Effect of methanol intoxication on spcific immune functions of albino rats

The impact of non-caloric artificial sweetener aspartame on female reproductive system in mice model

BACKGROUND

Artificial sweeteners, used as sugar substitutes have found their ways into almost all the food items due to the notion that they are non-caloric. Aspartame is used in numerous food products throughout the world. The primary users of aspartame include diabetics and calorie conscious people who intend to limit their calorie intake.

METHODS

Female Swiss albino mice were divided into three groups (12 mice each) for the duration of 30 and 60 days consecutively. The treatment groups received 40 mg/kg b. w. aspartame orally. Hormone assays using ELISA and tissue histopathology have been performed along with the fertility assay to access the treatment outcomeon the fertility of treated mice in comparison to controls.

RESULTS

Present study reports that female mice treated with aspartame for 30 and 60 days showed significant reduction in body weight, relative organ weight of (liver and kidney) and gonadosomatic index. These changes were more significantly recorded in 60 days treatment group. Aspartame treated animals for 30 and 60 days showed duration-dependent decrease gonandotropins (follicle stimulating hormone and luteinizing hormone), and steroids (estradiol and progesterone). Moreover, severe histopathological changes, reduction in number of growing follicles, degenerative changes in follicular structure, corona radiata and zonagranulosa were also observed. Besides, histomorphological changes were also observed in the uterine structure including atrophic uterine endometrial glands, contracted endometrial lining, disruption of the endometrial structure and the shapes of blood vessels were also altered.

CONCLUSION

Non-nutritive artificial sweeteners including aspartame negatively impact the function of ovaries and feedback mechanism of reproductive hormones by affecting the hypothalamic-pituitary-gonadal axis. In light of present findings the aspartame negatively impacted the reproductive system of female mice. More studies are required to identify the molecular mechanism and the pathways involved.

Analgesic effects of main indole alkaloid of kratom, mitragynine in acute pain animal model

Mitragynine exerts its analgesic effect mainly via opioid receptors activation. Additionally, the effect may be mediated via mitragynine's anti-inflammatory property and non-opioid receptor pain pathways, namely through the TRPV1 receptor. No studies identify hitherto, hence, the current study aimed to investigate the mitragynine's analgesic effect via the anti-inflammatory property, non-opioid receptor (TRPV1) and the effective dose (ED) to alleviate pain. Male and female Sprague Dawley rats were pre-treated intraperitoneally with either mitragynine (1, 5, 10, 13, 15 or 30 mg/kg), vehicle, or indomethacin (1 mg/kg) 30 min before inducing inflammatory pain using acetic acid. The writhes and pain-related withdrawal behaviour occurrence were counted within a 1-h duration. Percentage of writhes inhibition, pain-related withdrawal behaviour aggregate, ED50 and ED95 were determined. The body temperature was recorded and TRPV1 expression in the rats' brains was measured. Mitragynine (except 1 mg/kg) significantly reduced the number of writhes compared with the vehicle administered group. Mitragynine (30 mg/kg) demonstrated 99.5% inhibition of writhing behaviour and low withdrawal behaviour score compared with vehicle and indomethacin and successfully blocked the hypothermia induced by acetic acid. The overall ED50 and ED95 values of mitragynine were 3.62 and 20.84 mg/kg, respectively. The percentage of writhing inhibition and withdrawal behaviour were similar in both genders. Mitragynine (15 and 30 mg/kg) significantly reduced the TRPV1 expression in the brain of the rats. Mitragynine alleviated pain-like behaviour and showed analgesic effects via anti-inflammatory and non-opioid receptor pathways. The findings also suggest that mitragynine might regulate some physiological functions of the rat.

