In fish, like other organisms, the lack of balance between the production of reactive oxygen species (ROS) and antioxidant defense system (so-called oxidative stress) can cause DNA hydroxylation, p...

Oxidative Stress and Antioxidant Defense in Fish: The Implications of Probiotic, Prebiotic, and Synbiotics

Improper control on reactive oxygen species (ROS) elimination process and formation of free radicals causes tissue dysfunction. Pineal hormone melatonin is considered a potent regulator of such oxidative damage in different vertebrates. Aim of the current communication is to evaluate the levels of oxidative stress and ROS induced damage, and amelioration of oxidative status through melatonin induced activation of signaling pathways. Hepatocytes were isolated from adult Labeo rohita and exposed to H2O2 at three different doses (12.5, 25 and 50 µM) to observe peroxide induced damage in fish hepatocytes. Melatonin (25, 50 and 100 μg/ml) was administered against the highest dose of H2O2. Enzymatic and non-enzymatic antioxidants such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) was measured spectrophotometrically. Expression level of heat shock proteins (HSP70 and HSP90), HSPs-associated signaling molecules (Akt, ERK, cytosolic and nuclear NFkB), and melatonin receptor was also measured by western blotting analysis. H2O2 induced oxidative stress significantly altered (P < 0.05) MDA and GSH level, SOD and CAT activity, and up regulated HSP70 and HSP90 expression in carp hepatocytes. Signaling proteins exhibited differential modulation as revealed from their expression patterns in H2O2-exposed fish hepatocytes, in comparison with control hepatocytes. Melatonin treatment of H2O2-stressed fish hepatocytes restored basal cellular oxidative status in a dose dependent manner. Melatonin was observed to be inducer of signaling process by modulation of signaling molecules and melatonin receptor. The results suggest that exogenous melatonin at the concentration of 100 µg/ml is required to improve oxidative status of the H2O2-stressed fish hepatocytes. In H2O2 exposed hepatocytes, melatonin modulates expression of HSP70 and HSP90 that enable the hepatocytes to become stress tolerant and survive by altering the actions of ERK, Akt, cytosolic and nuclear NFkB in the signal transduction pathways. Study also confirms that melatonin could act through melatonin receptor coupled to ERK/Akt signaling pathways. This understanding of the mechanism by which melatonin regulates oxidative status in the stressed hepatocytes may initiate the development of novel strategies for hepatic disease therapy in future.

/pdf/melatonin-ameliorates-h2o2-induced-oxidative-stress-through-1b02sihtyl.pdf

Melatonin ameliorates H2O2-induced oxidative stress through modulation of Erk/Akt/NFkB pathway.

Melatonin is probably produced in all cells but is only secreted by the pineal gland. The pineal secretion of melatonin is determined by the light-dark cycle, and it is only released at night. Melatonin regulates biological rhythms via its receptors located in the suprachiasmatic nuclei of the hypothalamus. Melatonin also has strong antioxidant activities to scavenge free radicals such as reactive oxygen species (ROS). The direct free radical scavenging actions are receptor independent. ROS play an important role in reproductive function including in the ovulatory process. However, excessive ROS can also have an adverse effect on oocytes because of oxidative stress, thereby causing infertility. It is becoming clear that melatonin is located in the ovarian follicular fluid and in the oocytes themselves, which protects these cells from oxidative damage as well as having other beneficial actions in oocyte maturation, fertilization, and embryo development. Trials on humans have investigated the improvement of outcomes of assisted reproductive technology (ART), such as in vitro fertilization and embryo transfer (IVF-ET), by way of administering melatonin to patients suffering from infertility. In addition, clinical research has examined melatonin as an anti-aging molecule via its antioxidative actions, and its relationship with the aging diseases, e.g., Alzheimer's and Parkinson's disease, is also underway. Melatonin may also reduce ovarian aging, which is a major issue in assisted reproductive technology. This review explains the relationship between melatonin and human reproductive function, as well as the clinical applications expected to improve the outcomes of assisted reproductive technology such as IVF, while also discussing possibilities for melatonin in preventing ovarian aging.

/pdf/importance-of-melatonin-in-assisted-reproductive-technology-pfe1je44je.pdf

Importance of Melatonin in Assisted Reproductive Technology and Ovarian Aging

From Pauling's theories to the present, considerable understanding has been acquired of both the physiological role of vitamin C and of the impact of vitamin C supplementation on the health. Although it is well known that a balanced diet which satisfies the daily intake of vitamin C positively affects the immune system and reduces susceptibility to infections, available data do not support the theory that oral vitamin C supplements boost immunity. No current clinical recommendations support the possibility of significantly decreasing the risk of respiratory infections by using high-dose supplements of vitamin C in a well-nourished general population. Only in restricted subgroups (e.g., athletes or the military) and in subjects with a low plasma vitamin C concentration a supplementation may be justified. Furthermore, in categories at high risk of infection (i.e., the obese, diabetics, the elderly, etc.), a vitamin C supplementation can modulate inflammation, with potential positive effects on immune response to infections. The impact of an extra oral intake of vitamin C on the duration of a cold and the prevention or treatment of pneumonia is still questioned, while, based on critical illness studies, vitamin C infusion has recently been hypothesized as a treatment for COVID-19 hospitalized patients. In this review, we focused on the effects of vitamin C on immune function, summarizing the most relevant studies from the prevention and treatment of common respiratory diseases to the use of vitamin C in critical illness conditions, with the aim of clarifying its potential application during an acute SARS-CoV2 infection.

