OBJECTIVETo study the mechanism of male reproductive toxicity of metadoxine (MTDX) on mice and rats.

METHODSMouse multiple endpoints assay and Hershberger assay were employed to evaluate the potential estrogenic and/or antiandrogenic effects of MTDX. In mouse multiple endpoints assay, MTDX (0, 640, 1500 and 4000 mg/kg, respectively) were administered once daily p.o. for 5 days in sexually matured and ovariectomied female NIH mice. Five endpoints evaluated as markers of estrogenicity included the ratio of uterine weight to body weight, incidence and extent of uterine fluid imbibition (hydrometra), vaginal epithelial cornification during estrous cycle (estrinization) and thickness of uterine epithelial cell and stroma cell. In Hershberger assay, MTDX (0, 600 and 1500 mg/kg, respectively) was administered once daily p.o. for 10 days to castrated male SD rats with or without testosterone propionate (TP, 12.5 mg/kg, i.p. for 10 days) substitution. Relative weight of androgen dependent issues was measured.

RESULTSIn mouse multiple endpoints assay, ratio of uterine weight to body weight was 1.33, 1.38 and 1.31 x 10(-4) in MTDX 640, 1500 and 4000 mg/kg groups, respectively, without significant difference from that in control group (1.22 x 10(-4)). Thickness of uterine uterine epithelial cell (0.90 and 1.03 microm) and stroma cell (3.38 and 3.25 microm) in MTDX 1500 and 4000 mg/kg groups was not significantly different from the control group (0.85 microm and 2.77 microm, respectively). In Hershberger assay, relative weight of prostate plus seminal vesicle, levator ani muscle and bulbocavernous muscle was 1.13, 0.17 and 0.42, respectively, in the 1500 mg/kg group, significantly decreased as compared with those in the control group (1.46, 0.24 and 0.70, respectively) (P < 0.01). Relative weight of prostate plus seminal vesicle (1.29) in the MTDX 600 mg/kg group reduced slightly, with statistical significance (P < 0.05), as compared with that in the control group (1.46).

CONCLUSIONSIn the present study, MTDX did not exhibit any estrogenic effect in mice in vivo. However, it had antiandrogenic activity in castrated male SD rats, indicating that its antiandrogenic effect may be involved in it's male reproductive toxicity.

Androgen Antagonists ; toxicity ; Animals ; Drug Combinations ; Endpoint Determination ; Female ; Genitalia, Male ; drug effects ; pathology ; Male ; Mice ; Orchiectomy ; Ovariectomy ; Pyridoxine ; toxicity ; Pyrrolidonecarboxylic Acid ; toxicity ; Rats

To construct a sensory neuropathy model, excess pyridoxine (150 mg/kg s.i.d.) was injected subcutaneously in dogs over a period of 7 days. During the administrations period, the dogs experienced body weight reduction and proprioceptive loss involving the hindquarters. After pyridoxine administration was completed, electrophysiological recordings showed that the M wave remained at a normal state, but the H-reflex of the treated dogs disappeared at 7 days. The dorsal funiculus of L4 was disrupted irregularly in the axons and myelin with vacuolation. The dorsal root ganglia of L4, and sciatic and tibial nerves showed degenerative changes and vacuolation. However, the lateral and ventral funiculi of L4 showed a normal histopathologic pattern. Although this subcutaneous administration method did not cause systemic toxicity and effectively induced sensory neuropathy, this study confirmed the possibility of producing a pyridoxine-induced sensory neuropathy model in dogs with short-term administration.
Animals ; Body Weight/drug effects ; *Disease Models, Animal ; Dogs ; Electrophysiology ; Neurodegenerative Diseases/*chemically induced/pathology ; Proprioception/drug effects ; Pyridoxine/*toxicity

OBJECTIVETo study the reproductive toxicity of metadoxine.

METHODSMale and female rats were given metadoxine before pregnancy and early gestation, i.e. to feed metadoxine to male rats for 60 days before copulation and continue feeding during copulation, and feed metadoxine to female rats for 14 days before copulation.

