Assessment of hematological, hepato-renal, antioxidant, and hormonal responses of Clarias gariepinus exposed to sub-lethal concentrations of oxyfluorfen

Little is known about the effects of oxyfluorfen, a diphenyl ether herbicide, exposure on the African catfish (Clarias gariepinus) health. Consequently, the existing investigation was designed to highlight the impacts of oxyfluorfen exposure on C. gariepinus hematological indices, liver and kidney functions, reproductive hormones, and oxidative status. Furthermore, a consequent 10-day depuration period was adopted to evaluate the recovery of the disturbed indicators to normal values. In the first experiment, the 96-h lethal concentration 50 (LC₅₀) of oxyfluorfen for C. gariepinus was determined using probit analysis. Next, in a second experiment, 180 healthy fish (average initial body weight: 164.23 ± 0.24) were randomly assigned to 4 experimental groups exposed to 0, 1/10, 1/8, or 1/5 96-h LC₅₀ of oxyfluorfen. The hematological profile, hepatic enzymes, kidney damage byproducts, reproductive hormones, oxidative stress, and lipid peroxidation indicators together with acetylcholinesterase (AChE) content were assessed. A histopathological examination of the hepatic, renal, brain, and testicular tissues was accomplished. Moreover, the expression of the oxidative stress-related gene was carried out. The results showed that 96-h LC₅₀ of oxyfluorfen for C. gariepinus was 11.698 mg/L. Exposure to sublethal levels of oxyfluorfen induced macrocytic hypochromic anemia, leukopenia, lymphopenia, monocytopenia, and eosinopenia. Also, a concentration-dependent increase in alanine transaminase, alkaline phosphatase, aspartate transaminase, urea, creatinine, catalase, and malondialdehyde was detected following oxyfluorfen exposure together with upregulation of catalase gene. But, significant concentration-dependent reductions in AChE, glutathione transferase, reduced to oxidized glutathione ratio, estradiol, and testosterone activities were recorded. These biochemical alterations were accompanied by pathological perturbations in hepatic, renal, brain, and testicular tissues. Following 10 days of recovery, only the hematological impairments were abolished. Conclusively, the herbicides oxyfluorfen could induce multiple negative impacts on C. gariepinus with oxidative stress as a probable underlying mechanism. Additionally, a recovery period of 10 days was not enough to restore these impairments.

Oxadiazon affects the expression and activity of aldehyde dehydrogenase and acylphosphatase in human striatal precursor cells: A possible role in neurotoxicity

Exposure to herbicides can induce long-term chronic adverse effects such as respiratory diseases, malignancies and neurodegenerative diseases. Oxadiazon, a pre-emergence or early post-emergence herbicide, despite its low acute toxicity, may induce liver cancer and may exert adverse effects on reproductive and on endocrine functions. Unlike other herbicides, there are no indications on neurotoxicity associated with long-term exposure to oxadiazon. Therefore, we have analyzed in primary neuronal precursor cells isolated from human striatal primordium the effects of non-cytotoxic doses of oxadiazon on neuronal cell differentiation and migration, and on the expression and activity of the mitochondrial aldehyde dehydrogenase 2 (ALDH2) and of the acylphosphatase (ACYP). ALDH2 activity protects neurons against neurotoxicity induced by toxic aldehydes during oxidative stress and plays a role in neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease. ACYP is involved in ion transport, cell differentiation, programmed cell death and cancer, and increased levels of ACYP have been revealed in fibroblasts from patients affected by Alzheimer's disease. In this study we demonstrated that non-cytotoxic doses of oxadiazon were able to inhibit neuronal striatal cell migration and FGF2- and BDNF-dependent differentiation towards neuronal phenotype, and to inhibit the expression and activity of ALDH2 and to increase the expression and activity of ACYP2. In addition, we have provided evidence that in human primary neuronal precursor striatal cells the inhibitory effects of oxadiazon on cell migration and differentiation towards neuronal phenotype were achieved through modulation of ACYP2. Taken together, our findings reveal for the first time that oxadiazon could exert neurotoxic effects by impairing differentiative capabilities of primary neuronal cells and indicate that ALDH2 and ACYP2 are relevant molecular targets for the neurotoxic effects of oxadiazon, suggesting a potential role of this herbicide in the onset of neurodegenerative diseases.

