ABSTRACT
Due to the massive industrial development during recent decades, the general population today is exposed to numerous environmental chemicals not only through occupational exposure but also through the daily handling and consumption of products. In our study, we developed a carcinogenesis bioassay for industrial solvents and other pollutants by measuring the gliosis produced by these toxins. We investigated the morphological changes produced by some pollutants in astroglial rat cultures and the increase in GFAP-positive cells. Astroglial primary cultures were obtained from the cerebral hemispheres of neonatal rats. The nutrient medium consisted of Waymouth's medium supplemented with 20% fetal calf serum and antibiotics. The cultures were incubated at 37 degrees C in a humidified particle-filtered room containing an atmosphere of 5% CO2 in air. After being cultured for 22 days, toluene and a mixture of solvents (toluene, carbon tetrachloride, and 1,1,1-trichloroethylene) were applied in concentrations between 10(-4) M and 10(-6) M. Immunofluorescence staining for glial fibrillary acidic protein (GFAP), a specific marker for fibrillary astrocytes, was only occasionally positive in the monolayer of the control cultures; however, it was markedly positive in most cells maintained for 3 or 9 days and exposed to toluene and mixed solvents. This study provides a rapid in vitro assay by which cells exposed to chemicals can be examined.
Subject(s)
Biomarkers, Tumor , Glial Fibrillary Acidic Protein/analysis , Neoplasms, Experimental/chemistry , Neoplasms, Experimental/chemically induced , Animals , Animals, Newborn , Astrocytes/chemistry , Astrocytes/drug effects , Astrocytes/pathology , Brain/drug effects , Brain/pathology , Cell Division/drug effects , Cell Line , Cell Transformation, Neoplastic/chemically induced , Cell Transformation, Neoplastic/chemistry , Cell Transformation, Neoplastic/pathology , Models, Biological , Neoplasms, Experimental/pathology , Rats , Rats, Wistar , Solvents/toxicity , Toluene/toxicityABSTRACT
beta-Aminopropionitrile (beta APN), inhibits the activity of lysyl oxidase, an important enzyme for the post-translational formation of inter- and intramolecular covalent cross-linking between the connective tissue proteins, collagen and elastin. We became interested in the possible use of this compound as a therapeutic agent in the so-called human collagen diseases. beta APN's action mechanism is known, but its pharmacokinetics in rabbits have not yet been determined. The present study defined the kinetic parameters of beta APN in rabbits, after oral or intravenous (iv) administration. The HPLC technique was recently modified using OPA (ortho-phthalaldehyde) as the derivative agent. beta APN plasma concentration vs time following the iv administration of 200 mg/kg was best described by the biexponential equation C = 92.43.e(-0.0728 t) + 61.78.e(-0.0088 t) (t1/2 beta = 78.73 +/- 5.19 min; Vc = 1.29 +/- 0.04 L.kg-1). After oral administration, beta APN followed a zero-order absorption pattern (Ko = 3.02 +/- 0.34 mg.kg-1.min-1), which means that the beta APN reached the blood very quickly.
Subject(s)
Aminopropionitrile/pharmacokinetics , Administration, Oral , Aminopropionitrile/administration & dosage , Aminopropionitrile/blood , Animals , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/blood , Enzyme Inhibitors/pharmacokinetics , Half-Life , Injections, Intravenous , Intestinal Absorption , Metabolic Clearance Rate , Protein-Lysine 6-Oxidase/antagonists & inhibitors , RabbitsABSTRACT
beta-Aminopropionitrile (beta APN), a peptide found in leguminous plants, is a multifunctional aminonitrile because it has some action on collagen, elastin, and nervous cells. Due to its action on the nervous system, it is very interesting to show its inhibitory effect on cultures of neurons. In the present study, we have demonstrated that beta APN can produce progressive degeneration of neurons and that this effect is dose-dependant. Neuronal cultures were prepared from 14-day-old rat embryos with a cell density of 10(4) cells/cm2 in the control plates. Progressive concentrations of beta APN (from 10(-7) M to 10(-3) M) were added and a 50 Inhibitory Dose (ID50) of 10(-5) M was found. At concentrations of 10(-5) M of beta APN, the neurons showed a loss of synapsis and thinning of neuronal prolongations. Based on the morphological changes observed, we think that beta APN may be used as a neurodegeneration model similar to that obtained with acrylamide, carbon disulfide, beta-beta'-iminodipropionitrile, or aluminum salts.
Subject(s)
Aminopropionitrile/toxicity , Neurons/drug effects , Analysis of Variance , Animals , Cells, Cultured , Dose-Response Relationship, Drug , Nerve Degeneration/drug effects , Rats , Rats, WistarABSTRACT
Many of the currently prevailing toxicologic problems are due to the use of organic mercurial compounds in pesticides and fungicides. During recent years, environmental pollution has originated from the incorrect use of these organometals. Methyl-mercury (Me-Hg) is absorbed quickly from the gastrointestinal tract and is distributed to most tissues. The most important effect of Me-Hg is on the nervous tissue and is more relevant in the fetal brain. We were interested in assessing the neurotoxic effects of Me-Hg on the central and peripheral nervous system. Neuronal cells cultures from 14-day-old fetal Wistar rats and ciliary ganglion cells cultures from 8-day-old chick embryos were used. Various Me-Hg concentrations (10(-3) M to 10(-8) M) were added to these cultures after 36 hr to study the morphologic changes. At 10(-3) M and 10(-4) M concentrations, cellular degeneration and death in the central nervous system (CNS) were noted. At 10(-5) M concentrations, axonal and nerve fibers degeneration, loss of synapsis, and inhibition in the cellular development in CNS were seen; regroupment and destruction in the peripheral nervous system (PNS) was noted. Finally, at 10(-6) M and 10(-7) M concentrations, there were hardly any modifications in the CNS, whereas only the nervous processes were affected in the PNS.
Subject(s)
Central Nervous System/drug effects , Methylmercury Compounds/toxicity , Peripheral Nervous System/drug effects , Animals , Axons/drug effects , Cell Division/drug effects , Cells, Cultured , Central Nervous System/cytology , Chick Embryo , Nerve Degeneration/drug effects , Nerve Fibers/drug effects , Peripheral Nervous System/cytology , Rats , Rats, Wistar , Synapses/drug effectsABSTRACT
Ethylene glycol (EG) is the most representative of the glycols. It is a compound used as painting and plastic solvent, as antifreeze, and in dyes and synthetic fibers. It may also appear as a wine pollutant. Due to these various uses and conditions, EG can produce intoxication in men and animals. The pathologic effects are due to its metabolism resulting in the formation of oxalic and glycolic acids which are eliminated through the kidney causing renal failure. The toxic effects on the nervous system are not well known. In some circumstances, convulsions may occur. To study the neurotoxic effects of EG, we used cultures of nerve cells from Wistar rat embryos which we exposed to EG in doses between 10(-4) M and 10(-8) M. The changes in neurons consisted of neuronal degeneration, decrease in number of AChE+ cells, and reactive cellular grouping. The median inhibitory concentration (IC50) was 2.06 x 10(-7) M.
