Free Radical Load Research Articles

Apnea of Prematurity and Oxidative Stress: Potential Implications

Apnea of prematurity (AOP) occurs in 85% of neonates ≤34 weeks of gestational age. AOP is frequently associated with intermittent hypoxia (IH). This narrative review reports on the putative relationship of AOP with IH and the resulting oxidative stress (OS). Preterm infants are susceptible to OS due to an imbalance between oxidant and antioxidant systems with the excessive free radical load leading to serious morbidities that may include retinopathy of prematurity, bronchopulmonary dysplasia, and neurodevelopmental delay. Current therapeutic approaches to minimize the adverse effects of AOP and optimize oxygen delivery include noninvasive ventilation and xanthine inhibitor therapy, but these approaches have only been partially successful in decreasing the incidence of AOP and associated morbidities.

Dynamics for High-Sensitivity Detection of Free Radicals in Primary Bronchial Epithelial Cells upon Stimulation with Cigarette Smoke Extract.

Chronic obstructive pulmonary disease (COPD), the third leading cause of death worldwide, is caused by chronic exposure to toxic particles and gases, such as cigarette smoke. Free radicals, which are produced during a stress response to toxic particles, play a crucial role in disease progression. Measuring these radicals is difficult since the complex mixture of chemicals within cigarette smoke interferes with radical detection. We used a new quantum sensing technique called relaxometry to measure free radicals with nanoscale resolution on cells from COPD patients and healthy controls exposed to cigarette smoke extract (CSE) or control medium. Epithelial cells from COPD patients display a higher free radical load than those from healthy donors and are more vulnerable to CSE. We show that epithelial cells of COPD patients are more susceptible to the damaging effects of cigarette smoke, leading to increased release of free radicals.

Quantum Sensing for Real-Time Monitoring of Drug Efficacy in Synovial Fluid from Arthritis Patients.

Diamond-based T1 relaxometry is a new technique that allows nanoscale magnetic resonance measurements. Here we present its first application in patient samples. More specifically, we demonstrate that relaxometry can determine the free radical load in samples from arthritis patients. We found that we can clearly differentiate between osteoarthritis and rheumatoid arthritis patients in both the synovial fluid itself and cells derived from it. Furthermore, we tested how synovial fluid and its cells respond to piroxicam, a common nonsteroidal anti-inflammatory drug (NSAID). It is known that this drug leads to a reduction in reactive oxygen species production in fibroblast-like synoviocytes (FLS). Here, we investigated the formation of free radicals specifically. While FLS from osteoarthritis patients showed a drastic decrease in the free radical load, cells from rheumatoid arthritis retained a similar radical load after treatment. This offers a possible explanation for why piroxicam is more beneficial for patients with osteoarthritis than those with rheumatoid arthritis.

Detecting the metabolism of individual yeast mutant strain cells when aged, stressed or treated with antioxidants with diamond magnetometry

Free radicals play a key role in the ageing process. However, free radicals are small, reactive and short lived and thus challenging to measure. We utilize a new technique called diamond magnetometry for this purpose. We make use of nitrogen vacancy centers in nanodiamonds. Via a quantum effect these defects convert a magnetic resonance signal into an optical signal. While this method is increasingly popular for its unprecedented sensitivity in physics, we use this technique here for the first time to measure free radicals in living cells. Our signals are equivalent to T1 signals in conventional MRI but from nanoscale voxels from single cells with sub-cellular resolution. With this powerful tool we are able to follow free radical generation after chemically inducing stress. In addition, we can observe free radical reduction in presence of an antioxidant. We were able to clearly differentiate between mutant strains with altered metabolism. Finally, the excellent stability of our diamond particles allowed us to follow the ageing process and differentiate between young and old cells. We could confirm the expected increase of free radical load in old wild type and sod1Δ mutants. We further applied this new technique to investigate tor1Δ and pex19Δ cells. For these mutants an increased lifespan has been reported but the exact mechanism is unclear. We find a decreased free radical load in, which might offer an explanation for the increased lifespan in these cells.

Relationship Between Oxidative Stress Markers and Endothelin-1 Levels in Newborns of Different Gestational Ages.

