Origina6a Role of Lipid Peroxidation and Vitamin E in Magnesium Deficiency 1 1 1 2 2 \ T. Giinther ), J. Vonnann ), V. Hollriegl ), G. Disch ), H.-G. Classen ) Zusammenfassung Summary Resume Es wurde untersucht, ob Lipidperoxidation an The aim of the study was to ascertain whether Le but de la presente etude etait de verifier den Erscheinungen des Mg-Mangels beteiligt lipid peroxidation is involved in the effects of l'eventuelle implication de la peroxydation ist. Dazu wurde 115 g schweren mannlichen Mg deficiency. Male Wistar rats, weighing 115 des lipides dans les effets des deficits en ma­ Wistarratten eine Kontroll-, eine Mg-arme, g, were fed a control, an Mg-deficient, an Mg­ gnesium. Des rats Wistar males pesant 115 g eine Mg-arme plus Vitamin E-arme und eine deficient plus vitamin E-reduced and an Mg­ ont re<;u pendant 11 semaines les differents Mg-arme Vitamin E-reiche Diat 11 Wochen deficient-vitamin E-supplemented diet for 11 regimes alimentaires suivants: regime temoin, lang verftittert. Anschlief:lend wurden Vita­ weeks. At the end of the experiment, vitamin regime carence en Mg, regime carence en Mg min E, Malondialdehyd und der Mineralge­ E. malondialdehyde and mineral content were et pauvre en vitamine E et, enfin, regime halt in Serum, Leber, Herz, Nieren, Aorta, measured in serum, liver, heart, kidney, aorta, carence en Mg et supplemente en vitamine E. Hoden und Skelettmuskel gemessen. testis and skeletal muscle. Mg deficiency re­ A la fin de !'experimentation, les auteurs ont Mg Mange[ verminderte den Vitamin E-Ge­ duced vitamin E in serum and all examined mesure les taux seriques, hepatiques, cardia­ halt im Serum und alien untersuchten Gewe­ tissues. Vitamin E supplementation of Mg­ ques, renaux, aortiq ues, testiculaires et muscu­ ben. Vitamin E-Supplementation erhi:ihte den deficient rats produced only a slight increase losquelettiques de vitamine E, d'aldehyde a-Tocopherolgehalt besonders in der Leber. in a-tocopherol levels, except for the liver, malonique et de substances minerales. Mg-Mangel erh6hte den Malondialdehyd­ which stored a considerable amount. Le deficit magnesique a reduit les concentra­ Gehalt, besonders bei Vitamin E-reduzierter Mg deficiency increased malondialdehyde, tions de vitamine E dans le serum et dans to us Diat. Die durch Mg-Mangel hervorgerufenen particularly in rats also fed the low vitamin E les tissus examines. Une supplementation en Veranderungen im Mineralgehalt der Gewe­ diet. Mgdeficiency-induced alterations in min­ vitamine E chez les animaux carences en Mg a be, die Erytheme, die malign en T-Zellympho­ eral content of the tissues, erythema, develop­ entralne une augmentation des taux d'a-toco­ me, Leukamien und Tumore wurden durch ment of malignant T cell lymphoma, leukemia pherol, en particulier dans le foie. Les altera­ Vitamin E-S upp lementation nicht verhindert. and development of tumors were not pre­ tions de la teneur tissulaire en substances Nurdie durch Mg-Mangel entstandenen Hau­ vented by vitamin E supplementation. Only minerales, les erythemes, les lymphomes des tulzerationen wurden durch Vitamin E signifi­ skin ulcerations in Mg deficien~)' were signifi­ cellules T, les leucemies et les effets tumorige­ kant vermindert. cantly reduced by vitamin E. nes induits par la carence magnesique n'ont pas ete minimises par la supplementation en vitamine E, n'a reduit significativement Introduction content, cardiac necroses and in­ lead to the increased ea-dependent creased collagen content in heart and release of some hormones, such as Significant effects of experimental neuromuscular hyperexcitability [1, 2, catecholamines, prostaglandins and Mg deficiency in rats are transient 3, 4, 5]. related substances [6]. erythema and edema, skin lesions, The basic pathobiochemical mechan­ Moreover,inMg deficiency, increased reduced growth, development of ma­ ism ofMg deficiency may be an altera­ lipid peroxidation (LPO) was found lignant T-celllymphoma and leuke­ tion of the Mg-Ca-antagonism in the in isolated liver mitochondria [7] and mia, development of intestinal tumors, extracellular fluid and at membranes in liver in vivo [8]. Mg deficiency­ calcification ofkidneys and large blood 2 due to reduced extracellular Mg ' con­ induced cardiac necrosis was effec­ vessels, changed intracellular mineral centration [6]. This effect is an explan­ tively reduced in a dose-dependent ation for the Mg deficiency-increased manner by simultaneous adminis­ cell membrane permeability and ion tration of vitamin E to Mg deficient 1 ) Institute of Molecular Biology and Bio­ turnover and the increased effect of Syrian hamsters [9 ]. Since vitamin E is chemistry, Free University of Berlin, FRG 2 hormones on smooth muscle cells act­ ) Department of Pharmacology and Toxi­ one of the most effective scavengers 2 2 cology of Nutrition, ing via Ca + influx and rise in [Ca +]i. of free radicals [10], these results sug­ University of