Effects of zinc deficiency and supplementation on malondialdehyde and glutathione levels in blood and tissues of rats performing swimming exercise

The aim of the study was to investigate the effects of zinc deficiency and supplementation on lipid peroxidation and glutathione levels in blood and in some tissues of rats performing swimming exercise. Forty adult male Sprague-Dawley rats were divided into four groups: group 1, zinc-deficient consisted of swimming rats; group 2 consisted of zinc-supplemented swimming rats; groups 3 and 4 were the swimming and nonswimming controls, respectively. The levels of malondialdehyde and glutathione were measured after 4 wk of zinc-deficient or zinc-supplemented diet and 30 min of swimming exercise daily. The erythrocyte glutathione levels of groups 2 and 4 were significantly higher than those of groups 1 and 3 (p<0.01). The plasma malondialdehyde level of group 1 was significantly higher than all other groups. The glutathione levels in liver, kidney, striated muscle, and testes of group 2 were higher than in the other groups (p<0.01) and higher in kidney and striated muscle of group 3 than in groups 1 and 4 (p<0.01). The tissue malondialdehyde levels of striated muscle, liver, kidney, and testes of group 1 were significantly higher than for all other groups (p<0.01). Our findings suggest that both swimming exercise and zinc deficiency result in an increase of lipid peroxidation in tissues and that zinc supplementation prevents these alterations by the activation of the antioxidant system.     

Effect of long-term swimming exercise on zinc,magnesium, and copper distribution in aged rats

Trace element content of different tissues might be altered by both age and exercise training. We aimed to determine the effects of a 1-yr swimming protocol (60 min/d, 5 day/wk) on tissue levels and the distribution of zinc (Zn), magnesium (Mg), and copper (Cu) in aging rats. Three groups were formed: sedentary and trained old groups and a young control group. Tissue Zn, Mg, and Cu concentrations were measured in the kidney, heart, liver, lungs, and gastrocnemius and soleus muscles. Kidney zinc concentration significantly decreased in the sedentary old group compared to the young control group (p<0.01) and was significantly higher in the trained old group compared to the sedentary old group (p<0.01), whereas Zn levels in the soleus muscle significantly increased in the sedentary old group in comparison to young controls (p<0.05). Tissue Mg concentrations remained unchanged. The sedentary old group exhibited a significant decrease in kidney Cu concentration compared to the young control group (p<0.01). Although kidney Cu levels also decreased in trained old rats in comparison to young controls (p<0.05), they were significantly higher than in sedentary old rats (p<0.01). The decrease in kidney Zn and Cu content as a result of aging was partly prevented by long-term swimming exercise.     

Analysis of zinc and magnesium levels in pinealectomized chicks

Melatonin is the main product of the pineal gland, and trace metals play a critical role in growth and development. The purpose of this study was to assess the serum zinc (Zn) and magnesium (Mg) levels in pinealec-tomized chicks and their possible interactions with the development of spinal deformity. Chicks were divided into two equal groups: unoperated controls (group M) and pinealectomized chicks (group N). Pinealectomies were performed at the age of 3 d. After 8 wk, serum Zn and Mg levels of 10 animals from each group were measured by spectrophotometric assay. The results of analyses were compared using the Mann-Whitney U-test. The correlation between serum Zn and Mg levels were assessed by Spearman's correlation. In this study, it was obvious that the serum Zn levels in group N were significantly lower than those in group M (2.8±0.10 vs 4.2±0.14 ppm; p<0.0005). In contrast, Mg levels in group N was high compared with the values in group M, although there was no significant difference (17.8±0.69 vs 15.7±0.85 ppm; p>0.05). In pinealectomized animals, serum Zn levels declined significantly while serum Mg levels increased, albeit insignificantly. Thus, there was a moderately positive but not statistically significant correlation between Mg and Zn levels in unoperated controls (r=0.273, p>0.05), whereas there was a negative but not statistically significant correlation between Zn and Mg levels in pinealectomized chicks (r=−0.115, p>0.05). In addition, the serum Mg to serum Zn ratio was significantly higher in group N than in the group M control (6.39±0.32 vs 3.75±0.22, respectively; p<0.001). From the results of the current study, it is clear that surgical pinealectomy in newly hatched Hybro Broiler chicks has a significant effect on serum Zn level. However, the serum Mg did not change significantly. Because serum Mg is not a good indicator of Mg status in chicks, it is speculated that other tissues, such as muscle or spine, might productively be explored as a more sensitive Mg biomarker for this model. The present study provides experimental evidence that serum trace metal levels might be affected in pinealectomized animals because of the lack of its main neurohormone melatonin.     