Oxidative stress results from excessive reactive oxygen species formation and/or inadequate antioxidant defense. Premature and critically ill infants are especially susceptible due to an immature intrinsic antioxidant system that cannot fully compensate for a free radical load. Oxidative stress is also associated with endothelial dysfunction and alterations in Endothelin-1 (ET-1) signaling pathways. However, the effects of the complex interaction between oxidative stress and ET-1 in newborns are not well-understood. The objective of this pilot study was to determine the relationship between levels of common oxidative stress biomarkers [glutathione (GSH), malondialdehyde (MDA)] and ET-1 in newborns of different gestational ages. In a level IV NICU, 63 neonates were prospectively enrolled and divided into groups based on gestational age at birth: Early Preterm (24 0/7–30 6/7 weeks), Late Preterm (31 0/7–36 6/7 weeks), and Term (37 0/7–42 weeks). Umbilical cord (1.5 mL) and 24(±4) h of life (24 h) (1 mL) blood samples were collected for GSH, MDA, and ET-1 analyses. GSH, MDA, and ET-1 were determined using established methodology. Mean cord MDA levels for all age groups, Early Preterm (2.93 ± 0.08 pg/ml), Late Preterm (2.73 ± 0.15 pg/ml), and Term (2.92 ± 0.13 pg/ml), were significantly higher than those at 24 h of life (p < 0.001). Mean cord ET-1 levels were significantly higher than 24 h samples in both Early and Late Preterm groups (p < 0.05). Cord and 24 h ET-1 levels did not correlate with MDA and GSH levels at birth (r2 = 0.03, p > 0.05 and r2 = 0.001, p > 0.05, respectively) or 24 h of life (r2 = 0.001, p > 0.05 and r2 = 0.03, p > 0.05, respectively). Preterm neonates exposed to prenatal corticosteroids (1.87 ± 0.31 pg/ml) had lower cord MDA levels than non-exposed neonates (2.85 ± 0.12 pg/ml) (p < 0.05). Both cord and 24 h OS markers were significantly higher in neonates treated with oxygen therapy (p < 0.005 and p < 0.05, respectively) than those who did not receive supplemental oxygen. Oxidative stress markers (MDA and GSH) and ET-1 levels act independently. MDA is higher in cord blood than at 24 h of life regardless of gestational age. In preterm neonates, ET-1 levels are higher in umbilical cord blood compared to 24 h of life.

NAD(P)H quinone oxidoreductase (NQO1): an enzyme which needs just enough mobility, in just the right places.

NAD(P)H quinone oxidoreductase 1 (NQO1) catalyses the two electron reduction of quinones and a wide range of other organic compounds. Its physiological role is believed to be partly the reduction of free radical load in cells and the detoxification of xenobiotics. It also has non-enzymatic functions stabilising a number of cellular regulators including p53. Functionally, NQO1 is a homodimer with two active sites formed from residues from both polypeptide chains. Catalysis proceeds via a substituted enzyme mechanism involving a tightly bound FAD cofactor. Dicoumarol and some structurally related compounds act as competitive inhibitors of NQO1. There is some evidence for negative cooperativity in quinine oxidoreductases which is most likely to be mediated at least in part by alterations to the mobility of the protein. Human NQO1 is implicated in cancer. It is often over-expressed in cancer cells and as such is considered as a possible drug target. Interestingly, a common polymorphic form of human NQO1, p.P187S, is associated with an increased risk of several forms of cancer. This variant has much lower activity than the wild-type, primarily due to its substantially reduced affinity for FAD which results from lower stability. This lower stability results from inappropriate mobility of key parts of the protein. Thus, NQO1 relies on correct mobility for normal function, but inappropriate mobility results in dysfunction and may cause disease.

