Intracerebroventricular injection of kisspeptin in male rats activates hypothalamo-pituitary-gonadal axis, but not hypothalamo-pituitary-adrenal axis.

Kisspeptin is an important hormone involved in the stimulation of the hypothalamo-pituitary gonadal (HPG) axis. The HPG axis can be suppressed in certain conditions such as stress, which gives rise to the activation of the hypothalamo-pituitary-adrenal (HPA) axis. However, the physiological role of kisspeptin in the interaction of HPG and HPA axis is not fully understood yet. This study was conducted to investigate the possible effects of central kisspeptin injection on HPG axis as well as HPA axis activity. Adult male Wistar rats were randomly divided into seven groups as followed: sham (control), kisspeptin (50 pmol), P234 (1 nmol), kisspeptin + p234, kisspeptin + antalarmin (0.1 µg), kisspeptin + astressin 2B (1 µg), and kisspeptin + atosiban (300 ng/rat) (n = 10 each group). At the end of the experiments, the hypothalamus, pituitary, and serum samples of the rats were collected. There was no significant difference in corticotropic-releasing hormone immunoreactivity in the paraventricular nucleus of the hypothalamus, serum adrenocorticotropic hormone, and corticosterone levels among all groups. Moreover, no significant difference was detected in pituitary oxytocin level. Serum follicle-stimulating hormone and luteinizing hormone levels of the kisspeptin, kisspeptin + antalarmin, and kisspeptin + astressin 2B groups were significantly higher than the control group. Serum testosterone levels were significantly higher in the kisspeptin kisspeptin + antalarmin, kisspeptin + astressin 2B, and kisspeptin + atosiban groups compared to the control group. Our findings suggest that central kisspeptin injection causes activation in the HPG axis, but not the HPA axis in male rats.

Chronic immobilization stress induces anxiety-related behaviors and affects brain essential minerals in male rats.

Alterations of essential elements in the brain are associated with the pathophysiology of many neuropsychiatric disorders. It is known that chronic/overwhelming stress may cause some anxiety and/or depression. We aimed to investigate the effects of two different chronic immobilization stress protocols on anxiety-related behaviors and brain minerals. Adult male Wistar rats were divided into 3 groups as follows (n = 10/group): control, immobilization stress-1 (45 minutes daily for 7-day) and immobilization stress-2 (45 minutes twice a day for 7-day). Stress-related behaviors were evaluated by open field test and forced swimming test. In the immobilization stress-1 and immobilization stress-2 groups, percentage of time spent in the central area (6.38 ± 0.41% and 6.28 ± 1.03% respectively, p < 0.05) and rearing frequency (2.75 ± 0.41 and 3.85 ± 0.46, p < 0.01 and p < 0.05, respectively) were lower, latency to center area (49.11 ± 5.87 s and 44.92 ± 8.04 s, p < 0.01 and p < 0.01, respectively), were higher than the control group (8.65 ± 0.49%, 5.37 ± 0.44 and 15.3 ± 3.32 s, respectively). In the immobilization stress-1 group, zinc (12.65 ± 0.1 ppm, p < 0.001), magnesium (170.4 ± 1.7 ppm, p < 0.005) and phosphate (2.76 ± 0.1 ppm, p < 0.05) levels were lower than the control group (13.87 ± 0.16 ppm, 179.31 ± 1.87 ppm and 3.11 ± 0.06 ppm, respectively). In the immobilization stress-2 group, magnesium (171.56 ± 1.87 ppm, p < 0.05), phosphate (2.44 ± 0.07 ppm, p < 0.001) levels were lower, and manganese (373.68 ± 5.76 ppb, p < 0.001) and copper (2.79 ± 0.15 ppm, p < 0.05) levels were higher than the control group (179.31 ± 1.87 ppm, 3.11 ± 0.06 ppm, 327.25 ± 8.35 ppb and 2.45 ± 0.05 ppm, respectively). Our results indicated that 7-day chronic immobilization stress increased anxiety-related behaviors in both stress groups. Zinc, magnesium, phosphate, copper and manganese levels were affected in the brain.

Long-term metabolic cage housing increases anxiety/depression-related behaviours in adult male rats.

There are several reports on unfavourable effects of metabolic cage housing on animal welfare mainly due to the characteristic structures of these cages such as single housing and grid flooring. This study was aimed to compare the effects of long-term metabolic cage housing and conventional housing (normal grouped housing in standard cages) on the anxiety/depression-like behaviours in male rats. Anxiety/depression-related behaviours were evaluated by use of forced swimming test and open field test. Swimming and climbing were significantly lower and immobility duration higher in the metabolic cage group. In the open field test, total distance, mean velocity, time spent in the central area, zone transition, grooming, and rearing scores were significantly lower in the metabolic cage. Moreover, serum corticosterone level was higher in the metabolic cage group. The results of the study indicate that long-term metabolic cage housing may cause an increase in the anxiety- and depression-related behaviours in male rats.

Preventive role of magnesium on skeletal muscle ischemia-reperfusion injury-an experimental study.