Changes in serum leptin levels in strenuous exercise and its relation to zinc deficiency in rats

This study aimed to investigate the possible changes in serum leptin concentration caused by acute exercise and the effects of zinc deficiency on these changes. Forty male rats were divided into control-control, control-elercise, zinc-deficient-control, and zinc-deficient-exercise groups (10 rats in each). Control-exercise and zinc-deficient-exercise groups performed exercisse at 6 m/min speed on a rodent treadmill for 60 min or until exhaustion. All rats were decapitated 48h after the exercise, and blood samples were collected to determine serum leptin and zinc levels. Serum leptin levels in the zinc-deficient-control group were lower than in the control-control group. The mean exercise time of control-exercise group was significantly longer than the zinc-deficient-exercise group. We conclude that serum leptin levels significantly decrease both 48 h after strenuous exercise and in the zinc-deficient rats, and there is a further decrease in leptin levels when rats fed on a zinc-deficient diet performed exercise.     

游泳运动对低氧性肺动脉高压大鼠肺组织apelin及其受体表达的影响

目的:探讨游泳运动对大鼠肺组织新的小分子活性肽apelin及其受体(APJ)表达的影响。方法:45只雄性大鼠随机分成三组:正常对照组、低氧组(七周)和游泳组(低氧+游泳锻炼七周组,低氧3周后,于每天入低氧舱前行无负重游泳运动60 min,每天1次)。七周后测定各组大鼠平均肺动脉压(mPAP)、右心室与左心室加室间隔的重量比[RV/(LV+S)]、肺细小动脉管壁面积/管总面积(WA/TA)、管腔面积/管总面积(CA/TA)及中膜厚度(PAMT)。免疫蛋白印迹与免疫组化法测定肺组织apelin/APJ的蛋白表达。结果:①低氧组mPAP和RV/(LV+S)比正常对照组分别高73.6%和31.2%(P均<0.01),而游泳组比低氧组分别低21.1%和8.9%(P均<0.05)。②低氧组WA/TA和PAMT较正常对照组分别高70.8%和102%,而游泳组较低氧组分别低24.8%和40.1%(P均<0.01)。低氧组CA/TA较正常对照组低15.1%,而游泳组较低氧组高10.3%(P均<0.01)。③低氧组肺组织apelin蛋白表达较正常对照组上调374%(P<0.01),而APJ蛋白表达下调87.1%(P均<0.01);游泳组肺组织apelin蛋白表达较低氧组下调48%,而APJ蛋白表达上调287%(P均<0.01)。④apelin蛋白主要在血管外膜及炎症细胞胞浆内表达,APJ蛋白主要在血管内膜、外膜及炎症细胞上表达。结论:游泳运动减缓肺动脉高压和肺血管重塑作用可能与调节肺组织apelin/APJ系统的表达有关。     

Determination of the lactate threshold and maximal blood lactate steady state intensity in aged rats