Comparative Assessment of Markers of Oxidative Stress in Human-milk and Plasma of Lactating Mothers

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Human-milk is a complex extracellular fluid with different biochemical composition compared with blood. The present study assessed the levels of markers of oxidative stress in human-milk and plasma of healthy lactating mothers.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Forty lactating mothers (22-36 years) volunteered to participate in this study. They were non-smokers and apparently normal nursing mothers who had normal delivery without postnatal complications. Blood and breast-milk samples were collected from the lactating mothers between 6th and 18th weeks after delivery. Total antioxidant potential (TAP), total plasma peroxides (TPP) and malondialdehyde (MDA) were determined in both human-milk and blood of the mothers using spectrophotometric methods. Oxidative stress index (OSI) was determined as the percent ratio of the TPP and TAP.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results&lt;/strong&gt;: The results showed that TAP, TPP and OSI increased significantly (p&amp;lt;0.001) in human-milk compared with the plasma. The plasma / human-milk ratios of TAP, TPP and OSI were 1:3, 1:5 and 1:2 respectively. The level of MDA was significantly (p=0.01) lower in the breast-milk, compared with the plasma. In the plasma, levels of OSI correlated significantly with TAP (r= -0.46; p= 0.015) and TPP (r=0.90; p &amp;lt;0.001) while in the breast-milk, OSI correlated significantly with only the TAP (r = -0.76; p&amp;lt;0.001).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt; It could be concluded that the higher TPP in the human milk would be beneficial against pathogens, while the bio-accumulated antioxidant molecules regulate free radical load to avert the consequences of oxidative stress in the breast tissue.&lt;/p&gt;

2.45 GHz microwave radiation induced oxidative and nitrosative stress mediated testicular apoptosis: Involvement of a p53 dependent bax-caspase-3 mediated pathway.

Deleterious effects of MW radiation on the male reproduction are well studied. Previous reports although suggest that 2.45 GHz MW irradiation induced oxidative and nitrosative stress adversely affects the male reproductive function but the detailed molecular mechanism occurring behind it has yet to be elucidated. The aim of present study was to investigate the underlying detailed pathway of the testicular apoptosis induced by free radical load and redox imbalance due to 2.45 GHz MW radiation exposure and the degree of severity along with the increased exposure duration. Twelve-week old male mice were exposed to 2.45 GHz MW radiation [continuous-wave (CW) with overall average Power density of 0.0248 mW/cm2 and overall average whole body SAR value of 0.0146 W/kg] for 2 hr/day over a period of 15, 30, and 60 days. Testicular histology, serum testosterone, ROS, NO, MDA level, activity of antioxidant enzymes, expression of pro-apoptotic proteins (p53 and Bax), anti-apoptotic proteins (Bcl-2 and Bcl-xL ), cytochrome-c, inactive/active caspase-3, and uncleaved PARP-1 were evaluated. Findings suggest that 2.45 GHz MW radiation exposure induced testicular redox imbalance not only leads to enhanced testicular apoptosis via p53 dependent Bax-caspase-3 mediated pathway, but also increases the degree of apoptotic severity in a duration dependent manner.

The Possible Role of Meditation in Myofascial Pain Syndrome: A New Hypothesis.

Background of Hypothesis:Myofascial pain syndrome (MPS) is the most common musculoskeletal pain disorder of the head and neck area. In the past, several theories were put forth to explain its origin and nature, but none proved complete. Myofascial pain responds to changing psychological states and stress, anxiety, lack of sleep, anger, depression and chronic pain are direct contributional factors. Myofascial pain syndrome may be considered as a psychosomatic disorder. There are numerous accepted palliative approaches, but of all, relaxation techniques stand out and initiate healing at the base level. In this article, the connection between mental factors, MPS and meditation are highlighted. Recent literature has shed light on the fundamental role of free radicals in the emergence of myofascial pain. The accumulating free radicals disrupt mitochondrial integrity and function, leading to sustenance and progression of MPS. Meditation on the other hand was shown to reduce free radical load and can result in clinical improvement. ‘Mindfulness’ is the working principle behind the effect of all meditations, and I emphasize that it can serve as a potential tool to reverse the neuro-architectural, neurobiological and cellular changes that occur in MPS.Conclusions:The findings described in this paper were drawn from studies on myofascial pain, fibromyalgia, similar chronic pain models and most importantly from self experience (experimentation). Till date, no hypothesis is available connecting MPS and meditation. Mechanisms linking MPS and meditation were identified, and this paper can ignite novel research in this direction.

