Cholesterol-Lowering and Antioxidant Effects of Pork-Liver Protein Hydrolysate in Otsuka Long-Evans Tokushima Fatty Rats

In this study, we investigated the effects of a porcine liver protein hydrolysate (PLH) diet on lipid metabolism in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type II diabetes. OLETF rats (20-wk-old males) were pair-fed with either a PLH diet containing 20% PLH or a casein diet for 14 wk. Dietary PLH significantly lowered serum cholesterol and phospholipid concentrations, mainly by decreasing low-density lipoprotein and high-density lipoprotein fractions. Fecal cholesterol was significantly increased in the PLH diet group; however, the total bile acid concentration in the feces was not significantly different between the groups. In addition, the PLH diet significantly decreased serum thiobarbituric acid reactive substance concentrations. These results suggest that dietary PLH exerts hyperlipidemic and antioxidant effects, indicating that it is a novel functional food ingredient.

Effect of octreotide on oxidative stress in the erythrocyte and kidney tissue in adriamycin-induced experimental nephrotic syndrome model

INTRODUCTION

Nephrotic syndrome (NS) is one of the reasons of end-stage kidney disease, and elucidating the pathogenesis and offer new treatment options is important. Oxidative stress might trigger pathogenesis systemically or isolated in the kidneys. Octreotide (OCT) has beneficial antioxidant effects. We aimed to investigate the source of oxidative stress and the effect of OCT on experimental NS model.

METHODS

Twenty-four non-uremic Wistar albino rats were divided into 3 groups. Control group, 2 mL saline intramuscular (im); NS group, adriamycin 5 mg/kg intravenous (iv); NS treatment group, adriamycin 5 mg/kg (iv) and OCT 200 mcg/kg (im) were administered at baseline (Day 0). At the end of 21 days, creatinine and protein levels were measured in 24-hour urine samples. Erythrocyte and renal catalase (CAT) and thiobarbituric acid reactive substance (TBARS) were measured. Renal histology was also evaluated.

RESULTS

There was no significant difference among the 3 groups in terms of CAT and TBARS in erythrocytes. Renal CAT level was lowest in NS group, and significantly lower than the control group. In treatment group, CAT level significantly increased compared with NS group. In terms of renal histology, tubular and interstitial evaluations were similar in all groups. Glomerular score was significantly higher in NS group compared with control group and it was significantly decreased in treatment group compared to NS group.

CONCLUSIONS

Oxidative stress in NS might be due to the decrease in antioxidant protection mechanism in kidney. Octreotide improves antioxidant levels and histology in renal tissue and might be a treatment option.

Effects of Two-Week Betaine Supplementation on Apoptosis, Oxidative Stress, and Aerobic Capacity after Exhaustive Endurance Exercise

This study evaluated the effects of 2 weeks of betaine supplementation on apoptosis, oxidative stress, and aerobic capacity after exhaustive endurance exercise (EEE). A double-blind, crossover, and counterbalanced design was adopted, with 10 healthy male participants asked to consume betaine (1.25 g of betaine mixed with 300 mL of sports beverage, twice per day for 2 weeks) or placebo (300 mL of sports beverage). All participants performed a graded exercise test on a treadmill to determine the maximal oxygen consumption (VO2max) before supplementation and then performed the EEE test at an intensity of 80% VO2max after 2 weeks of supplementation. The time to exhaustion, peak oxygen consumption, maximal heart rate, and average heart rate were recorded during the EEE test. Venous blood samples were drawn before, immediately after, and 3 h after the EEE test to assess apoptosis and the mitochondrial transmembrane potential (MTP) decline of lymphocytes as well as the concentrations of thiobarbituric acid reactive substance and protein carbonyl. The results indicated that lymphocyte apoptosis was significantly higher immediately after and 3 h after EEE than before exercise in participants in the placebo trial. However, lymphocyte apoptosis exhibited no significant differences among the three time points in participants in the betaine trial. Moreover, apoptosis in the betaine trial was significantly lower immediately after and 3 h after exercise compared with the placebo trial. No differences were noted for other variables. Thus, 2 weeks of betaine supplementation can effectively attenuate lymphocyte apoptosis, which is elevated by EEE. However, betaine supplementation exhibited no effects on MTP decline, oxidative stress, or aerobic capacity.