/pdf/the-long-history-of-vitamin-c-from-prevention-of-the-common-2gmkqepwm7.pdf

The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19.

Cupric nitrilotriacetate induces oxidative DNA damage and apoptosis in human leukemia HL-60 cells - Mediators of protein conformation and turnover in the cell

Fish are exposed to different heavy metals that may induce numerous physiological changes. In the present study, we examined the redox state in response to a severe stress resulting from two heavy metals (Zinc and Lead) contamination in carp Cirrhinus cirrhosus. Fish were exposed to 1/10th of LC50 of the respective metals [zinc chloride (2.72 mg/L) and lead acetate (2.53 mg/L)] for 30 days and allowed to recover for another 30 days without any metal exposure. Concentration of metals, different enzymatic and non-enzymatic antioxidant agents and expression levels of heat shock protein (HSP) 70 and 90 were measured in the liver and the kidney of fish. The lipid peroxide levels in fish tissues gradually increased with duration of treatment for both metals. After 15 days of treatment, glutathione (GSH) levels had increased, but decreased as the treatment continued for 30 days and returned to basal levels after a 30-day recovery period. Activities of all the anti-oxidant enzymes, except glutathione peroxidase, in stressed fish were significantly increased compared to those in the control at 15 days and continued till the 30th day of treatment, showing a tendency to return to basal levels after the recovery period. Expression levels of HSP70 and HSP90 gradually increased after zinc and lead treatment, respectively. The expression of HSP was higher in the liver. The results suggest that different heavy metals may have differential effects on the redox state and induction of oxidative stress in carp, in vivo.

Change in redox state and heat shock protein expression in an Indian major carp Cirrhinus cirrhosus exposed to zinc and lead.

The effects of four plant extracts on growth, sex reversal, immunological and haemato-biochemical parameters in Nile tilapia, Oreochmomis niloticus (Linnaeus, 1758)

The present study was aimed to evaluate the efficacy of Basella alba and Tribulus terrestris for induction of masculinisation in Nile tilpia. B. alba leaves and T. terrestris seeds were extracted with water, ethanol, methanol, dichloromethane, hexane and successive methanol and mixed sex juveniles of Nile tilapia were subjected to dietary treatment with the extracts at the concentration of 0.5, 1.0 and 1.5 gm/kg feed. Treatment with both the plants showed no adverse effect on general fish health. There was no significant interaction effects (P>0.05) of solvent and concentration, and solvent and plant material for percentage of males. But, significant interaction effect (P<0.05) of concentration and plant material was observed for percentage of males. Also, there was significant interaction effect (P<0.05) of solvent, concentration and plant material for percentage of males. For dietary administration of B. alba leaves, the highest percentage of males (83.2±0.7) was obtained by treatment with ethanol extract at the concentration of 1.0 gm/kg feed. For all the solvents, the highest percentage of males was observed at the concentration of 1.0 gm/kg. But, in treatment with T. terrestris seeds, the highest percentage of males (88.9±1.1) was obtained with ethanol extract at the concentration of 1.5 gm/kg feed, which was also the highest percentage of males for all the treatment categories.

/pdf/efficacy-of-basella-alba-and-tribulus-terrestris-extracts-2kyrih2g5m.pdf

Efficacy of Basella alba and Tribulus terrestris extracts for production of monosex Nile tilapia, Oreochromis niloticus -

Study was aimed to evaluate the efficacy of Mucuna pruriens seeds and Asparagus racemosus roots for induction of masculinisation in tilapia. Plant materials were extracted with water, ethanol, methanol and successive methanol and mixed sex juveniles of Nile tilapia were subjected to dietary treatment with the extracts at the concentration of 0.1, 0.15 and 0.2 g/kg feed. All treatments produced significantly higher (P<0.05) percentage of males than control. The highest percentage of males (93.79 ± 0.95) was obtained by treatment with methanol extract of M. pruriens seeds at the concentration of 0.2 g/kg feed. For A. racemosus roots also, the highest percentage of males (92.24 ± 0.13) was obtained with methanol extract at the concentration of 0.2 g/kg feed. Extracts with different solvents of both the plants showed presence of steroid/terpenoid, saponin and flavonoid. The highest percentage of phenol (658 mg of GAE/g dw) and flavonoid (11.72 mg of RE/g dw) content for M. pruriens was found in aqueous extract whereas for A. racemosus in successive (629 mg of GAE/g dw) and ethanolic extracts (22.08 mg of RE/g dw) respectively. The antiradical activity is highest in methanolic extract of Mucuna (18.265%) and ethanolic extract of Asparagus (98.522%).

Indranath Ghosal

Papers

Melatonin ameliorates H2O2-induced oxidative stress through modulation of Erk/Akt/NFkB pathway.

Change in redox state and heat shock protein expression in an Indian major carp Cirrhinus cirrhosus exposed to zinc and lead.

The effects of four plant extracts on growth, sex reversal, immunological and haemato-biochemical parameters in Nile tilapia, Oreochmomis niloticus (Linnaeus, 1758)

Efficacy of Basella alba and Tribulus terrestris extracts for production of monosex Nile tilapia, Oreochromis niloticus -

Dietary Administration of Plant Extracts for Production of Monosex Tilapia: Searching A Suitable Alternative to Synthetic Steroids in Tilapia Culture