Daily variation in antioxidant enzymes lipid peroxidation in thyroid and plasma level thyroxine and triiodothyronine levels of a tropical bird Perdicula asiatica during reproductively active and inactive phases

The aim of this work was to study the variations in the interference of neuroendocrine pineal gland and metabolically active thyroid gland in a tropical bird, Perdicula asiatica. Maximum pineal gland activity (pineal weight and melatonin level), minimum thyroid gland activity (weight, T3/T4 and thymidine kinase activity) along with less oxidative load (MDA level, SOD, CAT and ABTS activity) were observed during reproductively inactive phase (RIP) was observed. Further, a robust and significant rhythmicity was noted in melatonin levels during RIP and RAP, but no significant rhythmicity was noted in T4/T3 level by cosinor analysis. Overall, melatonin and thyroid circadian profile suggested that melatonin might be acting as an antioxidant molecule with time of the day effect in rescuing thyroid gland from free radical load in birds.

Anti-arthritogenic and cardioprotective action of hesperidin and daidzein in collagen-induced rheumatoid arthritis.

Atherosclerosis has been linked to chronic inflammatory processes. Changes in the levels of lipoproteins, especially low-density lipoprotein or its variants, as well as inflammatory markers are risk factors for the atherosclerosis. In the present study, an experimental model of rheumatoid arthritis was developed by administrating collagen suspension intradermally in the tail region of Wistar albino rats. At the same time, a suspension of hesperidin (50mg/kg body weight) and daidzein (20mg/kg body weight) was orally administrated. The compounds were given in the morning and evening for 21days. Levels of inflammatory markers in the homogenate of knee joints of experimental rats as well as plasma lipoproteins were investigated. The administration of hesperidin and daidzein caused significant (p<0.001) decrease in articular elastase activity, TNF-α, and malondialdehyde levels. Further, arthritis scoring and histological findings supported the anti-inflammatory actions of the test compounds. Interestingly, the test compounds also lowered the plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and triglyceride but increased the level of high-density lipoprotein cholesterol. The test compounds thus ameliorated the risk factors of atherosclerosis. Furthermore, antioxidant roles of hesperidin as well as daidzein were evident from decrease in free radical load demonstrated as increase in total antioxidant level in plasma of arthritic animals treated with hesperidin and daidzein. In a separate in vitro experiment, enhanced free radical scavenging activity of hesperidin was demonstrated against 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid. The anti-inflammatory, hypolipidemic, and antioxidant actions of the naturally occurring test compounds, particularly hesperidin, seem to be quite effective against rheumatoid arthritis and atherosclerosis. Thus, their consumption may be helpful in prevention or at least delaying the onset of these diseases in susceptible individuals.

Phytochemical characterization and antioxidative property of Ocimum canum: Effect of ethanolic extract of leaves and seeds on basic immunologic and metabolic status of male rats

The present study was carried out to assess the effect of ethanolic extract of leaves and seeds of Ocimum canum on the hematological parameters (hemoglobin percentage (Hb%), Red Blood Corpuscles (RBC), White Blood Corpuscles (WBC), Differential Leukocyte Counting (DLC)), free radical load on vital organs (brain, testis, liver and kidney) and lymphoid organs (bone marrow, spleen) of male rat. Chemical characterization of leaves and seeds of O. canum showed the presence of volatile oils, flavonoids, carbohydrates, phytosterols, tannins and fixed oils. An oral dose of extracted leave and seeds with 0.05mg/100g body weight daily was given to the rats for 30 days. The hematological parameter showed significant (*p<0.05) increase in Hb%, R.B.C. and basophil was noted. Whereas a significant decrease in the monocyte and eosinolphil was found after the supplementation by ethanolic extract of leaves and seeds and therefore the impact may be said as cell specific. Supplementation of the extract of leave and seeds resulted in the significant decrease of free radical load expressed in Thiobarbituric acid reactive substances (TBARS) in brain. However leaves extract was noted more effective in case of liver, kidney and testis in lowering the free radical load.