The reliability of the lactate threshold (LT) determined in aged rats and its validity to identify an exercise intensity corresponding to the maximal blood lactate steady state (MLSS) were analyzed. Eighteen male aged Wistar rats (～365 days) were submitted to two incremental swimming tests until exhaustion, consisting of an initial load corresponding to 1% of body mass (BM) and increments of 1% BM at each 3‐min with blood lactate ([lac]) measurements. The LT was determined by visual inspection (LT_V) as well by applying a polynomial function on the [lac]/workload ratio (LT_P) by considering the vertices of the curve. For the MLSS, twelve animals were submitted, on different days, to 3–4 exercise sessions of 30‐min with workload corresponding to 4, 5 or 6% BM. The MLSS was considered the highest exercise intensity at which the [lac] variation was not higher than 0.07 mM.min^?1 during the last 20‐min. No differences were observed for the test‐retest results (4.9 ± 0.7 and 5.0 ± 0.8 %BM for LTv; and 6.0 ± 0.6 and 5.8 ± 0.6 %BM for LTp) that did not differ from the MLSS (5.4 ± 0.5 %BM). The LT identified for aged rats in swimming, both by visual inspection and polynomial function, was reliable and did not differ from the MLSS. Copyright © 2009 John Wiley & Sons, Ltd.     

长期游泳运动对大鼠铁状态的影响

目的：观察不同的运动时间对铁状态的影响。方法：大鼠随机分为3、6、12个月的三个游泳运动组和相应安静组;运动期满后观察血液学铁状态指标和器官非血红素铁(NHI)含量和NHI总含量(TNHI)的变化。结果：与安静组相比,三种不同时间长度的运动均诱导一种具有血浆铁浓度降低、血浆转铁蛋白铁饱和度降低而血红蛋白浓度和红细胞比容得到雏持的血液学低铁状态;这种低铁状态伴有肝、脾、心、肾NHI浓度显著降低,但与运动时间无关;肝、脾和肾TNHI变化与其浓度变化方向一致,但心脏没有显著变化;上述器官TNHI随时间增加而增多。结论：尽管运动诱导的低铁状态类似于铁缺乏中期表现,但由于器官NHI重分布和铁贮存并没有进行性降低,因此,长期运动引起的低铁状态可能是机体内铁代谢对运动的适应,不存在所谓“运动性铁缺乏”现象。     

Chronic aerobic swimming exercise promotes functional and morphological changes in rat ileum

Several studies have reported the gastrointestinal (GI) effects promoted by the physical exercise. Thus, we aimed to evaluate the influence of swimming exercise on the contractile reactivity, lipid peroxidation and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and groups exercised for two (EX2), four (EX4), six (EX6) or eight (EX8) weeks, 5 days/week. Animals were killed; the ileum was removed and suspended in organ baths where the isotonic contractions were recorded. Lipid peroxidation was evaluated by MDA (malondialdehyde) measurement with TBARS (thiobarbituric acid reactive substances) assay and morphology by histological staining. Cumulative concentration-response curves to KCl were attenuated, as the E_max values were changed from 100% (SED) to 63.1±3.9 (EX2), 48.8±3.8 (EX4), 19.4±1.8 (EX6) and 59.4±2.8% (EX8). Similarly, cumulative concentration-response curves to carbamylcholine hydrochloride (CCh) were attenuated, as the E_max values were changed from 100% (SED) to 74.1±5.4 (EX2), 75.9±5.2 (EX4) and 62.9±4.6 (EX6), but not in the EX8 (89.7±3.4%). However, CCh potency was increased in this latter, as the EC₅₀ was altered from 1.0±0.1×10⁻⁶ (SED) to 2.1±0.4×10⁻⁷ (EX8). MDA concentration was altered only in EX4 (44.3±4.4) compared with SED (20.6±3.6 μmol/l). Circular layer was reduced in SED when compared with the exercised groups. Conversely, longitudinal layer was increased. In conclusion, chronic swimming exercise reduces the ileum contraction, equilibrates the oxidative damage and promotes changes in tissue size to establish an adaptation to the exercise.     

