Environmental pollution affects genetic diversity in wild bird populations

Many common environmental pollutants, together with nuclear radiation, are recognized as genotoxic. There is, however, very little information on pollution-related genetic effects on free-living animal populations, especially in terrestrial ecosystems. We investigated whether genetic diversity in two small insectivorous passerines, the great tit (Parus major) and the pied flycatcher (Ficedula hypoleuca), was changed near point sources of heavy metals (two copper smelters) or radioactive isotopes (nuclear material reprocessing plant). We measured concentration of heavy metals and nucleotide diversity in mitochondrial DNA in feather samples taken from nestlings in multiple polluted areas and at control sites. In both species, heavy metal concentrations - especially of arsenic - were increased in feathers collected at smelter sites. The P. major population living near a smelter showed significantly higher nucleotide diversity than a control population in an unpolluted site, suggesting increased mutation rates in a polluted environment. On the contrary, F. hypoleuca showed reduced nucleotide diversity at both smelter sites but increased nucleotide diversity near the source of radioactivity. Our results show that heavy metal pollution and low level nuclear radiation affect the nucleotide diversity in two free-living insectivorous passerines. We suggest that the different response in these two species may be due to their different ability to handle toxic compounds in the body.     

Growth and mortality of nestling great tits (Parus major) and pied flycatchers (Ficedula hypoleuca) in a heavy metal pollution gradient

We studied nestling growth, growth abnormalities, mortality and breeding success of two hole-nesting passerines, the great tit (Parus major) and the pied fly-catcher (Ficedula hypoleuca), at 14 study sites around a copper smelter complex in Harjavalta, south-west Finland in 1991–1993. The main pollutants in the area are heavy metals and sulphuric oxides. Exposure of birds to heavy metals was shown by measuring their faecal concentrations. Copper, nickel and lead contents of nestling faeces were high near the factory and decreased with distance away from the pollution source. F. hypoleuca nestlings suffered high mortality very close to the factory complex, but did relatively well at all other sites. Breeding success of P. major was below background levels up to 3–4 km from the pollution source and nestlings grew poorly close to the factory. Growth abnormalities of legs and wings in F. hypoleuca nestlings were significantly more common near the factory than farther away. In contrast, F. hypoleuca nestlings grew equally well at all distances. The poor breeding success of F. hypoleuca close to the factory complex is probably related to the high amount of heavy metals in its diet, and low availability of calcium-rich food items may enhance this effect. We suggest that the poor breeding success of P. major is related to habitat changes that have taken place around the factory. The different responses of these two bird species are probably due to their different diet. Our results show convincingly that species-specific differences in response should be carefully considered when planning schemes for air pollution monitoring.     

The effects of diet quality and quantity on plumage colour and growth of great tit Parus major nestlings: a food manipulation experiment along a pollution gradient

The yellow carotenoid-based plumage coloration of great tit Parus major nestlings is found to be paler in polluted and urban environments. Because carotenoid pigmentation is often considered to be a condition dependent trait in birds we wanted to find out whether food-limitation and poor nestling condition could explain the pale plumage colour in a polluted area. P. major nestlings were supplemented with variable diets along a well known heavy metal pollution gradient around a copper smelter: two food treatments with carotenoids, one food treatment with little carotenoid and one unsupplemented control. Our field experiment showed that nestlings in the polluted area grew better with carotenoid rich diets, while such effect was not found in the unpolluted area. Nestlings showed higher plasma carotenoid (lutein) levels and higher plumage carotenoid chroma values in the unpolluted area than in the polluted area. However, plasma lutein levels or plumage colour were not associated with heavy metal levels in nestling faeces (a proxy for dietary exposure). Our results provide only weak evidence for carotenoid-based colouration to be condition-dependent in great tit nestlings as we found a positive relationship between body mass and carotenoid chroma in the non-supplemented control group only. The positive relationship between body mass and plumage colour intensity is more likely to be produced by the fact that good availability of caterpillars, an important food source for P. major, also means a good availability of carotenoids to nestlings. Our results suggest that main reason for pale nestling plumage in the polluted area is lower quality invertebrate food, and not nutrition-related oxidative stress.     

