Impact of locomotion restraint during the neonatal period on some hormonal and behavoural aspects in male rats

The early stage of neonatal life is considered a crucial period for the development and differentiation of the nervous system and any impairment in the neuro-developmental aspects may result in a life-long modification. Accordingly, this study was designed to investigate the impact of restraint from the 21st day to the 42nd day in rat's neonatal period on some biochemical, behavioural and emotionality _related aspects. At the age of three weeks, young rats were exposed to 21 days of locomotion restraint for 6 h/day after which, the rats of both the control unstressed group and those that were exposed to the stressful regimen were subjected to the behavioural assessments using the exploratory and aggressive behaviour tests. After completion of these tests, the rats were sacrificed to determine the tissue brain cortex acetylcholinesterase [AChE] activity and total protein content. Serum levels of glucose, total cholesterol, testosterone, luteinizing hormone [LH], prolactin [PRL], thyroid stimulating hormone [TSH], thyroxine [T4], triiodothyronine [T3] in addition to the plasma levels of adrenocorticotropin [ACTH] were estimated. The present findings revealed that rats exposed to restraint stress exhibited significant shortcomings in the exploratory test with high rates of emotionality and excitability as revealed by their aggressiveness. These behavioural deviations were concomitant with disturbances in the endocrine balance as indicated by a decline in the levels of serum T3, PRL, testosterone, LH and a rise in plasma ACTH as well as serum glucose and cholesterol levels. The present study explicitly indicates that exposure to stress during the early stage of life results in long-lasting behavioural and neuro-endocrine alterations in the adult rats

Effect of aluminum on some neural aspects of rat offspring and the possible amelioration with antioxidants

This study comprises two experiments, in the first one pregnant rats were administered a daily dose of 360 mg/kg aluminum chloride from the 8[th] to the 20[th] day of gestation. The aluminum [Al] was given either separately or in combination with 100 mg/kg a tocopherol [vitamin E] or with vitamin E plus 500 mg/kg ascorbic acid [vitamin C] via stomach intubation. In the second experiment, pregnant rats were treated with aluminum as in the previous experiment and the offspring born to aluminum-treated mothers were divided into three groups. The first was given the solvent vehicle; the second was treated with vitamin E and the third with vitamin E plus vitamin C. At the postnatal age of 105 days, the offspring of both experiments were sacrificed to determine the level of free amino acids, monoamine neurotransmitters, DNA, RNA and reduced glutathione [GSH], malondialdehyde [MDA], the activities of Na[+] K[+]-ATPase, superoxide dismutase [SOD] in the brain cortex. In addition, total protein content and acetyicholinesterase [AChE] activity in both cerebral cortex and hippocampus tissues were investigated to evaluate the impact of aluminum and the possible ameliorative effects of vitamin E and C. Aluminum residue was measured in the cerebral cortex of normal rats and those prenatally treated with aluminum. Aluminum caused severe physiological perturbation in the brain neurotransmitters. Vitamin E curtailed some of these aluminum-induced physiological perturbations, whereas vitamins E+C given together almost completely ameliorated these perturbations. The results highlight the importance of these two antioxidant vitamins in counteracting the aluminum damaging effect on the rat nervous system. Based on the present results, administration of vitamin E and C concomitantly is recommended to neonates whose mothers at high risk of aluminum contamination as a preventive and a protective measure against the neurological damage caused by aluminum