Effects of zinc and melatonin deficiency on testicular tissue of rats

The present study was designed to investigate the effects of zinc and/or melatonin deficiency on rat testes. A total of 24 adult male Sprague-Dawley rats were used in this study. The rats were divided into four groups of six rats each, as follows: (I) controls, (II) zinc deficient, (III) pinealectomized, zinc normal, and (IV) pinealectomized, zinc deficient. The plasma zinc levels in the control group were higher than in all the other groups (p<0.01), and those of the zinc-deficient groups II and IV were significantly lower than for group III (p<0.01). The melatonin levels in the controls were also significantly higher than for all other groups (p<0.01) There was no significant difference in sperm production between the controls and the group of animals that had no epiphysis. A significant suppression was observed in the spermatogenetic activity of the zinc-deficient groups (p<0.01). The suppression was higher in group II than in group IV. These results indicate that testicular damage caused by zinc deficiency may be reduced by melatonin deficiency.     

Acute supplementation of valine reduces fatigue during swimming exercise in rats

We investigated the respective effects of the acute supplementation of valine, leucine, and isoleucine on metabolism-related markers by administering a swimming exercise test to rats. As a behavioral analysis, we evaluated the effect of valine and that of leucine on spontaneous activity after exercise. Acute supplementation of valine before exercise significantly suppressed the depression of the liver glycogen and the blood glucose after exercise, whereas leucine decreased the blood glucose and isoleucine had no effect. Valine or leucine supplementation significantly decreased the plasma corticosterone level after exercise, while isoleucine had no effect. In the behavioral analysis, valine significantly increased the spontaneous activity after exercise, whereas leucine had no effect. These results indicate that in rats, the acute supplementation of valine, not leucine or isoleucine, is effective for maintaining liver glycogen and blood glucose and increasing spontaneous activity after exercise, which could contribute to the reduction of fatigue during exercise.     

The relation between reduced serum melatonin levels and zinc in rats with induced hypothyroidism

The objective of the study was to explore the changes in melatonin and zinc levels in rats with induced hypothyroidism. Thirty adult male rats used in the study were allocated to three groups with equal numbers. Group 1: General control group which was not subjected to any procedure. Group 2: Sham-hypothyroidism group to which was administered 10 mg kg(-1) intraperitoneal (i.p.) physiologic saline (0.09% NaCl) for 4 weeks. Group 3: Hypothyroidism group which was supplemented with intraperitoneal 10 mg kg(-1) propylthiouracil (PTU) for 4 weeks. Blood samples collected from all animals at the end of the study by decapitation were analysed for serum Total T4 (TT4), Total T3 (TT3), Free T4 (FT4), Free T3 (FT3) (ELISA) as well as for melatonin (RIA) hormones and zinc levels (atomic emission). Comparison of the study groups in terms of thyroid hormones, melatonin and zinc levels showed that TT4, TT3, FT4, FT3, melatonin and zinc levels in group 3 were lower than those in groups 1 and 2 (p < 0.01). These parameters were not different in groups 1 and 2. The results of the study demonstrate that PTU supplementation for 4 weeks results in a significant inhibition in both melatonin and zinc levels. Inhibited melatonin levels may result from the decrease in zinc levels.     

Improved reliability of the urine lactate concentration under controlled hydration after maximal exercise

Context: Urine lactate may be a novel biomarker of lactate production capacity but its reliability has been unsatisfactory so far.

Objective: To compare the reliability of urine lactate between controlled hydration and no hydration after maximal exercise.

Material and methods: Athletes performed swimming exercise four times: two followed by consumption of 1?L of water and two followed by no water intake. Blood and urine lactate was measured.

Results: The reliability of urine lactate was good and similar to that in blood only after controlled hydration. Blood and urine lactate were correlated under both hydration conditions.

Discussion and conclusion: Controlled hydration after exercise provides satisfactory reliability of urine lactate.     

