Introduction. The development of approaches for effective control of diabetes-induced deterioration of lipid metabolism and plasma glucose level could be implemented by the applying of germanium-contained biologically active substances. Among others such compound as niacin - oxyethylidendiphosphonatogermanate (MIGU-4) with molar mass of 593 G/mol shouldbementioned, which is able to correct effectively the lipid layers of liver mitochondrial membranes on models of streptozotocin - induceddiabetes.
Aim. To investigate the dynamic changes of the total cholesterol, total phospholipids level along with the irmolarratio; fractions of phospholipids of both erythrocyte membranes and liver mitochondria membranes in experimental diabetes mellitus and to investigate the mentioned indices under conditions of complex correction by MIGU-4 and insulin. Besides, the investigations of the hepatocytes membrane state under conditions of experimental diabetes and it’s treatment with MIGU-4 were performed.
Materials and Methods. Diabetes was induced in male Wistarrats with streptozotocin injection (50.0 mg/kg., i. p.). ED50 of MIGU-4 (25.0 mg/kg, i. p.) was used. Cellular membranes were obtained frome rythrocytes, and mitochondrial membranes were obtained through differential centrifugation of liver tissue. Lipidextracts were isolated from1 goferythrocytemass and from 200 mg of liver tissue; phospholipids fractionation was carried out by method of ascending one-dimensional thin-layer chromatography. Content of certain phospholipids was estimated by method of spots “burning out” using the 72 % chloride acid at 200 0С up to their complete bleaching with the consequent determination of lipids phosphate. The level of total phospholipids was calculated by summing up all fractions content. For membrane state investigations fluorescence zonds have been explored: universal one - 1- anilinenaphtaline -8- sulphonate (1,8-ANS), which bears electronegativityand is diving only at the depth of superficial layer of lipids; hydrophobicone - N -phenyl-1-naphtalamine (1-PNA), which contains sulphate groups and is able to dive deeply into lipid bilayer (up to 8 Ао from three methylamino groups of phospholipids). The next indices have been measured : fluorescenceintensity (Fmol), specificnumber of zonds binding (N), constant of binding (Kb) as well as dissociation constant (Kd) of zonds. Membranes were got via liver homogenates centrifugation, with the ourity checking via light mictroscopy. The fluorescence was verified with spectrophotometer “Opton” (Germany) at the next wave lengths: 360 and 480 nm for ANS; 350 and 420 nm for 1-PNA.
Results. The level of glucose in blood was 15,14+0,83; 14,02+ 0,76, and 10,25+ 0,39 mmol/Lintwoweeks, one, and three months from them oment of MIGU-4 administration correspondently. The level of glucose in insulin - treated rats at analogous time of observation was 10,37+ 0,95; 8,17+ 0,64 and 7,89+0,39 mmol/Lcorrespondently. The total cholesterol level substantially elevated along with the decreasing of phospholipids content in both erythrocyte and mitochondrial membranes obtained from liver tissue in two weeks after experimental streptozotocin diabetes induction in rats. It resulted in an increase of the cholesterol/ phospholipids ratio. These changes reached the maximal expression of mentioned deteriorations during the second month from the moment of diabetes induction. This was paralleled by a shift of phospholipids fractions which manifested in the increase of fractions which were relatively resistant to oxidation (lysophosphatidylcholine, sphingomyelin) along with the drastic dropping down of fractions which were easily oxidized (phosphatidylcholine, phosphatidylethanolamine), and that indicated violation of membrane fluidity maintaining compensatory mechanisms. