Enhancement of maternal and fetal nephrotoxicity of salicylate by zinc deficiency. Morphological, enzyme histochemical and immunohistochemical studies

Zinc deficient diet increases the toxicity of bisphenol A in rat testis

Zinc (Zn) plays an important role in maintaining the process of spermatogenesis and reproductive health. Bisphenol A (BPA), an endocrine disrupting chemical is known to be a reproductive toxicant in different animal models. The present study was designed to study the effect of two of the utmost determinative factors (Zn deficient condition and influence of toxicant BPA) on germ cell growth and overall male reproductive health in the testis, epididymis, and sperm using (a) biochemical, (b) antioxidant, (c) cellular damage, (d) apoptosis, and (e) protein expression measurements. Rats were divided into Control (normal feed and water), BPA (100 mg/kg/d), zinc deficient diet (ZDD; fed with ZDD), and BPA + ZDD for 8 weeks. Body and organ weights, sperm motility and counts, and sperm head morphology were evaluated. The histology of testes, epididymides, and prostate was investigated. Testicular deoxyribonucleic acid (DNA) damage was evaluated by Halo and Comet assay, apoptosis of sperm and testes were quantified by TUNEL assay. Serum protein electrophoretic patterns and testicular protein expressions such as Nrf-2, catalase, PCNA, and Keap1 were analyzed by Western blot analysis. The results showed that BPA significantly increased the testicular, epididymal, and prostrate toxicity in dietary Zn deficient condition due to testicular hypozincemia, hypogonadism, increased cellular and DNA damage, apoptosis, as well as perturbations in protein expression.

Histochemical response of mice to mistletoe lectin I (ML I)

The acute toxicity of lectin ML I from the toxic drug, mistletoe, was demonstrated in previous experiments. Because the reason for this extremely high toxicity is not yet clear, mice were studied histochemically at different times after treatment with various doses of ML I, ML I A or ML I B chain separately, or recombinations of ML I A and ML I B. Various plasma membrane-associated hydrolases as well as Golgi apparatus-and endoplasmic reticulum-linked hydrolases, peroxisomal and extraperoxisomal oxidases, lysosomal hydrolases, mitochondrial dehydrogenases, the cytoskeletal proteins keratin and vimentin as well as iron, glycogen and lipids were analysed in all organs and tissues of female mice. Irrespective of the dose, a clear-cut response was only observed in the liver. After ML I treatment, glycogen disappeared completely from all hepatocytes, and this effect did not depend on the ML I-concentration and exposure time. The increase in activity of Golgi-associated thiamine pyrophosphatase in hepatocytes and of non-specific alkaline phosphatase in the sinusoidal endothelial cells depended on the applied ML I concentration and the time of treatment. Doses of 600 or 900 ng ML I/kg drastically increased the phosphatase activities. These clear-cut changes of glycogen and enzyme activities were not observed after administration of the ML I B chain alone, and less so when the mice were treated only with the ML I A chain, or were treated with a recombination of ML I A and ML I B even at concentrations higher than that of ML I.(ABSTRACT TRUNCATED AT 250 WORDS)

Menadiol diphosphate, a new substrate for non-specific alkaline phosphatase in histochemistry and immunohistochemistry

Menadiol diphosphate was introduced as a new substrate for nonspecific alkaline phosphatase, following a search for new and less expensive substrates, which give a more sensitive response and are easily synthesized in the laboratory. Menadiol released by phosphatase action can be assayed by its reduction of tetrazolium salts, or it can be coupled with diazonium salts; alternatively, the phosphate can be trapped by metal ions. The synthesis and purification of menadiol diphosphate are described, and it was shown to be sufficiently stable for qualitative and semiquantitative histochemistry, as well as for the immunohistochemistry of enzymes and cytoskeletal proteins with nonspecific alkaline phosphatase as the enzyme label. For qualitative as well as semiquantitative histochemistry and immunohistochemistry, the best results were obtained by applying the method with nitro-blue tetrazolium (NBT) to acetone-chloroform pretreated cryostat sections. Tetranitro-blue tetrazolium (TNBT), benzothiazolylphthalhydrazidyl tetrazolium (BSPT) and various diazonium salts were less suitable. Fast Blue BB and VB produced satisfactory results. Ce3+ ions and the DAB-Ni-H2O2 procedure yielded better results than Ca2+ ions in the Co-(NH4)2S visualization method. The NBT method with menadiol diphosphate is superior to existing methods employing azo, azoindoxyl or tetrazolium salts and to metal precipitation methods. The Ce3+ technique and the NBT/menadiol diphosphate method give similar results, and appear to be of equal value. In qualitative histochemistry and immunohistochemistry the NBT/menadiol diphosphate method resulted in higher quantities of precisely localized stain. Semiquantitative histochemistry with minimal incubation revealed more favorable kinetics for the menadiol diphosphate method, especially when using NBT.

