels above 1 microg/g. Repeated intravaginal exposure of CD-1 mice to increasing concentrations of VDACAC for 13 weeks had no adverse effect on their subsequent reproductive capability (100% fertile), neonatal survival (>96%) or pup development. Collectively, these findings demonstrate that repetitive intravaginal administration of VDACAC to yield effective spermicidal concentrations (<0.1%) in the vagina was not associated with systemic toxicity and did not adversely affect the reproductive performance in mice. The spermicidal vanadocene-chelated complex, VDACAC, may be useful as a safe vaginal contraceptive.

Subchronic (13-week) toxicity studies of intravaginal administration of spermicidal vanadocene dithiocarbamate in mice

Spermicidal organometallic complexes of vanadium(IV) with bis(cyclopentadienyl) rings or vanadocenes are a new class of experimental contraceptive agents. In a systematic search for vanadocenes with selective spermicidal activity, we identified vanadocene dithiocarbamate (VDDTC) as the most potent and stable spermicidal compound. In this study, groups of 10 B(6)C(3)F(1) and 20 female CD-1 mice were exposed intravaginally to a gel-microemulsion containing 0, 0.06, 0.12, and 0.25% VDDTC 5 days per week for 13 consecutive weeks. The doses of VDDTC used were nearly 1250- to 5000-fold higher than its in vitro spermicidal EC(50) value. After 13 weeks of intravaginal treatment, B(6)C(3)F(1) mice were evaluated for survival, body weight gain, absolute and relative organ weights, and systemic toxicity. Blood was analyzed for hematologic and clinical chemistry parameters. Microscopic examination was performed on hematoxylin and eosin-stained tissue sections from each study animal. Vanadium content in tissues was determined by atomic absorption spectroscopy. Placebo control and VDDTC-dosed female CD-1 mice were mated with untreated males to evaluate whether VDDTC has any deleterious effects on the reproductive performance. There were no treatment-related effects on survival and mean body weight and mean body weight gain during the dosing period. The blood chemistry or hemogram profiles did not reveal any toxicologically significant changes that could be attributed to VDDTC treatment. No clinically significant changes in absolute and relative organ weights were noted in VDDTC dose groups. Extensive histopathological examination of tissues revealed no treatment-related abnormalities in any of the three VDDTC dose groups. The vanadium content of all mouse tissue analyzed was <1 microg/g. Repeated intravaginal exposure of CD-1 mice to increasing concentrations of VDDTC for 13 weeks had no adverse effect on their subsequent reproductive capability (100% fertile), neonatal survival (>90%), or pup development. Collectively, these findings demonstrate that repetitive intravaginal administration of VDDTC to yield effective spermicidal concentrations (<0.1%) in the vagina was not associated with systemic toxicity and did not adversely affect the reproductive performance in mice. VDDTC may have clinical utility as an active ingredient of non-detergent type, safe, vaginal spermicidal contraceptives.

Bis(4,7-dimethyl and 5-dinitro-1,10-phenanthroline) sulfato-oxovanadium(IV)-mediated in vivo male germ cell apoptosis

Oxovanadium(IV) [VO] complexes of 1,10-phenanthroline are a new class of potent apoptosis-inducing cytotoxic agents against human testicular cancer cells in vitro. The present study investigated the in vivo ability of four(bis)-chelated 1,10-phenanthroline [phen] complexes of sulfato-oxovanadium(IV)-VO(phen)(2), VO(Cl-phen)(2), VO(Me(2)-phen)(2) and VO(NO(2)-phen)(2)-with and without substitutions, to induce testicular germ cell apoptosis. Male germ cell loss in mice was measured by determining the epididymal sperm count, testicular weight and histological evaluation of the testes. Repetitive intratesticular injection (7.5 mg kg(-1) testis(-1)) of bis-chelated 1,10-phenanthroline complexes of oxovanadium(IV) with 4,7-dimethyl [VO(Me(2)-phen)(2)] and 5-dinitro [VO(NO(2)-phen)(2)] substitution led to decreased sperm counts and reduced testicular weights. Histopathological examination of testicular sections from VO(Me(2)-phen)(2)- and VO(NO(2)-phen)(2)-treated mice revealed a marked inhibition of spermatogenesis and preferential loss of maturing, as well as elongated spermatids. In situ evaluation of seminiferous tubule cross-sections by terminal deoxynucleotidyl transferase-mediated FITC-deoxyuridine triphosphate nick end-labeling (TUNEL) and laser scanning confocal microscopy showed characteristic apoptotic germ cells delineating the periphery of the seminiferous tubules. The ability of bis-chelated 4,7-dimethyl- and 5-dinitro-substituted 1,10-phenanthroline complexes of oxovanadium(IV) to induce germ cell apoptosis in vivo may have potential utility in the treatment of human testicular germ cell tumors.