The chemoprotective effects of l-carnitine against genotoxicity induced by diazinon in rat blood lymphocyte

The purpose of this study was to assess the preventive effects of l-carnitine (LC) against DNA damage induced by diazinon (DZN) in rat blood lymphocytes. Animals were concurrently administered intraperitoneally with DZN in proper solvent (20 mg/kg body weight (b.w.)) and LC at three different doses (50, 100, and 150 mg/kg b.w.) for 30 consecutive days. The positive control group received DZN at the same dose without LC. Twenty-four hour after last injection, 0.5 ml blood of each rat was received and cultured in culture medium for 44 h. The lymphocyte cultures were mitogenically stimulated with cytochalasin B for the evaluation of the number of micronuclei (MNs) in cytokinesis-blocked binucleated cells. Incubation of lymphocytes with DZN induced additional genotoxicity and was shown by increase in MNs frequency in rat lymphocytes. LC at all doses had a protective effect and significantly reduced the MNs frequency in cultured lymphocytes ( p < 0.0001– p < 0.05). The maximum effect was observed at 150 mg/kg that reduced the frequency of MN from 12.78 ± 0.24% for DZN group to 5.61 ± 0.17%. Our study revealed that LC has a potent antigenotoxic effect against DZN-induced toxicity in rats, which may be due to the scavenging of free radicals and increased antioxidant status. Since LC is a natural compound and is being safe, it is recommended as a daily supplement for body defense against side effects induced by chemical hazardous agents.

Potential chemoprotective effects of selenium on diazinon-induced DNA damage in rat peripheral blood lymphocyte

The purpose of this study was to investigate the protective effects of selenium (Se) against genotoxicity induced by diazinon (DZN) in rat peripheral blood lymphocytes by micronucleus (MN) test. Animals were concurrently administered intraperitoneally with DZN in proper solvent (20 mg/kg body weight (b.w.)) and Se at three different doses (0.5, 1, and 2 mg/kg b.w.) for 30 consecutive days. The positive control group received DZN at the same dose without Se. After 24 h of last injection, 0.5 ml blood of each rat was received and cultured in culture medium for 44 h. The lymphocyte cultures were mitogenically stimulated with cytochalasin B to allow the evaluation of number of MNs in cytokinesis-blocked binucleated cells. Incubation of lymphocytes with DZN induced additional genotoxicity and is shown by increase in MNs frequency in human lymphocytes. Se at low dose of 0.5 mg/kg had a maximum effect and significantly reduced the MNs frequency in cultured lymphocytes ( p < 0.0001) that reduced the frequency of MN from 12.78 ± 0.24% for DZN group to 4.40 ± 0.36. The present study revealed that Se particularly at low doses has a potent antigenotoxic effect against DZN -induced toxicity in rats, which may be due to the scavenging of free radicals and increased antioxidant status.

Rifampicin attenuates the MPTP-induced neurotoxicity in mouse brain

Rifampicin, an antibacterial drug, is highly effective in the treatment of tuberculosis and leprosy. Recently, it has been reported to have neuroprotective effects in in vitro and in vivo models. This study was designed to elucidate its neuroprotective effects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity (known as an in vivo mouse model of Parkinson's disease). Mice were injected intraperitoneally (i.p.) with MPTP (10 mg/kg) four times at 1-h intervals, and brains were analyzed 3 or 7 days later. Rifampicin at 20 mg/kg (i.p., twice) had protective effects against MPTP-induced neuronal damage (immunohistochemical changes in tyrosine hydroxylase) in both the substantia nigra and striatum. Rifampicin also protected against the MPTP-induced depletions of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the striatum. The maximal concentrations of rifampicin between 30 and 240 min after a single rifampicin injection (20 mg/kg, i.p.) were 2.6 microM (at 30 min) in plasma and 0.77 microM (at 60 min) in striatum. Next, the effects of rifampicin on oxidative stress [lipid peroxidation in mouse brain homogenates and free radical-scavenging activity against diphenyl-p-picrylhydrazyl (DPPH)] were evaluated to clarify the underlying mechanism. At 1 microM or more, rifampicin significantly inhibited both lipid peroxidation in the striatum and free radical production. These findings suggest that in mice, rifampicin can reach brain tissues at concentrations sufficient to attenuate MPTP-induced neurodegeneration in the nigrostriatal dopaminergic neuronal pathway, and that an inhibitory effect against oxidative stress may be partly responsible for its observed neuroprotective effects.

Minocycline inhibits oxidative stress and decreases in vitro and in vivo ischemic neuronal damage

The neuroprotective effects of minocycline-which is broadly protective in neurologic-disease models featuring cell death and is being evaluated in clinical trials-were investigated both in vitro and in vivo. For the in vivo study, focal cerebral ischemia was induced by permanent middle cerebral artery occlusion in mice. Minocycline at 90 mg/kg intraperitoneally administered 60 min before or 30 min after (but not 4 h after) the occlusion reduced infarction, brain swelling, and neurologic deficits at 24 h after the occlusion. For the in vitro studies, we used cortical-neuron cultures from rat fetuses in which neurotoxicity was induced by 24-h exposure to 500 microM glutamate. Furthermore, the effects of minocycline on oxidative stress [such as lipid peroxidation in mouse forebrain homogenates and free radical-scavenging activity against diphenyl-p-picrylhydrazyl (DPPH)] were evaluated to clarify the underlying mechanism. Minocycline significantly inhibited glutamate-induced cell death at 2 microM and lipid peroxidation and free radical scavenging at 0.2 and 2 microM, respectively. These findings indicate that minocycline has neuroprotective effects in vivo against permanent focal cerebral ischemia and in vitro against glutamate-induced cell death and that an inhibition of oxidative stress by minocycline may be partly responsible for these effects.