High-intensity exercise-induced oxidative stress in sedentary pre-pubertal & post-pubertal boys: A comparative study

Background & objectives

High-intensity exercise results in oxidative stress in adult population. Impact of pubertal attainment on high-intensity exercise-induced oxidative stress in sedentary paediatric population has not been investigated in detail. The present study was conducted to investigate the extent of high-intensity exercise-induced oxidative stress in sedentary pre- and post-pubertal boys through estimation of serum thiobarbituric acid reactive substances (TBARS), total thiol content and activities of superoxide dismutase (SOD) and catalase (CAT).

Methods

Sixty four sedentary pre-pubertal (n=32, age = 10.21±0.67 yr) and post-pubertal (n=32, age = 15.58±0.47 yr) boys performed incremental treadmill running exercise at 80 per cent of the age predicted maximum heart rate till volitional exhaustion. Blood sample (5 ml) was drawn from each individual before and after the exercise for estimation of oxidative stress markers.

Results

Pre-exercise SOD activity and total thiol level showed significant positive relationship with age and were significantly higher in post-pubertal boys. Serum TBARS level, SOD and CAT activities increased while total thiol content decreased in both the groups following exercise. Post-exercise percentage change in TBARS, SOD activity and total thiol level was significantly higher in post-pubertal boys, and these variables had significant positive relationship with age. No significant intergroup variations were noted in CAT activity before or after exercise.

Interpretation & conclusions

Extent of post-exercise oxidative stress increased significantly with attainment of puberty. However, baseline and post-exercise antioxidation status also increased significantly as a function of age with pubertal maturation allowing the post-pubertal boys to counter relatively higher oxidative stress more efficiently than their pre-pubertal counterparts. Post-exercise upregulation in CAT activity might not be influenced by age or pubertal maturation in this age group.

Physiological Response of Orchids to Mealybugs (Hemiptera: Pseudococcidae) Infestation

The harmfulness of mealybugs resulting from sucking plant sap, secreting honeydew, and transmitting plant viruses can give them the status of serious pests. This study documents the influence of Pseudococcus maritimus (Ehrhorn) and Pseudococcus longispinus (Targioni Tozzetti) infestation on alterations in selected physiological parameters of Phalaenopsis x hybridum 'Innocence'. The condition of the cytoplasmic membranes was expressed as the value of thiobarbituric acid reactive substances. We have determined changes in the activities of catalase and guaiacol peroxidase and measured the following chlorophyll fluorescence parameters: maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield (Y), photochemical quenching (qP), and nonphotochemical quenching (qN). The strongest physiological response of orchids was recorded in the initial period of mealybugs infestation. Prolonged insect feeding suppressed lipid peroxidation, peroxidase and catalase activity, as well as photosynthesis photochemistry. The pattern of changes was dependent on mealybug species. This indicated the complexity of the processes responsible for plant tolerance. Data generated in this study have provided a better understanding of the impact of two mealybug species infestation on Phalaenopsis and should be useful in developing pest management strategies.

Oxidative Stress in the Heart of Rats Infected with Trypanosoma evansi

This study was conducted to investigate the occurrence of oxidative stress in the heart tissue of rats infected with Trypanosoma evansi. Rats were divided into 2 groups (A and B) with 12 animals each, and further subdivided into 4 subgroups (A1 and A2, 6 animals/each; and B1 and B2, 6 animals/each). Animals in the groups B1 and B2 were subcutaneously inoculated with T. evansi. Thiobarbituric acid reactive substances (TBARS), superoxide dismutase activity (SOD), glutathione S-transferase activity (GST), reduced glutathione activity (GSH), and non-protein thiols (NPSH) in the heart tissue were evaluated. At day 5 and 15 post-infection (PI), an increase in the TBARS levels and a decrease in the SOD activity (P<0.05) were observed. GSH and GST activities were decreased in infected animals at day 15 PI (P<0.05). Considering the proper functioning of the heart, it is possible that the changes in the activity of these enzymes involved in the oxidative stress may be related, at least in part, in the pathophysiology of rats infected with T. evansi.

