Oxidative stress, nitric oxide and prostaglandin E2 levels in the gastrointestinal tract of aging rats

The effect of low or high molecular weight oat beta-glucans on the inflammatory and oxidative stress status in the colon of rats with LPS-induced enteritis

PURPOSE

The aim of the study was to investigate the protective effect of low and high molecular weight beta-glucans on the chosen immunological parameters, markers of antioxidative potential in rats' colon tissue, the number of lactic acid bacteria (LAB) and the concentration of short-chain fatty acids (SCFA) in rats' faeces.

METHODS

The experiment was carried out on 72 8-week old male Sprague-Dawley rats: control (n = 36) and experimental (n = 36). In half of the animals from each group enteritis was induced by LPS (10 mg kg(-1)). Rats from the experimental group were divided into two groups receiving high (GI) or low (GII) molecular weight beta-glucans for 6 consecutive weeks.

RESULTS

LPS evoked enteritis in all the treated animals, manifested by changes in the levels of IL-10, IL-12 and TNF-alpha, as well as in the number of intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) in the colon tissue. Dietary supplementation with beta-glucans following LPS treatment partially reversed this effect. The changes in SCFA concentration were noted, indicating an improvement of the fermentation process in the colon. This effect coincided with an increased number of LAB, pointing at the prebiotic properties of beta-glucans. The positive influence of beta-glucans was also manifested by the improved values of antioxidative potential markers (TAS, SOD, GR and GPx activity, TBARS concentration), noted especially in rats with LPS-induced enteritis. This influence was more pronounced in the case of low molecular weight oat beta-glucan (GII).

CONCLUSIONS

The present study showed a positive effect of beta-glucans, especially the low molecular weight form, on the colon tissue of healthy rats, as well as animals with LPS-induced enteritis.

Anti-oxidative effects produced by environmental enrichment in the hippocampus and cerebral cortex of male and female rats

Both physical and intellectual activity may reduce the incidence of neurodegenerative disorders. There is evidence that environmental enrichment (EE) can induce profound behavioral, neurochemical and neuroanatomical changes, thus producing lasting improvements in memory and learning tasks. In this study we evaluated the anti-oxidative effects produced by EE in the hippocampus and the cerebral cortex of male and female rats. The animals had been reared in either EE or control conditions. The parameters studied were: thiobarbituric acid reactive substances (TBARS), protein oxidation, total radical antioxidant parameter, catalase, superoxide dismutase and superoxide anion activity. The results showed that our EE protocol reduced markers of oxidative stress in the hippocampus and in the cerebral cortex. Overall, the measures taken in the two cerebral regions revealed that EE rats showed higher values for antioxidant measures and lower values for oxidative stress parameters than control animals. More importantly, a consistent sex difference was found, indicating that in female rats the hippocampus and cerebral cortex are plastic brain regions receptive to external stimulation such as EE. Although EE males have higher levels for antioxidant capacity, catalase and SOD, it is likely that females do not need to activate all the antioxidant defenses since they have a greater capacity to assimilate external stimuli. This is suggested by the similarity of protein oxidation and TBARS levels in hippocampus in both sexes, and the even lower levels of protein oxidation and superoxide anion activity in the cerebral cortex in EE females.

Changes in nerve-mediated contractility of the lower urinary tract in a mouse model of premature ageing

BACKGROUND AND PURPOSE

A high incidence of lower urinary tract disorders is associated with ageing. In the senescent-accelerated prone (SAMP8) mouse strain and the senescent-accelerated resistant (SAMR1) strain, we compared smooth muscle contractility in responses to intrinsic neurotransmitters, both in the bladder and urethra.

EXPERIMENTAL APPROACH

We analysed micturition frequency, the changes in muscle tension induced by electrical field stimulation or agonist administration, the density of nerves (adrenergic, cholinergic and nitrergic) and interstitial cells (ICs), as well as cGMP accumulation in bladder and urethral preparations.