Disruption of the melatonin rhythm in wild and farmed fish: a consequence of prolonged thyroxine administration and calcium depletion

Recent studies suggest that the pineal gland and its major product melatonin (N‐acetyl‐5‐methoxytryptamine: Mel) play a role in integration of various neural and endocrine functions. Observations indicate that Mel as a signal of photoperiod regulates a number of biological phenomena, including reproduction, day/night activity and many other physiological events associated with daily or seasonal rhythms in vertebrates, including fish. Mel has also been found to be a highly effective preventive antioxidant and free radical scavenger, protecting organism from oxidative damage. In all species examined, plasma melatonin concentration shows a diurnal rhythm, with the highest levels during the night. Our studies are focused on the cues affecting Mel synthesis capacity in wild and farmed fish. The Mel rhythm in fish can be disrupted by fluctuations in surrounding calcium concentration or by prolonged thyroxine (T4) exposure. Physiological depletion of plasma ionized calcium may limit the capacity of Mel night production in two fish species, farmed rainbow trout and wild flounder. Prolonged (2 week) exposure to high level of exogenous thyroxine (T4) results in reduced night‐time plasma Mel levels, and may thus inhibit the melatonin‐related time‐keeping system in juvenile salmon. Disruption of the daily Mel rhythm implies a reduced ability of organisms to respond properly to environmental signals, and may be a useful indicator of disturbance in physiological functions.     

Air pollution fades the plumage of the Great Tit

1. Great Tits ( Parus major ) derive the carotenoid pigments for their yellow plumage via the prey items in their diet. Air pollution is known to affect the abundance of many forest insects, e.g. green caterpillars, which are an important source of food and pigments for tits. This study investigates whether air pollutants indirectly affected the intensity of the yellow colour in P. major plumage via the reduced access to carotenoid sources.
2. The intensity of the yellow colour in the plumage of P. major nestlings was scored and the relative abundance of green herbivorous larvae in territories around a polluting copper smelter in SW Finland was simultaneously measured.
3. Both the intensity of yellow colour in nestling plumage and caterpillar abundance increased with increasing distance from the pollution source. The colour intensity correlated significantly with the density of green herbivorous larvae in a territory.
4. Parus major nestlings were significantly heavier at distant sites than close to the pollution source which suggests that the future survival probability of pale nestlings may be lowered.
5. Young birds, after their first moult, were studied for the relationships between condition, size and plumage colour by the means of ptilochronology. The plumage colour intensity did not correlate with the size corrected width of the growth bars in fifth rectrix (condition at moult) but was correlated positively with the length of the rectrix (size).
6. The implications of colour change for survival and mate choice are discussed.     

Melatonin and biological rhythms

Circadian and seasonal rhythms are a fundamental feature of all living organisms. The functional mechanism involved is built around internal biological clock(s) and the hormone melatonin (Mel) is one of its critical components. Although numerous other sources have been identified (retina, harderian gland, gut), in vertebrates Mel is primarily produced by the pineal gland during the dark period of the light-dark cycle. This rhythmic Mel is generated directly by circadian clock(s). The Mel rhythm is thus an important efferent hormonal signal from the clock. The periodic secretion of Mel might thus be used as a circadian mediator of a system that can 'read' the message.The duration of the nocturnal Mel production is directly proportional to the length of the dark period. It is through these changes in duration that the brain integrates the photoperiodic information. In essence, the Mel rhythm appears to be an endocrine code of the environmental light-dark cycle conveying photic information that is used by organisms for both circadian and seasonal temporal organization. The major question arising from this effect of Mel concerns it precise mechanism of action. From the data reported in the present minireview, it appears that the photoneuroendocrine mechanism is not fundamentally different in vertebrates at least as far as the role of Mel is concerned.     

Pollution related effects on immune function and stress in a free-living population of pied flycatcher Ficedula hypoleuca

We investigated whether exposure to heavy metal pollution affected the immune function of individuals in a free living population of a small insectivorous passerine bird, the pied flycatcher Ficedula hypoleuca . We measured humoral immune responses in two study areas: a polluted area in the vicinity of a copper smelter and a control area far from the smelter. Plasma corticosterone level and blood heterophil/lymphocyte ratio (H/L) were used as more general physiological measures of stress. The immune response of F. hypoleuca was not suppressed by pollution stress. In contrast, we found that F. hypoleuca males showed stronger humoral immune responses to a novel antigen (tetanus toxoid) in the polluted environment than in the unpolluted one. After the immunization of males, numbers of lymphocytes rose significantly more in the polluted area, leading to a smaller H/L ratio than in males from the control area. Females showed no pollution related effects on their immune responses. Corticosterone levels of males and nestlings were not related to pollution levels. Nestlings showed somewhat higher H/L ratios and lower fledging success in the polluted area, both factors indicating increased stress levels in a polluted area. Our results suggest that humoral immune response of male F. hypoleuca may be enhanced under moderate levels of heavy metal pollution. Enhanced immune function may, however, also be costly for birds and the higher humoral immune responses in polluted areas may thus have negative effects on the birds' breeding performance and survival.     