Phosphorus deficiency enhances aluminum tolerance of rice (Oryza sativa) by changing the physicochemical characteristics of root plasma membranes and cell walls

The negative charge at the root surface is mainly derived from the phosphate group of phospholipids in plasma membranes (PMs) and the carboxyl group of pectins in cell walls, which are usually neutralized by calcium (Ca) ions contributing to maintain the root integrity. The major toxic effect of aluminum (Al) in plants is the inhibition of root elongation due to Al binding tightly to these negative sites in exchange for Ca. Because phospholipid and pectin concentrations decrease in roots of some plant species under phosphorus (P)-limiting conditions, we hypothesized that rice (Oryza sativa L.) seedlings grown under P-limiting conditions would demonstrate enhanced Al tolerance because of their fewer sites on their roots. For pretreatment, rice seedlings were grown in a culture solution with (+P) or without (-P) P. Thereafter, the seedlings were transferred to a solution with or without Al, and the lipid, pectin, hemicellulose, and mineral concentrations as well as Al tolerance were then determined. Furthermore, the low-Ca tolerance of P-pretreated seedlings was investigated under different pH conditions. The concentrations of phospholipids and pectins in the roots of rice receiving -P pretreatment were lower than those receiving +P pretreatment. As expected, seedlings receiving the -P pretreatment showed enhanced Al tolerance, accompanied by the decrease in Al accumulation in their roots and shoots. This low P-induced enhanced Al tolerance was not explained by enhanced antioxidant activities or organic acid secretion from roots but by the decrease in phospholipid and pectin concentrations in the roots. In addition, low-Ca tolerance of the roots was enhanced by the -P pretreatment under low pH conditions. This low P-induced enhancement of low-Ca tolerance may be related to the lower Ca requirement to maintain PM and cell wall structures in roots of rice with fewer phospholipids and pectins.

Cytotoxicity and the induction of the stress protein Hsp 70 in Chang liver cells in response to zearalenone-induced oxidative stress

Zearalenone (ZEN) has been implicated in several cases of mycotoxicosis in farm animals and humans. The toxic effects of ZEN have been well characterized, but little is known regarding the mechanisms of ZEN toxicity, including the involvement of the oxidative stress pathway. Using Chang liver cells as a model, the aim of this study was to determine if ZEN could elevate the expression of the heat shock protein Hsp 70, induce cytotoxicity and modulate the levels of glutathione (GSH) and thiobarbituric acid reactive substance (TBARS). In addition, the cytoprotective effects of N-acetylcysteine amide (NACA) pre-treatment were assessed. Finally, the involvement of oxidative stress in ZEN-induced toxicity was confirmed. The results of this study demonstrated that ZEN-induced Hsp 70 expression in a dose- and time-dependent manners. This effect occurred at low-ZEN concentrations, and could therefore be considered a biomarker of ZEN-induced toxicity. The cytotoxicity was reduced when Chang liver cells were exposed to sub-lethal heat shock prior to ZEN treatment, demonstrating a cytoprotective effect of Hsp 70. This cytoprotective effect suggested that Hsp 70 might play a key role in the cellular defense mechanism. When cells were pre-treated with NACA prior to ZEN treatment, the cells were also protected from toxicity. This NACA cytoprotective effect suggested the involvement of oxidative stress in ZEN-induced toxicity, and this mechanism was supported by reduced Hsp 70 expression, inhibited cytolethality, increased GSH levels and decreased TBARS formation when cells were pre-treated with NACA prior to ZEN exposure. Our data clearly demonstrated that ZEN induced cytotoxicity in Chang liver cells by inhibiting cell proliferation, decreasing GSH levels and increasing TBARS formation in a dose-dependent manner. ZEN also, induced Hsp 70 expression, and the side effects of ZEN were significantly alleviated by pre-treatment with NACA. Oxidative stress is likely to be one of the primary pathways of ZEN toxicity. This oxidative stress may contribute, at least in part, to the mechanism of ZEN-induced cytotoxicity.

Inhibitory Response of Raphanus sativus on Lipid Peroxidation in Albino Rats

In the present study, inhibitory effect of the methanol extract of Raphanus sativus root on lipid peroxidation has been carried out in normal rats. Graded doses of methanol extract of root of the plant (40, 80 and 120 mg kg(-1) body weight) were administered orally for 15 days to experimental treated rats. Distilled water was administered to experimental control rats. At the end of experiment, rats were killed by decapitation after ether anesthesia. Blood and liver were collected to measure thiobarbituric acid reactive substance, reduced glutathione and activity of catalase. Results indicated that the extract of R. sativus root reduced the levels of thiobarbituric acid reactive substance significantly in all experimental treated groups (P < 0.05) as compared to the experimental control group. It also increased the levels of reduced glutathione and increased the activity of catalase. In vitro experiments with the liver of experimental control and experimental treated rats were also carried out against cumene hydroperoxide induced lipid peroxidation. The extract inhibited in vitro cumene hydroperoxide induced lipid peroxidation. R. sativus inhibits lipid peroxidation in vivo and in vitro. It provides protection by strengthening the antioxidants like glutathione and catalase. Inclusion of this plant in every day diet would be beneficial.