Impairment of Ovarian and Uterine Cellular Architecture, Total Protein Content: A Consequence of Lead Nitrate Induced Increased Free Radical Load

A significant decrease in weight of ovary and oviduct of female rats was noted following lead nitrate administration with a dose 80 mg/kg body weight/day for 28 days. Histomicrogaphs of ovary showed marked inhibition of follicular growth as judged by gradual decrease oocyte size, absence of theca and granulosa layer, resulting absence of graafian follicle. Oviduct showed shrinkage in lumen and damage in perimetrium cells. Increase in total protein of ovary and oviduct after lead nitrate treatment denoting changes at translational level of concern gene to prevent the normal physiology. A significant increase in the thiobarbituric acid reactive substances (TBARS) of both tissues denotes increased free radical load resulted in the damage of cellular architecture. Findings, suggest that lead entering to the biological system via environment and other widely used industrial product may interfere with the normal reproductive physiology and folliculogenesis could be one of the cause of female infertility.

Melatonin Attenuates Free Radical Load and Reverses Histologic Architect and Hormone Profile Alteration in Female Rat: An In vivo Study of Pathogenesis of Letrozole Induced Poly Cystic Ovary

Objectives: The present study was designed and conducted for obtaining information about the role of melatonin (Mel) in pathophysiology of polycystic cystic ovarian syndrome (PCOS) which generally leads to infertility in human females.Methodology: Letrozole, a non-steroidal aromatase inhibitor supplemented (1 mg/100 g/body weight/day for 28 days) for induction of (PCOS). Treatment of exogenous melatonin (200 μg/100 g/body weight/day) was given to PCO and normal rats. After completion of experiment gravimetric analysis, Lipid peroxidation (LPO) in terms of thiobarbituric acid reactive substance (TBARS), histological slide preparation following hemotoxylene-eosin (HE) double staining method for ovarian tissue was done and results were documented. Hormonal assay estrogen (E), progesterone (P), and Melatonin (Mel), luteinizing hormone (LH) and follicle stimulating hormone (FSH) was performed using ELISA kit.Major findings: Letrozole induced PCOS exhibited increase in ovarian weight, lipid peroxidation level (LPO). Histopathology of PCO rats showed sub-capsicular cysts and capsicular thickening. Circulatory hormone profiles showed a significant decrease in plasma level of E, P, Mel. Plasma testosterone (T) level was noted significantly high whiles an unsteady ratio of LH) and FSH in PCOS rats. Melatonin treatment to the PCO rats showed recovery in ovarian weight, significant decrease in lipid per oxidation (LPO), withdrawal of presence of cyst from ovarian histology, reversal of plasma circulatory hormone profile to the control group of rats.Conclusion: The finding update about similarity of ovarian cysts in rats to that observed in human PCOS and their regression following exogenously melatonin administration. The present findings may indicate and novel therapeutic approach based on the modulation of pathogenicity of PCOS in female rats through melatonin to improve the functional ovarian physiology as a possible future molecule among human females to treat the infertility. Such clinical trials may really prove to be highly beneficial for women with PCOS.

Melatonin improves ultraviolet B-induced oxidative damage and inflammatory conditions in cutaneous tissue of a diurnal Indian palm squirrel Funambulus pennanti.