Pollution-related changes in oxidative stress and antioxidant defense profile in the blood of white stork Ciconia ciconia chicks from different regions of Poland

Changes in the lipid peroxidation and oxidatively modified protein levels as well as the antioxidant defense system in the blood of white stork (Ciconia ciconia) chicks were analyzed during their development in nests in polluted and control environments. The control, relatively pure, environment was the village of K?opot, with no industrial plants within a radius of 150 km. Blood samples were also collected in two polluted areas, including (1) the suburban village of Czarnowo, located 20 km from the city of Zielona Góra (southwestern Poland) and (2) an area near the town of G?ogów, where a large copper smelter is situated. The effects of various ecological threats from different environments tended to initiate oxidative stress and decrease total antioxidant capacity. The initiation of lipid peroxidation and increases in the levels of carbonyl derivatives of oxidative amino acids were observed in the plasma of chicks from polluted areas. Plasma catalase and the selenium-dependent glutathione peroxidase activities of erythrocytes were significantly higher in chicks from polluted areas than in those from control areas. Oxidative stress and components of the antioxidant defense system, especially glutathione peroxidase activity, can be used as indicators of oxidative stress, which was found to be greater in the polluted areas (near the G?ogów copper smelter). Research into oxidative stress biomarkers can aid assessments of the conditions of birds, and points to a positive association with miscellaneous environmental loads.     

The effect of heavy metal accumulation on metallothionein content in selected tissues of bank voles and yellow-necked mice caught near a steelworks and zinc smelter

The effect of cadmium, zinc, and copper accumulation on metallothionein content in the selected tissues of bank voles and yellow-necked mice trapped near the Sendzimir Steelworks in Krakow and the zinc smelter in Bukowno were analysed. The Borecka Forest was chosen as a control area. The highest cadmium concentration, 32.98 microg g(-1) dry weight, was detected in the kidneys of the bank voles caught in the Bukowno area. Zinc and copper concentrations in the tissues did not exceed the critical values. Metallothionein content in the liver and kidneys was associated with heavy metal accumulation in the tissues. The highest content of sulphydryl groups was detected in the livers of the bank voles trapped within the neighbourhood of the zinc smelter in Bukowno. The highest level of disulphide bonds was found in the kidneys of the bank voles from the same area.     

Thymidine kinase and adenosine kinase activities in homogenates of thyroid lobes in hemithyroidectomized rats; effects of melatonin in vitro

OBJECTIVES: Thymidine kinase (TK, EC 2.7.1.21) is a part of the pyrimidine salvage pathway, involved in DNA synthesis. In turn, adenosine kinase (AK, EC 2.7.1.20) functions as a part of the purine metabolic pathway, involved in DNA synthesis. Melatonin (Mel) is an indoleamine which is known to inhibit growth processes in the thyroid gland and also in other endocrine and non-endocrine tissues. The aim of our study was to examine TK and AK activities in homogenates of the rat thyroid lobes remaining after contralateral hemithyroidectomy (hemiTx); additionally, incubations with Mel (10(-6), 10(-9), and 10(-12) M) were performed. METHODS: The experiment was performed on young male Wistar rats (6-week old). The enzyme activities were measured by ascending chromatography and expressed as the amounts of radioactive reaction products of the phosphorylation of dThd (for TK) and of dAdo (for AK). RESULTS: 1. HemiTx increased TK activity in homogenates of the remaining thyroid lobe; 2. Mel increased TK activity in all the groups (intact, sham-operated- and hemiTx-rats), except for the concentrations of 10(-9) and 10(-12) M in the hemiTx-rats, in which the increasing effects of Mel on TK activity reached the borderline statistical significance only; 3. Mel increased the AK activity in intact and in shamTx animals; 4. No statistically significant changes were found in AK activity following Mel in vitro in the incubated remaining thyroid lobes, collected from hemiTx-rats.     

