Levels of oxidative stress parameters and the protective effects of melatonin in psychosis model rat testis

Aim： To evaluate the effects of melatonin on antioxidant enzyme levels and histopathologic changes in dizocilpine （MK-801）-induced psychosis model rat testis. Methods： A total of 24 adult male Wistar-Albino rats were divided into three groups with 8 in each. Group I was used as control. Rats in Group II were injected with MK-801 （0.5 mg/kg body weight i.p. for 5 days）. In addition to MK-801, melatonin （50 mg/kg body weight i.p. once a day for 5 days） was injected into the rats in Group Ⅲ. The testes were harvested bilaterally for biochemical and histopathological examinations. Antioxidant enzyme activities, malondialdehyde, protein carbonyl and nitric oxide （NO） levels in testicular tissues were analyzed using spectrophotometric analysis methods. Histopathological examinations of the testes were also performed. Results： MK-801 induced testicular damage, which resulted in significant oxidative stress （OS） by increasing the levels of antioxidant enzymes. The malondialdehyde, protein carbonyl and NO levels were increased in testicular tissues of rats. Treatment with melatonin led to significant decrease in oxidative injury. Administration of melatonin also reduced the detrimental histopathologic effects caused by MK-801. Conclusion： The results of the present study showed that MK-801 cause OS in testicular tissues of rats and treatment with melatonin can reduce the harmful effects＇of MK-801. （Asian JAndro12008 Mar; 10： 259-265）

DNA microarray unravels rapid changes in transcriptome of MK-801 treated rat brain

AIM:To investigate the impact of MK-801 on gene expression patterns genome wide in rat brain regions. METHODS:Rats were treated with an intraperitoneal injection of MK-801 [0.08(low-dose) and 0.16(highdose) mg/kg] or NaC l(vehicle control). In a first series of experiment,the frontoparietal electrocorticogram was recorded 15 min before and 60 min after injection. In a second series of experiments,the whole brain of each animal was rapidly removed at 40 min post-injection,and different regions were separated:amygdala,cerebral cortex,hippocampus,hypothalamus,midbrain and ventral striatum on ice followed by DNA microarray(4 × 44 K whole rat genome chip) analysis.RESULTS:Spectral analysis revealed that a single systemic injection of MK-801 significantly and selectively augmented the power of baseline gamma frequency(30-80 Hz) oscillations in the frontoparietal electroencephalogram. DNA microarray analysis showed the largest number(up- and down- regulations) of gene expressions in the cerebral cortex(378),midbrain(376),hippocampus(375),ventral striatum(353),amygdala(301),and hypothalamus(201) under low-dose(0.08 mg/kg) of MK-801. Under high-dose(0.16 mg/kg),ventral striatum(811) showed the largest number of gene expression changes. Gene expression changes were functionally categorized to reveal expression of genes and function varies with each brain region.CONCLUSION:Acute MK-801 treatment increases synchrony of baseline gamma oscillations,and causes very early changes in gene expressions in six individual rat brain regions,a first report.