Acute and chronic blood serum proteome changes in patients with methanol poisoning

Twenty-four blood serum samples from patients with acute methanol poisoning (M) from the mass methanol poisoning outbreak in the Czech Republic in 2012 were compared with 46 patient samples taken four years after poisoning (S) (overlap of 10 people with group M) and with a control group (C) of 24 samples of patients with a similar proportion of chronic alcohol abuse. When comparing any two groups, tens to hundreds of proteins with a significant change in concentration were identified. Fifteen proteins showed significant changes when compared between any two groups. The group with acute methanol poisoning showed significant changes in protein concentrations for at least 64 proteins compared to the other groups. Among the most important identified proteins closely related to intoxication are mainly those involved in blood coagulation, metabolism of vitamin A (increased retinol-binding protein), immune response (e.g., increased complement factor I, complement factors C3 and C5), and lipid transport (increased apolipoprotein A I, apolipoprotein A II, adiponectin). For blood coagulation, the most affected proteins with significant changes in the methanol poisoning group were von Willebrand factor, carboxypeptidase N, alpha-2-antiplasmin (all increased), inter-alpha-trypsin inhibitor heavy chain H4, kininogen-1, plasma serine protease inhibitor, plasminogen (all decreased). However, heparin administration used for the methanol poisoning group could have interfered with some of the changes in their concentrations. Data are available via ProteomeXchange with the identifier PXD035726.

Methanol-induced optic neuropathy: a still-present problem

Methanol-induced optic neuropathy (Me-ION) is a serious condition that may result in long-term or irreversible visual impairment or even blindness secondary to damage and loss of function of the optic nerve and retina. Me-ION shows a tendency to occur as mass poisonings around the world with a clear predilection for poor societies in developing countries. The main mechanism underlying the molecular basis of Me-ION is the inhibition of the mitochondrial oxidative phosphorylation process through the binding of the toxic metabolite of methanol—formic acid—with the key enzyme of this process—cytochrome c oxidase. However, other mechanisms, including damage to the eye tissues by oxidative stress causing the intensification of the oxidative peroxidation process with the formation of cytotoxic compounds, as well as an increase in the synthesis of pro-inflammatory cytokines and influence on the expression of key proteins responsible for maintaining cell homeostasis, also play an important role in the pathogenesis of Me-ION. Histopathological changes in the eye tissues are mainly manifested as the degeneration of axons and glial cells of the optic nerve, often with accompanying damage of the retina that may involve all its layers. Despite the development of therapeutic approaches, persistent visual sequelae are seen in 30–40% of survivors. Thus, Me-ION continues to be an important problem for healthcare systems worldwide.

Prenatal exposure to methanol as a dopamine system sensitization model in C57BL/6J mice

AIMS

In this study, the effects of prenatal exposure to methanol (MeOH) on the nigrostriatal dopamine (NSDA) system were examined to determine if the interaction could sensitize this system, and serve as an underpinning for Parkinson's disease (PD) like changes that occur later in life. Methanol was studied because its toxicity resembles the symptoms of PD and the symptoms are relieved by L-dopa meaning that MeOH targets the NSDA system. Since fermentation and wood combustion are major sources for MeOH, the incidence of human encounters with MeOH is high. As a superior solvent and the precursor for formaldehyde, MeOH has a powerful and sometimes, irreversible impact on chemical processes, such as cross-linking proteins and nucleic acids. It may cause subthreshold changes that sensitizes the NSDA system to PD, that occur during aging.

MAIN METHODS

To study the prenatal effects of MeOH, pregnant C57BL/6J mice were administered 40 mg/kg MeOH by oral gavage during gestation days 8-12, twice daily. Twelve weeks after birth, behavior impairments were recorded. The striatum was dissected for the determination of tyrosine hydroxylase (TH), L-aromatic amino acid decarboxylase (LAAD), α-synuclein and levels of dopamine (DA) and its metabolites.

KEY FINDINGS

MeOH reduced striatal TH and LAAD protein by 47% and 57% respectively and DA by 32%.

SIGNIFICANCE

The results mean that in utero exposure to toxins similar to MeOH could sensitize the striatal system to changes that cause PD. This study may help identify strategies to block this type of in utero toxicity.