The present study aims to explore whether Mg infusion has a preventive effect on ischemia-reperfusion injury in rats. A total of 20 Sprague-Dawley-type adult male rats were used. In group 1 (control), 0.9% isotonic solution was administered. In group 2 (experiment), magnesium sulfate (0.5 mg per 100 g) was administered. Ischemia was induced for 15 min for the two groups. Magnesium (Mg), interleukin 8 (IL-8), and malondialdehyde levels were analyzed in blood, while edema, neutrophil infiltration, eosinophilia, loss of striation, and nucleolization were evaluated in histopathological examination. Mg levels in the experiment group were higher than those in the control group after ischemia-reperfusion (p < 0.05). In the control group, postischemia and postreperfusion IL-8 values were higher than preoperative values (p < 0.05). As for eosinophilia and loss of striation values, these were higher in the experiment group after ischemia-reperfusion than the values in the control group (p < 0.05). Histopathologically, Mg infusion cannot prevent the tissue injury triggered in ischemia-reperfusion periods. Eosinophilia can be one of the major and earliest markers of ischemia-reperfusion injury.

The effect of low dose zinc supplementation to serum estrogen and progesterone levels in post-menopausal women.

The objective of the present study is to investigate how low-dose zinc supplementation for 2 weeks in the post-menopausal period influences levels of estrogen and progesterone in the serum. The study registered 32 natural menopause patients, who were allocated to four groups with equal number of patients. Group 1, control group, which was not subjected to any procedure. Group 2, the group that was supplemented with 15 mg/day zinc sulfate for 2 weeks. Group 3, the group that was given hormone replacement therapy (0.625 mg estrogen + 5 mg medroxyprogesterone acetate/day) for 2 weeks. Group 4, the group that received hormone replacement therapy (0.625 mg estrogen + 5 mg medroxyprogesterone acetate/day) and zinc sulfate (15 mg/day) for 2 weeks. Blood samples were collected twice from each subject, once at the beginning of the study, and once at the end of the 4-week procedure to determine estrogen (E2) and progesterone levels. Variance analysis was employed in the statistical evaluation of data. Level of significance was set at p < 0.05. No significant difference was found between the estrogen and progesterone levels of groups 1 and 2. Groups 3 and 4 had higher estrogen and progesterone levels than groups 1 and 2 (p < 0.05). Estrogen and progesterone levels in groups 3 and 4 were not different. Results of the study show that low-dose zinc supplementation to post-menopausal women for 2 weeks does not have a significant effect on the concerned parameters.

Circulating leptin, zinc, and copper levels after extracorporeal circulation.

OBJECTIVE: The role of leptin in the acute stress response to extracorporeal circulation has been well documented, however, the relationship between leptin and zinc has not been investigated previously. We aimed to research the circulating leptin, zinc, and copper levels before, during, and after the extracorporeal circulation, and effect of preoperative zinc administration to these. METHODS: Twenty patients who were taken to elective coronary artery bypass grafting operations using extracorporeal circulation were taken to this research and divided into two equal groups (n1, n2). In both groups blood samples were taken just before the operation (T0), at the end of operation (T1), and at the first postoperative day (T2). In the second group (n2) oral zinc (50 mg, once a day) was administered to patients for 5 days, preoperatively. The serum leptin, zinc, and copper levels were studied. RESULTS: In group n1 circulating leptin levels were significantly increased at T2 when compared to T0 and T1 (p<0.05); zinc levels were decreased at T2 when compared to T0 and T1 (p<0.05); copper levels were decreased at T2 when compared to T0 (p<0.05), and decreased at T1 when compared to T0 (p<0.05). In group n2 circulating leptin levels were significantly increased at T2 when compared to T0 and T1 (p<0.05); zinc levels were decreased at T2 when compared to T0 and T1 (p<0.05); copper levels were increased at T2 when compared to T1 (p<0.05). CONCLUSIONS: These results indicate that circulating leptin levels increase after the extracorporeal circulation as an acute response, while zinc and copper levels decrease at the same period. Preoperative zinc administration does not prevent the leptin response after extracorporeal circulation.

Methylprednisolone prevents inflammatory reaction occurring during cardiopulmonary bypass: effects on TNF-alpha, IL-6, IL-8, IL-10.

OBJECTIVE: This study examined the correlation between tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-8, IL-10 and methylprednisolone pretreatment. METHODS: This is a prospective, randomized and double-blinded study. Sixty patients undergoing coronary artery bypass grafting (CABG) were randomized to receive either intravenous methylprednisolone (n = 30, Group M) or intravenous placebo (n = 30, Group S). The patients received intravenously either 30 mg/kg methylprednisolone (Group M) or placebo (Group S) 10 min before and after cardiopulmonary bypass (CPB). In an intensive care unit (ICU), four additional doses were given at 6-hourly intervals. Blood samples for the measurements of TNF-alpha, IL-6, IL-8 and IL-10 were obtained before induction of anaesthesia (T0 = control value), after induction (T1), before starting CPB (T2), after aortic declamping (T3), at the end of CPB (T4) and 6 hours (T5), 12 hours (T6) and 24 hours (T7) after skin closure. Creatine kinase (CK) and creatine kinase isoenzyme MB (CK-MB) were evaluated at the following intervals: T0, T5, T6 and T7. RESULTS: When compared with the control value, TNF-alpha, IL-6 and IL-8 significantly increased in Group S and Group M (p < 0.05), but these values were significantly greater in Group S than in Group M (p < 0.05). In comparison with the control value, IL-10 increased in both groups (p < 0.05), but was significantly greater in Group M than in Group S (p < 0.05). CK and CK-MB were increased in both groups in postoperative values compared to control values. In Group S, CK and CK-MB levels were significantly lower than in Group M (p < 0.05). CONCLUSION: In this study, we have found that preoperative administration of methylprednisolone has decreased TNF-alpha, IL-6 and IL-8 release, and increased the perfusing IL-10 levels after CPB. Thus, methylprednisolone may decrease the inflammatory response during the CPB procedure.