Gentle exercise with a previously inactive muscle group hastens the decline of blood lactate concentration after strenuous exercise

The aim of this study was to elucidate the mechanism by which the disappearance of blood lactate following severe exercise is enhanced during active recovery in comparison with recovery at rest. Rates of decline of arterialised venous blood lactate concentrations in man after maximal one-leg exercise were compared during four different modes of recovery: passive (PR), exercise of the muscles involved in the initial exercise (SL), exercise of the corresponding muscles in the hitherto-inactive leg (OL), or exercise of one arm (RA). Recovery exercise workloads were each 40% of the onset of blood lactate accumulation (OBLA) for the limb used. In comparison with PR, SL and OL accelerated the fall in blood lactate to similar extents whereas RA was without effect. The first-order rate constant (min-1) for decline of arterialised venous blood lactate concentration after the intense exercise was 0.027 (0.003) in PR, 0.058 (0.025) in SL, 0.034 (0.002) in OL, and in RA was 0.028 (0.002) [mean (SEM), n = 6 subjects]. Preliminary studies had shown that RA in isolation elevated blood lactate whereas SL and OL did not. Thus, with appropriate workloads, exercise of either hitherto active or passive muscles enhanced blood lactate decline during recovery from intense exercise. This suggests that the effect resulted principally from the uptake and utilisation of lactate in the circulation by those exercising muscles rather than from increased transport of lactate to other sites of clearance by sustained high blood flow through the previously active muscles.     

The effect of swimming exercise and powdered-Salicornia herbacea L. ingestion on glucose metabolism in STZ-induced diabetic rats

Purpose

The purpose of this study is to observe the effects of Salicornia herbacea L. powder ingestion on carbohydrate metabolism in STZ-induced diabetic rats.

Methods

To achieve this objective, 35 Sprague-Dawley male rats were raised with feed mixed with Salicornia herbacia L. powder and given specific periods to swim for 5 weeks. There was no significant difference in the insulin increase rate while ingesting Salicornia herbacea L. powder and simultaneously exercising.

Results

Compared to the diabetes mellitus group, HOMA-IR was significantly decreased in the diabetes mellitus + exercise group, diabetes mellitus + Salicornia herbacea group, and the diabetes mellitus + Salicornia herbacea + exercise group. However, changes in blood glucose were significant in each group. Thus, for the result of GLUT-4 and GLUT-2, which are the glycose transporters of the liver and muscle, diabetes mellitus + exercise group, diabetes mellitus + Salicornia herbacea group, and diabetes mellitus + Salicornia herbacea + exercise group showed significantly higher expressions. The glycogen concentration of the liver and muscle was significantly increased in the diabetes mellitus + exercise group, diabetes mellitus + Salicornia herbacea group, and diabetes mellitus + Salicornia herbacea + exercise group.

Conclusion

With the results above, it seems that taking Salicornia herbacea L. powder and exercise will help prevent various diabetic complications. Therefore, the findings of this study could justify Salicornia herbacea L. powder with its basal data of physiological activities and pharmacological components as a type of health functional food.     

Effect of exercise training on swimming performance,survival under predation and hypoxia tolerance in an endangered fish species in China

Poor swimming performance and low hypoxia tolerance have been suggested as the main reasons for the dramatic decrease in the wild population of Chinese sucker. The present study aimed to investigate the potential for exercise training to enhance swimming performance and hypoxia tolerance in this fish species targeted for stocking enhancement. Fish were exercise trained (force to swim against a flow) once daily, twice daily or not exercise trained for 20 d and then detrained for 10 d (a period of nontraining). Training showed no significant effect on anaerobic swimming performance.. The fish from both training groups showed lower hypoxia tolerance and a lower survival rate under predation. Thus, the present study suggested thatexercise training showed little effect or even a negative effect on physiological function in Chinese sucker, and the forced training might not be the proper protocol to apply for improving the stocking enhancement of Chinese sucker..