Ultrastructure of the Optic Nerve in Magnesium-Deficient Rats

Gong, Huaqing; Takami, Yumiko; Amemiya, Tsugio

doi:10.1159/000069132

Cited by 13 publications

(12 citation statements)

References 23 publications

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“…Gong and Amemiya 44 showed ultrastructural disarrangement in the retina of manganese-deficient rats. A reduction of the percentage of myelinated axons and the myelin area was found in the ON of undernourished rats.…”

Section: Discussionmentioning

confidence: 98%

“…11,12 Trace elements deficiency, undernourishment, and exposure to drugs of abuse or alcohol induced ultrastructural changes in the ON, cornea, and retina. 25,26,29,[31][32][33][34][35][42][43][44][45][46][47][48][49][50][51][52][53] Figure 2 Mean density (a) and total number (b) of myelinated and unmyelinated fibres of the optic nerve in the control, anaemic, and recovered rats at postnatal day 32. Values are means ± SE for n ¼ 6; *Po0.05.…”

Section: Discussionmentioning

confidence: 99%

“…60 Insults, such as trace elements deficiency, malnutrition, or even altered functioning of the thyroid gland, can influence the myelination process in a persistent manner. 25,[44][45][46]53,61 Myelinogenesis continues until adolescence in both rodents 61 and humans. 62,63 It is known that myelinogenesis in the rat ON starts around PND 7, and between the second and fifth weeks of the postnatal period that a rapid increase in myelination is observed.…”

Section: Discussionmentioning

confidence: 99%

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Effectiveness of iron repletion in the diet for the optic nerve development of anaemic rats

Demaman

Melo

Homem

et al. 2009

Eye

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Purpose To compare the process of myelination in the developing optic nerve (ON) of anaemic rats with the subsequent recovery after being fed an iron-recovery diet. Methods In this study, the morphometrical parameters in the ON were assessed by electron microscopy in Wistar rats that were on an iron-deficient diet for 32 days or for 21 days followed by 10 days on an iron-recovery diet. Qualitative and quantitative analyses were performed using representative electron ultramicrographs. Data were analysed by one-way analysis of variance (ANOVA). When differences were detected, comparisons were made using Tukey's post hoc test (Po0.05 was considered to be significant). Results Qualitative analysis of the ONs in anaemic and recovered animals showed a higher rate of deformed axons and increased lamellar separation in the myelin sheath when compared with the respective control group. The ON of the anaemic group showed a reduced mean density of myelinated fibres when compared with the control group. The fibre area ratio, axon area ratio, and myelin area ratio of large axons/small axons in the ONs of the control group showed the highest values for the myelin areas, axon areas, and total fibre areas. The control group showed a significantly higher myelin sheath thickness when compared with the anaemic and recovered groups. Conclusions Our data indicate that iron is necessary for maintenance of the ON cell structure, and that morphological damage from iron deficiency is not easily reverted by iron repletion.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Effectiveness of iron repletion in the diet for the optic nerve development of anaemic rats

Demaman

Melo

Homem

et al. 2009

Eye

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“…Caddell proposed a hypothesis that magnesium deficiency may be one of causative factors for the pathogenesis of retinopathy of prematurity as well as high arterial oxygen pressure, because magnesium deficiency results in impairment of both vasodilatator activity and protection from oxidative injury [35]. Magnesium deprivation during developmental phase may cause myelination disorders and multifocal necrosis in optic nerve [36]. Magnesium also may be necessary for maintenance of corneal surface health which is important for protection from infections and dryness.…”