RESULTSNo significant toxic effect was observed in the 400 mg/kg group. A few rats showed paralysis of hind leg in the 800 mg/kg group. The dosage of 1 600 mg/kg caused significant paralysis of hind legs, emaciation, and reduced weight gain. In the 1600 mg/kg group, the mating rate of male rats was significantly affected (P < 0.01). In the 800 and 1 600 mg/kg group, fertility of male rats was markedly reduced (P < 0.01). In the 800 mg/kg group, the effect on sperm counts of epididymis of male rats was markedly reduced (P < 0.05). In the 1 600 mg/kg group, testicle weight and body weight ratio and sperm counts of epididymis rate were significantly (P < 0.001) reduced. In the 1 600 mg/kg group, the fertility rate of female rats was remarkably (P < 0.001) reduced. In the 800 mg/kg group, the weight gain of pregnant rats was significantly reduced (P < 0.001). In both the 800 and 1 600 mg/kg groups, the gestation rate was greatly reduced (P < 0.001). In the 800 mg/kg group, mortality rate before nidation (P < 0.001) and average live fetus number were significantly reduced (P < 0.05). In the 400 mg/kg group, the fetal weight was significantly reduced (P < 0.001). In the 800 mg/kg group, body length, tail length, body weight and sternum development of fetal rats were significantly affected (P < 0.001).

CONCLUSIONUnder the presented experimental conditions, metadoxine has no teratogenic effects on SD rats and the no effect dose is 400 mg/kg. And the no effect dose for the developmental toxicity is less than 400 mg/kg.

Animals ; Dose-Response Relationship, Drug ; Drug Combinations ; Female ; Fertility ; drug effects ; Fetal Weight ; Male ; Organ Size ; Pregnancy ; Pyridoxine ; toxicity ; Pyrrolidonecarboxylic Acid ; toxicity ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sperm Count ; Testis ; anatomy & histology

Due to the therapeutic potential of gene therapy for neuronal injury, many studies of neurotrophic factors, vectors, and animal models have been performed. The presumed dog beta-nerve growth factor (pdbeta-NGF) was generated and cloned and its expression was confirmed in CHO cells. The recombinant pdbeta-NGF protein reacted with a human beta-NGF antibody and showed bioactivity in PC12 cells. The pdbeta-NGF was shown to have similar bioactivity to the dog beta-NGF. The recombinant pdbeta-NGF plasmid was administrated into the intrathecal space in the gene therapy group. Twenty-four hours after the vector inoculation, the gene therapy group and the positive control group were intoxicated with excess pyridoxine for seven days. Each morning throughout the test period, the dogs' body weight was taken and postural reaction assessments were made. Electrophysiological recordings were performed twice, once before the experiment and once after the test period. After the experimental period, histological analysis was performed. Dogs in the gene therapy group had no weight change and were normal in postural reaction assessments. Electrophysiological recordings were also normal for the gene therapy group. Histological analysis showed that neither the axons nor the myelin of the dorsal funiculus of L(4) were severely damaged in the gene therapy group. In addition, the dorsal root ganglia of L(4) and the peripheral nerves (sciatic nerve) did not experience severe degenerative changes in the gene therapy group. This study is the first to show the protective effect of NGF gene therapy in a dog model.
Amino Acid Sequence ; Animals ; Base Sequence ; CHO Cells ; Central Nervous System Diseases/chemically induced/therapy/*veterinary ; Cloning, Molecular ; Cricetinae ; Cricetulus ; Cytomegalovirus ; Dog Diseases/*chemically induced/therapy ; Dogs ; Female ; Gene Therapy/*veterinary ; Genetic Vectors ; Male ; Molecular Sequence Data ; Nerve Growth Factor/genetics/*metabolism/*therapeutic use ; Pyridoxine/*toxicity

Animals ; Body Weight ; physiology ; Computational Biology ; methods ; Disease Models, Animal ; Doxorubicin ; toxicity ; Fatty Acids, Monounsaturated ; blood ; metabolism ; Glomerulosclerosis, Focal Segmental ; blood ; chemically induced ; metabolism ; Male ; Methoxyhydroxyphenylglycol ; analogs & derivatives ; blood ; metabolism ; Mice ; Mice, Inbred BALB C ; Pyridoxine ; blood ; metabolism ; Valine ; analogs & derivatives ; blood ; metabolism ; Vanillic Acid ; blood ; metabolism