Skin is exposed to various abiotic and biotic factors. Solar radiation, of which ultraviolet (UV) rays are a principle component, increases the free radical load, and the accumulation of reactive oxygen species (ROS) causes lipid peroxidation, DNA damage and apoptosis, and is also associated with inflammatory responses recruiting molecules [nuclear factor (NF)-κB, interleukin (IL)-6] that can potentially further aggravate the damaged milieu of the cells. One of the potent causes of skin cancers is exposure to UV rays. UV radiation generates a wide range of biological responses such as adaptive, inflammatory and immunological reactions in the skin. To examine the effects of pretreatment with melatonin on UVB (290-320nm) radiation-mediated damage to the skin of a diurnal rodent Funambulus pennanti. The UVB radiation (1·5J cm(-2) for 30min daily on the shaved abdominal area) for 4days caused a significant increase in the lipid peroxidation products (thiobarbituric acid reactive substances, TBARS) and decreased the activity of the antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) of the skin. Pretreatment with melatonin (100μg100g(-1) bodyweight subcutaneously) improved the damage induced by UVB radiation on the skin and might act via a receptor-independent mechanism. No significant effect of melatonin pretreatment was found on the expression pattern of MT1 (melatonin membrane receptor) and RORα (nuclear retinoic orphan receptor alpha), which suggests a receptor-independent action. However, NF-κB and inflammatory cytokine IL-6 levels were downregulated in the squirrels pretreated with melatonin before the UVB radiation. UVB radiation induced oxidative stress in the skin culminating in an inflammatory response. The action of melatonin in protecting the skin from oxidative damage occurs in a receptor-independent manner by lowering the oxidative damage and inflammatory response. On the other hand, melatonin decreased the expression of NF-κB and the circulating proinflammatory cytokine IL-6, suggesting an anti-inflammatory action in protecting the skin from UVB radiation.

UVB irradiation severely induces systemic tissue injury by augmenting oxidative load in a tropical rodent: Efficacy of melatonin as an antioxidant

Tropical animals are regularly exposed to solar UV radiation. The generation and accumulation of free radicals as a result of UVB incidence causes tissue damage. In the present study we report that the irradiation of Funambulus pennanti by 1.5J/cm2 of UVB caused significant oxidative damage to the spleen. The systemic immunity suffered collateral damage as depicted by results of total leukocyte count (TLC) while an increase in the thiobarbituric acid reactive substances (TBARS) and decline in the activities of enzymes superoxide dismutase (SOD), Glutathione peroxidase (GSH-Px) and Catalase (CAT) denoted oxidative tissue damage. Melatonin the indole-amine with known antioxidative properties when administered subcutaneously (s.c 100μg/100 gm body weight), before the UVB irradiation recovered the damages caused by UVB radiation in the spleen. The action of melatonin was direct and might have involved its membrane receptor (MT1) as well as nuclear receptor (RORα) indicating the fact that the mode of action of melatonin in ameliorating UVB radiation induced free radical load may be receptor mediated. Our study hence reports for the first time that UVB radiation incurred oxidative damage to the spleen and suppressed the normal tissue functions. This UVB mitigated oxidative stress was recovered by the free radical scavenging and anti-apoptotic functions of melatonin when administered prior to UVB irradiation.

Beneficial effect of extracts of Premna integrifolia root on human leucocytes and erythrocytes against hydrogen peroxide induced oxidative damage

Background: Oxidative damage as a result of an increase in the free radical load and/or decrease in the efficiency of the antioxidant systems has been implicated in many human diseases. Premna integrifolia (Verbenaceae) is an important woody, medicinal plant and has a prominent place in Ayurvedha, Siddha and Unani system of medicines. Traditionally, it has been used for various antioxidant related disorders. Objective: The objective of the present study was to evaluate the beneficial effect of extracts of P. integrifolia root on human leucocytes and erythrocytes against hydrogen peroxide (H 2 O 2 ) induced oxidative damage. Materials and Methods: Chloroform:methanol (1:1) extract of P. integrifolia (CMEPI) and aqueous extract of P. integrifolia roots were used to accessed catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH) and lipid peroxidation (LPO) levels in H 2 O 2 induced oxidative damage. Results: Results of the present study revealed that, there was an increase in the CAT, SOD, GPx and reduction of the GSH and LPO levels in H 2 O 2 group compared with the control. P. integrifolia root extract treated groups showed the reduction of CAT, SOD, GPx and increased in the GSH and LPO levels as compared with H 2 O 2 group. CMEPI was found to be more effective than aqueous. Conclusion: The present study suggests that, extracts of P. integrifolia root possess beneficial effect on human leucocytes and erythrocytes against H 2 O 2 induced oxidative damage which has substantiated their use in ethnomedicine as an antioxidant. Observed effect can be attributed due to the flavonoid and phenol contents in the plant. Furthermore, in-vitro and in-vivo studies are needed to explore its effects on antioxidant system of the body for proving its clinical safety, reliability and efficacy.

