Exploration of the neurotoxicity of ciprofloxcin or gatifloxacin single dose in rat cortex and hippocampus

Effects of two kinds of fishery drugs on the expressions of GAD and GABA-T mRNA in crucian carp (Carassius auratus gibelio)

The objective of this study was to investigate the effects of difloxacin (DIF) and avermectin (AVM) on glutamate decarboxylase (GAD) and GABA-transaminase (GABA-T) in different tissues of crucian carp (Carassius auratus gibelio). After the treatments of DIF and AVM, the mRNA expressions of GAD and GABA-T in different tissues were detected by quantitative real-time PCR (qPCR). The results showed that the mRNA expressions of GAD₆₅, GAD₆₇, and GABA-T in the telencephalon (Tel), mesencephalon (Mes), cerebella (Cer), and medulla oblongata (Med) were downregulated significantly with the safe dose (SD, 20 mg/kg) of DIF (P < 0.05 or P < 0.01). While the expressions of GAD₆₅ and GAD₆₇ in the kidney at 12 h had strikingly upregulated to 13.81 ± 1.06** and 150.67 ± 12.85** times. Treated with the lethal dose of 50% (LD₅₀, 2840 mg/kg b. W.) of DIF, the mRNA expressions of GAD₆₅, GAD₆₇, and GABA-T in all tissues were increased significantly (P < 0.01). The results of AVM group showed that the mRNA expressions of GAD₆₅, GAD₆₇, and GABA-T both in the central and peripheral tissues were all remarkably downregulated at the safe concentration (SC, 0.0039 mg/L) and the lethal concentration of 50% (LC₅₀, 0.039 mg/L), except for the mRNA inhibitions of GAD₆₅, GAD₆₇, and GABA-T in the muscle at 2 h which sharply downregulated to 0.20 ± 0.02^ΔΔ × 10^-2, 0.57 ± 0.06^ΔΔ × 10^-1 and 0.44 ± 0.02^ΔΔ × 10^-1, respectively (P < 0.01).

MALDI MSI and LC-MS/MS: Towards preclinical determination of the neurotoxic potential of fluoroquinolones

Fluoroquinolones are broad-spectrum antibiotics with efficacy against a wide range of pathogenic microbes associated with respiratory and meningeal infections. The potential toxicity of this class of chemical agents is a source of major concern and is becoming a global issue. The aim of this study was to develop a method for the brain distribution and the pharmacokinetic profile of gatifloxacin in healthy Sprague-Dawley rats, via Multicenter matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) and quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS). We developed a sensitive LC-MS/MS method to quantify gatifloxacin in plasma, lung, and brain homogenates. A pharmacokinetic profile was observed where there is a double peak pattern; a sharp initial increase in the concentration soon after dosing followed by a steady decline until another increase in concentration after a longer period post dosing in all three biological samples was observed. The imaging results showed the drug gradually entering the brain via the blood brain barrier and into the cortical regions from 15 to 240 min post dose. As time elapses, the drug leaves the brain following the same path as it followed on its entry and finally concentrates at the cortex. Copyright © 2015 John Wiley & Sons, Ltd.