杂色山雀亲代喂食与子代乞食间的行为

在育雏期,晚成鸟的子代一般都是由双亲共同来抚育,子代为了更好地存活,会用自己的方式竞争获得更多的食物和更好的生存空间,同时亲代也会根据子代的乞食信号来分配食物。2011年3～7月采用针孔摄像技术录制了杂色山雀(Parus varius)育雏期巢内亲代与子代间的行为,统计了亲鸟站位、雏鸟站位、雏鸟乞食强度及亲鸟的喂食情况等数据。分析结果表明:(1)雌雄亲鸟在巢中的站位各有特点,雄鸟在整个育雏期都喜欢站在距离巢口较近的位置;雌鸟站位不太固定,前期离巢口相对较远,中期和后期离巢口相对较近;(2)雏鸟离亲鸟越近,乞食强度越大,获得食物的机会就越多;离亲鸟越远的雏鸟越不爱乞食,所以站位对雏鸟的食物获得影响最大;(3)雌鸟承担主要的育雏任务,喂食频率远大于雄鸟;(4)育雏期的不同阶段雏鸟乞食强度、亲鸟喂食频率变化很大:中期雏鸟乞食强度最大,亲鸟喂食频率最高,后期雏鸟乞食强度最弱;(5)整个育雏期雌性亲本没有表现出明显的偏爱行为,但雄性亲本在中、后期更偏爱体型大的雏鸟。可见杂色山雀子代的行为和体型大小影响着亲代的食物分配,亲代也会根据雏鸟日龄调整站位和喂食行为。     

Metabolic and endocrinologic complications in beta-thalassemia major: a multicenter study in Tehran

ABSTRACT : BACKGROUND : The combination of transfusion and chelation therapy has dramatically extended the life expectancy of thalassemic patients. The main objective of this study is to determine the prevalence of prominent thalassemia complications. METHODS : Two hundred twenty patients entered the study. Physicians collected demographic and anthropometric data and the history of therapies as well as menstrual histories. Patients have been examined to determine their pubertal status. Serum levels of 25(OH) D, calcium, phosphate, iPTH were measured. Thyroid function was assessed by T3, T4 and TSH. Zinc and copper in serum were determined by flame atomic absorption spectrophotometry. Bone mineral density (BMD) measurements at lumbar and femoral regions have been done using dual x-ray absorptiometry. The dietary calcium, zinc and copper intakes were estimated by food-frequency questionnaires. RESULTS : Short stature was seen in 39.3% of our patients. Hypogonadism was seen in 22.9% of boys and 12.2% of girls. Hypoparathyroidism and primary hypothyroidism was present in 7.6% and 7.7% of the patients. About 13 % of patients had more than one endocrine complication with mean serum ferritin of 1678 +/- 955 micrograms/lit. Prevalence of lumbar osteoporosis and osteopenia were 50.7% and 39.4%. Femoral osteoporosis and osteopenia were present in 10.8% and 36.9% of the patients. Lumbar BMD abnormalities were associated with duration of chelation therapy. Low serum zinc and copper was observed in 79.6% and 68% of the study population respectively. Serum zinc showed significant association with lumbar but not femoral BMD. In 37.2% of patients serum levels of 25(OH) D below 23 nmol/l were detected. CONCLUSION : High prevalence of complications among our thalassemics signifies the importance of more detailed studies along with therapeutic interventions.     

Patterns of serum carotenoid accumulation and skin colour variation in kestrel nestlings in relation to breeding conditions and different terms of carotenoid supplementation

Carotenoids are pigments synthesised by autotrophic organisms. For nestlings of raptorial species, which obtain carotenoids from the consumption of other heterotrophic species, the access to these pigments can be crucial. Carotenoids, indeed, have fundamental health maintenance functions, especially important in developing individuals as nestling kestrels. The aim of this study was to investigate how body carotenoid levels and skin pigmentation vary in kestrel nestlings (Falco tinnunculus) in relation to nesting parameters. Furthermore, we experimentally altered carotenoid availability (short- medium- and long-term) for nestlings and investigated skin and serum variance. The skin colour variance of 151 nestlings was explained by nest of origin, age and by the body condition (body mass corrected by age), older nestlings with higher body condition being redder. No difference in skin colour was detected between sexes. Differences in hue (skin “redness”) between treatments did not emerge during the first week, but did occur 15 days after administration between long-term supplemented and control chicks. In contrast, the serum carotenoid concentration showed a treatment-dependent increase after 5 days from the first carotenoid administration and at least after two supplemented feedings. In general, hue but not serum carotenoids, was correlated with the body condition of nestlings. Based on the increased skin pigmentation of nestling kestrels in the long-term experimental group, we suggest carotenoid availability to be limited for colour expression. The small increase of serum carotenoids due to supplementation is consistent with the hypothesis that there is a physiological constraint on these pigments, as well as an environmental limitation. The presented results are useful for the understanding of carotenoid uptake and accumulation by a wild raptorial species, located at the top of the food web, highlighting that carotenoids are a limited resource for kestrel nestlings.     