Hesperidin inhibits collagen-induced arthritis possibly through suppression of free radical load and reduction in neutrophil activation and infiltration

Rheumatoid arthritis is a chronic inflammatory disease characterized by the destruction of articular cartilage and bone in a chronic phase. Pathology of rheumatoid arthritis suggests autoimmunity linked to inflammation. In our study, rheumatoid arthritis was induced in Wistar rats by intradermal injections of 100 μl of emulsion containing bovine type II collagen in complete Freund's adjuvant at the base of the tail. Disease developed about 13 ± 1 days after immunization and treatment with hesperidin (HES) at a dose of 160 mg kg(-1) body weight was given after onset of disease daily until 20th day. The effect of treatment in the rats was monitored by clinical scoring, biochemical parameters and histological evaluations in joints. A steady increase in the articular elastase, nitric oxide and lipid peroxidation was observed in joints of arthritic rats as compared to control, whereas a significant decrease in reduced glutathione, superoxide dismutase activity and catalase was observed in collagen-induced arthritis rats as compared to control group. The results from the present work indicate that the treatment with hesperidin was effective in bringing about significant changes on all the parameters studied in collagen-induced arthritis rats. These data confirm that erosive destruction of the joint cartilage in collagen-induced arthritis is due free radicals released by activated neutrophils and produced by other biochemical pathways. In the present study, an attempt has been made to amelioration of the disease process by a natural product. These results suggest that oral administration of HES could be effective for treating human RA patients.

Daily variation in antioxidant enzymes and lipid peroxidation in lungs of a tropical bird Perdicula asiatica: Role of melatonin and nuclear receptor RORα

The wild animals are exposed in nature to more oxidative stress than any laboratory animals. Studies on oxidative stress of brain, liver and kidney are quite common while very less reports are available on respiratory system when it is the most susceptible organ to various stressors. We checked the oxidative stress of lung tissue of a wild seasonally breeding bird Perdicula asiatica by noting down the daily variation in antioxidant enzymes (superoxide dismutase and catalase) levels, lipid peroxidation in terms of malondialdehyde level and total antioxidant status during reproductively active (RAP) and inactive phase (RIP). On the other hand melatonin has been accepted as free radical scavenger acting via receptor (nuclear receptor) or non receptor pathway. To pin point the role of melatonin in regulation of antioxidant enzymes via non receptor mediated pathway in lungs of bird, we checked variation in the nuclear melatonin receptor RORα. Antioxidant enzymes (superoxide dismutase and catalase) exhibited a marked 24h rhythm in lungs being high during night time and coincided almost with the peak of melatonin and total antioxidant status where as malondialdehyde level and nuclear receptor RORα showed inverse relationship with all the above mentioned parameters. These findings suggest that melatonin might be acting as an antioxidant for the free radical load of lung tissue of a tropical bird P. asiatica and its action might be via nuclear receptor RORα.

Age dependent expression of melatonin membrane receptor (MT1, MT2) and its role in regulation of nitrosative stress in tropical rodent Funambulus pennanti

Age-dependent declining level of melatonin induces free radical load and thereby deteriorates immune function. However, reports are lacking about age-dependent melatonin membrane receptor (MT1 & MT2) expression, their role in regulation of reactive nitrogen species (RNS) and eventually how they affect immunity of a tropical rodent F. pennanti. We checked MT1R, MT2R and iNOS expression in lymphoid organs of young middle and old aged squirrels. Nitrite and nitrate ion concentration (NOx) in lymphoid organs, testes and plasma, lymphocyte proliferation and IL-2 level was recorded. Age-dependent decrease in MT1 and MT2 receptor expression, lymphocyte proliferation, IL-2 level and increased RNS in lymphoid organs, testes and plasma was observed with decreased circulatory melatonin. Androgen and AR expression was increased in middle-aged while declined in old-aged squirrels. Present study suggests that age associated immunosenescence is consequence of increased RNS which might have important relationship with melatonin membrane receptors in F. pennanti.