Section: Necessity In Terms Of Eye Tissue Developmentmentioning

confidence: 99%

Magnesium: Effect on ocular health as a calcium channel antagonist

Korkmaz

Ekici²,

Tufan³

et al. 2013

J Clin Exp Invest

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ÖZETMagnezyum hücre zar fonksiyonlarını, düz kas kontraksiyonlarını ve enzimatik reaksiyonları etkileyerek pek çok metabolik sürece katılan fizyolojik bir kalsiyum kanal blokörüdür. Magnezyumun Endothelin-1 (ET-1) ve Nitrik Oksit (NO) yolakları vasıtasıyla endotel fonksiyonları-nı modifiye ederek dokulara kan akımında artışa neden olduğu gösterilmiştir. Magnezyum aynı zamanda N-metil-D-aspartat (NMDA) reseptör ilişkili kalsiyum içe akımı-nı bloke ederek ve glutamat serbestleşmesini önleyerek nöroprotektif rol oynamakta ve hücreleri oksidatif stres ve apoptoza karşı korumaktadır. Hem kan akımında artışa neden olması hem de nöroprotektif etkileri magnezyumu glokom çalışmaları için iyi bir hedef molekül yapmaktadır. Magnezyumun retinada oksidatif stresi ve apoptozu azalttığı ve ganglion koruyucu etkileri olduğu gösterilmiştir. Bir takım çalışmalarda aynı zamanda magnezyumun diabetik hastalarda insulin resistansını azalttığı, glisemik kontrolü kolaylaştırdığı ve retinopatiyi önlediği gösterilmiştir. Magnezyumun lensteki iyon dengesinin sağlanmasında kritik önemi belirlenmiştir. Magnezyum eksikliğinin lentiküler oksidatif stresi arttırdığı ve iyon dengesini bozarak katarakt oluşumuna neden olduğu gösterilmiştir.Anahtar kelimeler: Magnezyum, kalsiyum kanal blokajı, glokom, nöroproteksiyon, diabetik retinopati, katarakt ABSTRACTMagnesium is the physiologic calcium channel blocker, involving in many different metabolic processes by maintaining cell membrane function, modulating smooth muscle contraction and influencing enzymatic activities. Magnesium has been shown to increase blood flow to tissues by modifying endothelial function via endothelin-1 (ET-1) and nitric Oxide (NO) pathways. Magnesium also exhibits neuroprotective role by blocking N-methyl-D-aspartate (NMDA) receptor related calcium influx and by inhibiting the release of glutamate, hence protects the cell against oxidative stress and apoptosis. Both increase in blood flow and its neuroprotective effect make magnesium a good candidate for glaucoma studies. Magnesium has been shown to decrease oxidative stress and apoptosis in retinal tissue and to have retinal ganglion cell sparing effect. A series of studies has been conducted about magnesium could decrease insulin resistance in diabetic patients, ease glycemia control and prevent diabetic retinopathy. Magnesium is found to be critically important in maintaining normal ionic homeostasis of lens. Magnesium deficiency has been shown to cause increased lenticular oxidative stress and ionic imbalance in the lens so trigger cataractogenesis. J Clin Exp Invest 2013; 4 (2): 244-251

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“…It is therefore of great importance to detect magnesium deficiency in the organism (Feillet-Coudray et al 2003;Gong et al 2003;Hoane et al 2003;Lajer et al 2003;Rude et al 2003). Some authors recommend the use of magnesium concentrations in serum for assessment of deficiency, but others argue that the loading test will provide more exact results, because in the presence of normal serum values intracellular magnesium may be deficient (Stalnikowitz 2003).…”

mentioning

confidence: 99%

Serum and Tissue Concentrations of Magnesium, Calcium, Potassium and Sodium in Rats

Wilhelm¹,

Pechová²,

Scheer³

et al. 2005

Acta Vet. Brno

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Wilhelm Z., A. Pechová, P. Scheer, J. Kleinová, L. Roubalíková: Serum and Tissue Concentrations of Magnesium, Calcium, Potassium and Sodium in Rats. Acta Vet Brno 2005, 74: 183-190.The aim of the study was to analyze concentrations of magnesium in the serum and selected tissues of Wistar rats (erythrocyte, myocardium, rectus abdominis muscle, femoral bone, lung, spleen, small intestine, liver, kidney and uterus in females) and to evaluate the relationships between serum and tissue concentrations of magnesium, calcium, potassium and sodium.Adult laboratory rats (Wistar strain, n = 39) were studied. The animals were allocated to three groups as follows: females (F; n = 18; body mass, 269 ± 33 g), males I (M I; n = 10; 413 ± 30 g) and males II (M II; n = 11; 633 ± 78 g). The females and males were of the same age (10 -12 weeks), the males II were older (22 -24 weeks). Blood was drawn by cardiac puncture under ether anesthesia. After sacrificing the animals under ether anesthesia, tissue samples were collected from the tissues to be studied and analysed for the presence of magnesium, calcium, potassium and sodium. Flame atomic absorption spectrophotometry was used to assess the concentration of magnesium in sera and, after sample mineralization, in all the tissues investigated. In conclusion, significant differences in myocardial magnesium concentrations among the groups and non-significant differences in sera and erythrocytes suggest that the actual concentration of intracellular magnesium, i.e. in myocardium and other tissues, cannot be derived from either serum or erythrocyte concentrations. Interestingly, in female rats there was a negative correlation between magnesium and calcium levels in the myocardium, while in both male rat groups (males I and males II) this correlation was positive.

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Ultrastructure of the Optic Nerve in Magnesium-Deficient Rats

Cited by 13 publications

References 23 publications

Effectiveness of iron repletion in the diet for the optic nerve development of anaemic rats

Effectiveness of iron repletion in the diet for the optic nerve development of anaemic rats

Magnesium: Effect on ocular health as a calcium channel antagonist

Serum and Tissue Concentrations of Magnesium, Calcium, Potassium and Sodium in Rats

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