Hohenheim, Stuttgart, FRG The altered Mg-Ca ratios may also gest that free radical mechanisms are Magnesium-Bulletin 14, 2 (1992) 57 Lipid Peroxidation in Magnesium Deficiency involved in Mg deficiency-induced per cage Type Ill) were kept at a VitaminE was determined by its fluor­ myocardial injury. light-dark cycle from 8 a.m. to 8 p.m. escence in hexane extracts according The same relationship may hold for at a temperature of 21 ± 1 oc and a to Taylor et al [20]. human ischemic heart disease (IHD). relative humidity of 50--60 % for 11 Malondialdehyde (MDA) was deter­ Epidemiological studies revealed a weeks. Body weight was measured mined by a variation of the thiobar­ strong inverse correlation between weekly. bituric acid (TBA) method [21, 22]. A IHD mortality and the serum level of At the end of the experiment the rats 20% homogenate in 150 mmol/1 KCl vitamin E, whereas the classic risk were anesthesized with nembutal (or serum) was diluted 1:1 (v/v) with factors cholesterol and diastolic blood (50 mglkg i.p.) and blood, liver, kid­ 5 % trichloroacetic acid (TCA) and pressure had only a moderate asso­ neys, heart, testes and aorta were centrifuged for 5 min at 13 000 x g. ciation with IHD [11]. Alteration of taken, frozen in liquid nitrogen and 500 j..tl TBA (1%, pH7) was added to ion permeability and LPO, adversely stored at 20 oc. 500 j..tl supernatant and heated at 95 oc affected by Mg deficiency, may act Intestines were inspected for intes­ for 15 min. After cooling, the probes in accord. An increase in intra­ tinal tumors [17]. Thymus was in­ were extracted with 3 ml1-butanol by cellular Ca2~ can enhance LPO [12]. spected formalignent T celllymphoma vortexingfor 30 sec and centrifugation Mg deficiency-increased release of [18], removed and weighed. Leuco­ at 2100 g for 15 min. MDA in the catecholaminesmayincrease LPO [13] cyte content was countedinlymphoma butanol phase was measured fluor­ and Mg deficiency-induced alteration bearing rats by means of a Neubauer ometrically (Perkin Elmer LS 50, ex­ of fatty acids in phospholipids may chamber. citation: 532 nm, emission: 553 nm, slit increase LPO. Increased LPO may Blood was centrifuged at 1000 g for width: 5 nm). lead to an increase in membrane per­ 5 min. The concentrations of Mg, Ca, The calibration curve was prepared meability [14] and may enhance the and Fe in serum were measured by with malonaldehyde tetraethylacetal effects of Mg deficiency. Since LPO atomic absorption spectrophotometry (Sigrna ), which was treated in the same may be a general pathological mechan­ (AAS). way. Statistical analysis was performed ism [14], LPO may play a significant Portions of the livers and hearts were as indicated in the tables. role in the pathology ofMg deficiency. freeze-dried. Dried liver was powd­ To clarify the realtionship between ered in a plastic mortar, freeze-dried Mg deficiency and LPO, we fed a low hearts were powdered by means of a Results and Discussion vitamin E diet, and a vitamin E sup­ vibrating steel ball (Mikro-Dismem­ plemented diet to rats on a Mg de­ brator, B. Braun, Melsungen, FRG). ficient diet. For determination of Na, K, Mg, Ca, Vitamin E content (tab. 2) and Fe in livers and hearts, freeze­ In serum and all investigated tissues, dried, powdered tissue was ashed in vitamin E content was reduced by MateriaJs and Methods the Plasma Processor 200-E (Tech­ Mg deficiency. This reduction was es­ nics, Miinchen, FRG). The ash was pecially pronounced in serum and After obtaining approval of local dissolved in 0.1 N HCl. N a and K liver. When Mg deficiency was com­ authorities and the Animal Protection were measured by flame photometry bined with vitamin E reduction, the Committee, the experiment with 175 (Klina, Beckman), Mg, Ca and Fe vitamin E content was drastically re­ male Wistarrats, weighing115 g(Inter­ were measured by AAS (Philips, duced, particularly in liver. After feed­ fauna, Tuttlingen, FRG) was under­ SP9). ing the vitamin E-supplemented diet taken. Males were used, because of An aliquot of freeze-dried, powdered to Mg-deficient rats, vitamin E con­ their greater susceptibility to free-radi­ hearts was taken for determination of tent in serum and tissues was some­ cal-induced hepatotoxicity [15]. A collagen content by means ofmeasure­ what higher than in controls. How­ control diet (described elsewhere [16]) ment of hydroxyproline according to ever, in liver, vitamin E was markedly was fed to 25 rats (group A); Mg­ Stegemann [19]. increased. deficient diet was fed to 150 rats, de­ These results indicate that liver cells vided into 3 groups: group B (Mg store vitamin E, and this store can deficiency alone), group C (also vita­ Tab.l: ContentofMg. Ca,FeandvitaminEin be more depleted in vitamin E de­ control (A), Mg-deficient (B), Mg-deficient min E reduced), and group D (fed plus vit E-reduced (C) and Mg-deficient-vit E­ ficiency as compared with other excess vitamin E supplements).