Oral feeding and nasal instillation immunization with Microtus brandti lactate dehydrogenase c epitope DNA vaccine reduces fertility in mice via specific antibody responses

The immune responses induced by Microtus brandti lactate dehydrogenase C4 DNA vaccine via oral feeding and nasal instillation in mouse were investigated. The number of newborns of the vaccinated mice was statistically significantly reduced compared with the control mice, but the vaccine failed to affect the birthrate, as all vaccinated mice gave birth.

Residual oil fly ash inhalation in guinea pigs: influence of absorbate and glutathione depletion

Inhaled urban particulate matter (PM) often contains metals that appear to contribute to its toxicity. These particles first make contact with a thin layer of epithelial lining fluid in the respiratory tract. Antioxidants present in this fluid and in cells might be important susceptibility factors in PM toxicity. We investigated the role of ascorbic acid (C) and glutathione (GSH) as determinants of susceptibility to inhaled residual oil fly ash (ROFA) in guinea pigs (male, Hartley). Guinea pigs were divided into four groups, +C+GSH, +C-GSH, -C+GSH, and -C-GSH, and exposed to clean air or ROFA (< 2.5 micron diameter, 19--25 mg/m(3) nose-only for 2.0 h). C and/or GSH were lowered by either feeding C-depleted diet (1 microg C/kg diet, 2 weeks) and/or by ip injection of a mixture of buthionine-S,R-sulfoximine (2.7 mmol/kg body weight) and diethylmaleate (1.2 mmol/kg, 2 h prior). Nasal lavage (NL) and bronchoalveolar lavage (BAL) fluid and cells were examined at 0 h and 24 h postexposure to ROFA. The C-deficient diet lowered C concentrations in BAL fluid and cells and in NL fluid by 90%, and the GSH-depletion regimen lowered both GSH and C in the BAL fluid and cells by 50%. ROFA deposition was calculated at time 0 from lung Ni levels to be 46 microg/g wet lung. In unexposed animals, the combined deficiency of C and GSH modified the cellular composition of cells recovered in lavage fluid, i.e., the increased number of eosinophils and macrophages in BAL fluid. ROFA inhalation increased lung injury in the -C-GSH group only (evidenced by increased BAL protein, LDH and neutrophils, and decreased BAL macrophages). ROFA exposure decreased C in BAL and NL at 0 h, and increased BAL C and GSH (2- to 4-fold above normal) at 24 h in nondepleted guinea pigs, but had no effect on C and GSH in depleted guinea pigs. Combined deficiency of C and GSH resulted in the highest macrophage and eosinophil counts of any group. GSH depletion was associated with increased BAL protein and LDH, increased numbers of BAL macrophages and eosinophils, and decreased rectal body temperatures. We conclude that combined deficiency of C and GSH increased susceptibility to inhaled ROFA; caused unusual BAL cellular changes; resulted in lower antioxidant concentrations in BAL than were observed with single deficiencies. Antioxidant deficiency may explain increased susceptibility to PM in elderly or diseased populations and may have important implications for extrapolating animal toxicity data to humans.

Osteoarthrosis of the temporomandibular joint induced by intra-articular injection of lactate dehydrogenase: an experimental study in adult rabbits

OBJECTIVE

The purpose of this study was to establish an animal model of osteoarthrosis in the temporomandibular joint (TMJOA) by injecting lactate dehydrogenase (LDH) into the maxillary compartments of TMJs in adult rabbits.

METHODS

Adult New Zealand white rabbits were randomly divided into four groups (A through D) of five animals each. The A and B groups were used as a control. The maxillary compartments of the C and D group (TMJs) were injected with 0.1 mL of LDH in two different concentrations. The TMJ samples were analyzed histologically and with a scanning electron microscope four different times after injection.

RESULTS

The animals that had been injected with LDH at two different concentrations showed similar results. The TMJs had changes typical of OA in early to moderate stages. No pathologic changes could be found in the TMJs of the control groups.

CONCLUSIONS

The results suggest that LDH may be of use in establishing an animal model of TMJOA.

Enzyme polymorphism and function during embryonic development

Alterations in multiple molecular forms of enzymes have been described during normal embryogenesis. Changes in electrophoretic patterns, which differ from the normal isozyme ontogeny, occur in embryos and their yolk-sacs during incipient maldevelopment secondary to teratogen exposure. One such isozyme change, in response to a teratogenic regimen using 9-methyl pteroylglutamic acid (PGA), is persistence of lactate dehydrogenase-5 (LDH-5) beyond its time of normal involution in the rat yolk-sac. Since LDH-5 is an allosteric regulatory enzyme which favors anaerobic metabolism, the cellular respiration of 9-methyl PGA-treated embryos was investigated and found to be depressed. However, no changes were found in the oxidative metabolism of visceral yolk-sacs from similarly treated pregnancies. A possible explanation for the unchanged oxygen consumption is the observed simultaneous quantitative alterations in other LDH-yolk-sac isozymes following 9-methyl PGA treatment. Other potential causes include known changes in isozymes other than LDH, limitation of enzyme function by its substrate or co-factor or the presence of a functionally inert LDH-5 isozyme. Changes in LDH and other isozyme patterns and their associated metabolic alterations may eventually prove useful in predicting chemical teratogenicity.