Effect of hemodialysis and diet on the exhaled breath methanol concentration in patients with ESRD

OBJECTIVES

End-stage renal disease (ESRD) causes accumulation of nitrogenous waste products and acid-base, mineral, fluid, and electrolyte disorders, which are partially corrected by hemodialysis (HD). While the effects of ESRD and dialysis on body fluid composition are well known, the effects on composition of expired breath are uncertain. Methanol is produced from unabsorbable complex carbohydrates by the colonic microbiome. Dietary restrictions of fruits and vegetables aimed at limiting potassium intake lower the intake of dietary fibers; the reduced fiber intake can in turn reduce production of methanol and its appearance in the exhaled breath. In this study, we investigated the inter- and intradialytic changes in the breath methanol levels.

DESIGN AND METHOD

Ten ESRD patients were studied during HD procedures at 3- and 2-day interdialytic intervals. On each occasion, 20 exhaled breath and room air samples were collected using evacuated canisters. Ten age-matched normal subjects served as controls. The samples were analyzed on a unique 6-column/detector gas chromatography system.

RESULTS

Seven ESRD patients consuming renal diet had lower methanol concentration (90 ± 29 ppbv) than the 3 patients consuming high-fiber diet (340 ± 48 ppbv, P ≤ .0006) and the 10 controls consuming unrestricted diets (202 ± 80 ppbv, P ≤ .001). HD significantly lowered breath methanol (60% ± 12%), paralleling the fall in serum urea concentration (70% ± 6%). The predialysis methanol concentration was slightly higher at 3-day than the 2-day interdialytic intervals.

CONCLUSION

Dietary restriction of fruits and vegetables lowers methanol production by the gut microbial flora in ESRD patients. Perhaps, methanol is a reliable breath biomarker to monitor individuals' daily fiber intake. Breath methanol is dramatically reduced by HD, reflecting its efficient removal.

Sugar substitutes: Health controversy over perceived benefits

Sugar is an inseparable part of the food we consume. But too much sugar is not ideal for our teeth and waistline. There have been some controversial suggestions that excessive sugar may play an important role in certain degenerative diseases. So artificial sweeteners or artificially sweetened products continue to attract consumers. A sugar substitute (artificial sweetener) is a food additive that duplicates the effect of sugar in taste, but usually has less food energy. Besides its benefits, animal studies have convincingly proven that artificial sweeteners cause weight gain, brain tumors, bladder cancer and many other health hazards. Some kind of health related side effects including carcinogenicity are also noted in humans. A large number of studies have been carried out on these substances with conclusions ranging from "safe under all conditions" to "unsafe at any dose". Scientists are divided in their views on the issue of artificial sweetener safety. In scientific as well as in lay publications, supporting studies are often widely referenced while the opposing results are de-emphasized or dismissed. So this review aims to explore the health controversy over perceived benefits of sugar substitutes.

Methanol induces a discrete transcriptional dysregulation that leads to cytokine overproduction in activated lymphocytes

Methanol is an important cause of acute alcohol intoxication; it is ubiquitously present at home and in the workplace. Although the existing literature provides a reasonable insight into the immunological impact of ethanol and to a much lesser extent of isopropanol, much less data are available on methanol. We hypothesized on structural grounds that methanol would share the immunosuppressive properties of the two other short-chain alcohols. We report here that methanol increases the proliferative capacity of human T lymphocytes and synergizes with the activating stimuli to augment cytokine production. The cytokine upregulation was observed in vitro at methanol concentrations as low as 0.08% (25mM) as measured by interleukin-2, interferon-γ, and tumor necrosis factor-α release in T cells. Methanol did not affect the antigen receptor-mediated early signaling but promoted a selective and differential activation of the nuclear factor of activated T cells family of transcription factors. These results were further substantiated in a mouse model of acute methanol intoxication in which there was an augmented release of proinflammatory cytokines in the serum in response to the staphylococcal enterotoxin B. Our results suggest that methanol has a discrete immunological footprint of broad significance given the exposure of the general population to this multipurpose solvent.