KEY RESULTS

Senescent mice of the SAMP8 strain displayed increased micturition frequency and excitatory contractility of neurogenic origin in the bladder. While cholinergic nerve density remained unchanged, there was a mild sensitization to ACh in male mice. Potentiation in the detrusor may be also provoked by the stronger contribution of ATP, together with reduced adrenergic innervation in males and COX-derived prostanoid production in females. The greater excitatory contractility in the urethra was probably due to the sensitization to noradrenaline, in conjunction with attenuated nitrergic relaxation. There were also fewer neuronal NOS immunoreactive (ir) nerves and vimentin-positive ICs, although the sildenafil- and diethylamine-NONOate-induced relaxations and cGMP-ir remained unchanged.

CONCLUSIONS AND IMPLICATIONS

Premature senescent mice exhibit bladder and urethral hyperexcitability, coupled with reduced urethral relaxation of neurogenic origin, which could model the impaired urinary function in elderly humans. We propose that senescence-accelerated mice provide a useful tool to analyse the basic mechanisms of age-related changes in bladder and urethral function.

The Effect of Cochinchina momordica Seed Extract on Gastric Acid Secretion and Morphologic Change in Aged Rat Stomach

Background/Aims

Cochinchina momordica seed extract (SK-MS10) has a gastric protective effect. We aimed to assess the effect of SK-MS10 on gastric acid secretion with morphologic changes in the aged rat.

Methods

Acid secretions were evaluated in the male F344 rats of four different ages (6-, 31-, 74-week, and 2-year). The 31-week-old rats were divided to three groups and continuously administered chow containing vehicle, SK-MS10 and lansoprazole, respectively. At the age of 74 weeks and 2 years, basal and stimulated acid was measured and the expression of mRNA and protein of H⁺-K⁺-ATPase were determined. The area of connective tissue of lamina propria was measured.

Results

Basal and stimulated gastric acid significantly decreased and connective tissue of lamina propria increased with age. The expression of mRNA and protein of H⁺-K⁺-ATPase significantly decreased with age. However, 74-week-old rats in the SK-MS10 group had higher stimulated gastric acid secretion than those in the vehicle and lansoprazole groups. In 2-year-old rats of SK-MS10 group, there was no increase of connective tissue.

Conclusions

As SK-MS10 kept the capacity of acid secretion as well as connective tissue area to comparable to young rats, it might valuable to perform further research regarding mechanism of SK-MS10 as an antiaging agent in the stomach.

Sulforaphane protects SK-N-SH cells against antipsychotic-induced oxidative stress

Adverse reactions to antipsychotic drugs (APs) have been attributed to oxidative stress. Sulforaphane (SF) is a potent antioxidant that protects against dopaminergic cell death. We examined the protective properties of SF against AP-induced oxidative stress in dopaminergic neuroblastoma cells. Human neuroblastoma SK-N-SH cells were treated with SF (0.5-5 μM), and 24 h later, haloperidol, risperidone or paliperidone (100 μM) was administered, either alone or in combination with dopamine (100 μM). To determine the antioxidant properties of SF, quinone oxidoreductase (NQO1) activity, glutathione S-transferase activity, and glutathione (GSH) levels were determined. Oxidative stress was measured by the increase in thiobarbituric acid reactive substances (TBARS) and in protein-bound quinones. Cell viability was also assessed. SF treatment increased GSH levels and induced NQO1 activity in SK-N-SH cells. Haloperidol was the only AP that increased TBARS when administered alone. When cells were cocultured with a drug in combination with dopamine, all three APs increased TBARS and protein-bound quinones and also induced neurotoxicity. In all the experimental conditions, 5 μM SF attenuated the accumulation of TBARS and protein-bound quinones and increased cell survival rates. Our results indicate that SF increases GSH levels and induces NQO1 activity and the removal of electrophilic quinones and radical oxygen species. Furthermore, SF could provide protective effects against AP-induced toxicity in dopaminergic cells.