Changes in Serum Copper and Zinc Levels in Peripartum Healthy and Subclinically Hypocalcemic Dairy Cows

The objective of this study was to determine the levels of serum copper and zinc in subclinically hypocalcemic peripartum dairy cows in comparison to healthy animals. Blood samples were taken from 219 multiparous Holstein cows near parturition (from 4 weeks prepartum to 4 weeks postpartum) and 51 cows with subclinical hypocalcemia. The results showed that the serum copper concentration increased gradually at 1 week prepartum and remained high for the first 4 weeks postpartum in the healthy periparturient dairy cows. The serum zinc concentration reached a nadir at 1 week postpartum and subsequently increased gradually to baseline. The serum zinc concentration was significantly decreased (P?<?0.01) in dairy cows with subclinical hypocalcemia compared with healthy cows. There was no significant difference in the serum copper concentration between cows with subclinical hypocalcemia and healthy cows. These data demonstrate that the concentrations of copper and zinc in serum change dramatically during the peripartum period in dairy cows, which is a tremendous challenge for the body and for the maintenance of dairy cow health. The present study further suggests that a decreased serum zinc concentration could be a cause of decreased productive performance and increased susceptibility to other diseases due to immunosuppression in dairy cows with subclinical hypocalcemia. Additionally, this decreased zinc concentration may be involved in the pathogenesis of subclinical hypocalcemia.     

Physiological ecology of Mediterranean Blue Tits (Parus caeruleus). I. A test for inter-population differences in resting metabolic rate and thermal conductance as a response to hot climates

Blue Tits (Parus caeruleus) are widely distributed throughout Europe, reaching the southern limit of their range on islands in the Mediterranean and in northern Africa. On Corsica, one population located at Pirio in the Fango Valley breeds roughly one month later than populations in adjacent valleys or on the continent, thus exposing nestlings to high ambient temperatures (T(a)). We tested the hypothesis that nestlings and possibly adult Blue Tits at Pirio would exhibit a reduction in resting metabolic rate (MR) and an increase in thermal conductance as a physiological response to high T(a). We compared the thermoregulatory response and evaporative water loss for nestlings from Pirio in Corsica and one continental site (Vic-le-Fesq) and for adults from two Corsican (Pirio and Muro) and one continental site (La Rouvière). At 12-14 days of age, nestlings from Pirio showed two distinct thermoregulatory patterns. Nestlings under 8.0 g behaved as heterotherms, whereby MR was correlated only with body temperature. At body masses above 8.0 g nestlings progressively acquired the ability to regulate T(b) and at masses >9.0 g they behaved as homeotherms. When considering homeothermic nestlings and adults, population of origin did not affect either thermal conductance or resting MR. For homeothermic nestlings, mass-specific resting MR (mW x g-(1)) was 15.5 +/- 2.6 and 17.5 +/- 2.5 for nestlings from Vic-le-Fesq and Pirio, respectively. For adults, mass-specific resting MR (mW x g-(1)) was 17.5 +/- 2.0, 17.8 +/- 1.6, and 17.9 +/- 1.0 for birds from Pirio, Muro, and La Rouvière, respectively. Although there was a weak but positive effect of T(a) on evaporative water loss for homeothermic nestlings, no such trend was evident for adults over the range of T(a) tested in this study. We thus find no evidence to indicate that either nestlings or adults exhibit the exponential increase in evaporative water loss associated with the non-convective regulation of T(b) within the range of T(a) tested (roughly 相似文献   

Expression and purification of biologically active IGF-binding proteins using the LCR/Mel expression system