Binding, electrochemical activation, and cleavage of DNA by cobalt(II) tetrakis-N-methylpyridyl porphyrin and its beta-pyrrole brominated derivative

The binding of nucleic acids by water-soluble cobalt(II) tetrakis-N-methylpyridyl porphyrin, (TMPyP)Co, and its highly electron-deficient derivative cobalt(II) tetrakis-N-methyl pyridyl-beta-octabromoporphyrin, (Br(8)TMPyP)Co, was investigated by UV-visible absorption, circular dichroism (CD), and electrochemical and gel electrophoresis methods. The changes of the absorption spectra during the titration of these complexes with polynucleotides revealed a shift in the absorption maxima and a hypochromicity of the porphyrin Soret bands. The intrinsic binding constants were found to be in the range of 10(5)-10(6) M(-1). These values were higher for the more electron-deficient (Br(8)TMPyP)Co. Induced CD bands were noticed in the Soret region of the complexes due to the interaction of these complexes with different polynucleotides, and an analysis of the CD spectra supported a mainly external mode of binding. Electrochemical studies revealed the cleavage of polynucleotides by (TMPyP)Co and (Br(8)TMPyP)Co in the presence of oxygen preferentially at the A-T base pair region. Gel electrophoresis experiments further supported the cleavage of nucleic acids. The results indicate that the beta-pyrrole brominated porphyrin, (Br(8)TMPyP)Co, binds strongly and cleaves nucleic acids efficiently as compared with (TMPyP)Co. This electrolytic procedure offers a unique tool in biotechnology for cleaving double-stranded DNA with specificity at the A-T regions.

The porphyrin pathway: the final common pathway?

When I was learning pathology a wise and knowledgeable mentor described a final common pathway that allows many diseases to overlap in their presentation. This pathway was never identified for it was unknown. Recent books by physicians have suggested that maintaining body balance and/or treatment by a substance could halt or repair damage caused by a wide array of diseases, once again suggesting a common thread amongst diseases. Again no mention was made regarding what was this common denominator. I have been interested in people who have more than one disease, feeling that there must be a link. My interest in the porphyrin pathway has strengthened that impression. Since finding Doss's list of diseases having porphyrin abnormalities unrelated to a porphyria, I have worked on models that would allow me to show a way where porphyrin abnormalities may be a part of the final common pathway for all disease. I have finally decided that a spider's web is that model. The following discussion will attempt to demonstrate that this hypothesis could be true.

Liver preneoplastic changes in mice treated with the herbicide fomesafen

1. Effect of the diphenyl ether herbicide fomesafen on liver preneoplastic changes and porphyrin biosynthesis was examined in male C57BL/6J mice (0.23% in the diet for 14 months) and ICR mice (0.3% in the diet for 50 weeks). Fomesafen treatment resulted in preneoplastic changes (liver nodules and foci of altered hepatocytes) in both strains, uroporphyria developed only in ICR mice. 2. Iron pretreatment (600 mg/kg as a single dose) accelerated the development of fomesafen-induced preneoplastic changes in both mouse strains. The number of foci containing altered hepatocytes, as well as the number and size of liver nodules, were increased in iron-pretreated animals. 3. A single injection of iron induced marked uroporphyria in C57BL/6J mice after 14 months (liver porphyrin content 102 nmol/g). This uroporphyria was further potentiated by fomesafen administration (208 nmol/g). 4. In ICR mice, liver histology was apparently normal after a 3 month recovery from fomesafen treatment (0.32% for 9 months). Liver porphyrin content (260 nmol/g) started to decrease immediately after fomesafen withdrawal, but was still significantly elevated after 3 months (5 nmol/g), as compared to controls (1 nmol/g). 5. It is concluded that the toxicological evaluation of fomesafen should focus on liver porphyrin biosynthesis.