Lipid peroxidation in mitochondria and microsomes from adult and fetal rat tissues. Effects of Zn deficiency, Fe, and salicylate

Pregnant female Wistar rats that received a control (100 ppm Zn) or a Zn-deficient diet (1.5 ppm Zn) from d 0 to 21, or nonpregnant normally fed female rats without or with five daily oral doses of 300 mg/kg salicylic acid were used for the experiments. In isolated mitochondria or microsomes from various maternal and fetal tissues, lipid peroxidation was determined as malondialdehyde formation measured by means of the thiobarbiturate method. Zn deficiency increased lipid peroxidation in mitochondria and microsomes from maternal and fetal liver, maternal kidney, maternal lung microsomes, and fetal lung mitochondria. Lipid peroxidation in fetal microsomes was very low. Zn deficiency produced a further reduction of lipid peroxidation in fetal liver microsomes. Salicylate increased lipid peroxidation in liver mitochondria and microsomes after addition in vitro and after application in vivo. The increase of lipid peroxidation by salicylate may be caused by two mechanisms: an increased cellular Fe uptake that, in turn, can increase lipid peroxidation and chelating Fe, in analogy to the effect of ADP in lipid peroxidation. The latter effect of salicylate is particularly expressed at increased Fe content.

Enhanced light microscopic visualization of oxidase activity with the cerium capture method

Visualization methods for the light microscopic detection of the activity of oxidases after being localized with cerium ions as reported by Angermüller and Fahimi (1988a, b) are not suitable for the demonstration of H2O2-genrating oxidases at sites with low activity. Therefore, the cerium-diaminobenzidine (DAB) visualization procedure of these authors was modified. Nickel or cobalt ions were added to the DAB solution together with small amounts of H2O2. Visualization was performed in a one-step-method. This modified visualization technique enables light microscopic detection of amino acid oxidase activity in kidney and liver cells where it was found with the original method but the amounts of final reaction product were considerably higher. Moreover, the DAB-nickel-H2O2 and DAB-cobalt-H2O2 procedures were more sensitive than the cerium-lead method of Angermüller and Fahimi (1988a, b). The method appeared to be specific, because final reaction product was not found after control incubation. Especially the DAB-nickel-H2O2 procedure can also be used for immunohistochemistry when glucose oxidase serves as the enzyme label.

Enhancement of gentamicin-induced nephrotoxicity by Mg deficiency in non-pregnant rats. Morphological, enzyme histochemical and immunohistochemical studies

Non-pregnant rats fed an Mg-deficient diet showed some degenerated and calcified proximal tubules in the inner region of the medullary rays accompanied by reduced or absent enzyme activities. After gentamicin treatment some damaged convoluted proximal tubules occurred. Enzyme histochemistry revealed decreased activities for brush border and lysosomal hydrolases; using immunohistochemistry lesions were detectable for the cytoskeletal proteins keratin and vimentin. Administration of gentamicin to Mg-deficient rats led to a further decrease of hydrolase activities in obviously intact proximal tubules and drastic structural and enzymatic defects as well as alterations of the cytoskeletal proteins in the convoluted and straight segments of other proximal tubules and to a lesser degree also in glomeruli and further portions of the tubular apparatus including the collecting ducts.

Maternal and fetal iron accumulation in Zn-deficient and salicylate-treated rats

Nonhemoglobin Fe (non Hb-Fe) content in fetal serum and liver is much higher than in maternal serum and liver. After feeding a Zn-deficient diet to pregnant rats from d 0 to 21, non Hb-Fe content in maternal and fetal serum and liver was increased. After oral application of salicylic acid (300 mg/kg) from d 16 to 20 to normally fed and Zn-deficient dams, non Hb-Fe content in maternal and particularly in fetal serum and liver was drastically increased. In the kidney, Fe was accumulated to a small amount resulting from Zn deficiency and salicylate treatment. Fe accumulation in the liver occurred in all cell fractions, particularly in microsomes. Fe accumulation was confirmed and extended histochemically by Prussian blue staining. It is assumed that salicylate increases intestinal Fe resorption and fetal transfer of Fe. It is discussed that salicylate nephrotoxicity and its enhancement by Zn deficiency is not caused by an Fe-dependent mechanism.

The cerium perhydroxide-diaminobenzidine (Ce-H2O2-DAB) procedure. New methods for light microscopic phosphatase histochemistry and immunohistochemistry

New light microscopic visualization methods were developed for the histochemical detection of non-specific alkaline and acid phosphatase, Mg-, Ca- and Na, K-dependent adenosine triphosphatase, myosin adenosine triphosphatase, glucose-6-phosphatase, 5'-nucleotidase and thiamine pyrophosphatase with cerium ions as trapping agents in cryostat and plastic sections. The techniques are based on the conversion of cerium phosphate into cerium perhydroxide by H2O2 which decomposes at 55 degrees-60 degrees C into cerium hydroxide and oxygen radicals. These radicals are able to oxidize diaminobenzidine (DAB) to DAB brown. Addition of nickel ions to the DAB-H2O2 mixture generates bluish-black stained nickel-DAB complexes. Compared with the classical metal precipitation, azo, azoindoxyl and tetrazolium procedures the H2O2-DAB and especially the H2O2-DAB-nickel methods provided identical or superior results in catalytic phosphatase histochemistry and immunohistochemistry when using non-specific alkaline phosphatase as the enzyme label.