The anabolic effects and bioavailability of insulin-like growth factors I and II (IGF-I, IGF-II) are regulated in part by a family of IGF-binding proteins (IGFBPs). There are six known members of the IGFBP family, which share distinct structural characteristics and functional activities. To study the binding properties of these proteins, we have expressed recombinant IGFBP-3 and IGFBP-4 using the LCR/Mel expression system. Using this system, we found that recombinant IGFBP-3 was secreted by Mel cells and had a glycosylation pattern similar to that of native IGFBP-3. Recombinant IGFBP-4 secreted from Mel cells had a molecular size identical to that of non-glycosylated native IGFBP-4. The binding kinetics of recombinant IGFBPs was measured using a solid-phase ligand-binding assay, an in vitro solution-binding assay, and a cellular proliferation assay. IGF-I bound with high affinity to recombinant IGFBP-3 and IGFBP-4 with K(D)s of <0.25 nmol. As reported for native IGFBPs, IGF-II bound with affinity higher than IGF-I to recombinant IGFBP-3 and IGFBP-4 (K(D) of <0.05 nmol). Recombinant IGFBP-3 and IGFBP-4 were found to inhibit the IGF-induced proliferation of an NIH3T3 cell line engineered to overexpress the IGF-I receptor. We have compared the binding kinetics of Mel cell-expressed IGFBPs with that of recombinant protein expressed in Escherichia coli and found them to be equivalent. Here, we show that the LCR/Mel expression system represents an effective route for expression of biologically active IGFBPs.     

Nestling testosterone controls begging behaviour in the pied flycatcher, Ficedula hypoleuca

Begging signals and endogenous testosterone (T) levels of young birds have been shown to be positively correlated. If T is causally involved in controlling the level of begging effort, an endocrine control mechanism could explain the evolution of begging as a costly signal reflecting need. We tested experimentally whether elevated circulating T levels enhanced begging behaviour in nestling pied flycatchers, Ficedula hypoleuca. A pilot study confirmed that nestling T levels could be elevated within a natural physiological range using an oral dose of T. After T-dosing, nestling begging behaviour was measured as: i) the duration of begging displays and ii) the maximum height of begging stretches. Our results show that nestling T levels were elevated at 90 min post dosing and that at this time point both measures of begging behaviour were performed more intensely by T-dosed nestlings than controls. Nestling begging displays in response to dosing varied between individuals, which in part was explained either by the date in the breeding season or nestling mass. The results of this study confirm the causal nature of T in controlling nestling begging signals and suggest that it may be part of the mechanism that controls begging behaviour in nestling birds.     

Removal of copper by Pseudomonas putida strain S4 isolated from copper mines

A bacterial strain, Pseudomonas putida S4, was isolated from smelter drainage of copper mines. The strain exhibited resistance to several heavy metals, like aluminium (Al), zinc (Zn), nickel (Ni), cobalt (Co) besides copper (Cu). Strain S4 could accumulate Cu from the Cu-supplemented growth medium. In the present study, we have demonstrated the Cu2+ removal capacity of this strain from various samples such as mine effluent, low-grade ore and ore-tailings, collected from the mining site. Moreover, approximately 80% of the accumulated Cu2+ could be recovered from the loaded biomass by a simple desorption procedure.     

Spasticity Treatment Ameliorates the Efficacy of Melatonin Therapy in Experimental Autoimmune Encephalomyelitis (EAE) Mouse Model of Multiple Sclerosis

Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease in the central nervous system (CNS). Melatonin is an effective treatment in MS patients and experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Melatonin secretion peaks at 2 AM, concomitant with the time at which the muscles are resting and the body is exerting its antioxidant activity. The current study was designed to investigate combination treatment of baclofen, a muscle relaxant drug, and melatonin in EAE mice. Results showed that melatonin (Mel) alone or in combination with baclofen (Bac + Mel) reduced clinical scores and demyelination by significantly increasing myelin oligodendrocyte glycoprotein (MOG) levels, a marker for mature oligodendrocytes, compared to EAE mice. Moreover, Mel or Bac + Mel therapy caused a significant increase in IL-4 serum levels, an anti-inflammatory cytokine, whereas IFN-γ serum levels, a pro-inflammatory cytokine, were significantly reduced. On the other hand, Mel or Bac + Mel caused a significant reduction in malondialdehyde (MDA) levels, a marker of oxidative stress, in comparison to EAE mice. In contrast, the activity of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) was significantly increased in Mel and Bac + Mel groups. In summary, combination therapy improved clinical scores and tend to enhance the efficiency of melatonin treatment by further promoting remyelination, decreasing inflammation, and stimulating the activity of antioxidant enzymes, which suggests that prior spasticity treatment increases the efficacy of melatonin therapy in EAE mouse model of MS. Further experimental and clinical studies are needed to ensure the beneficial role of this combination strategy.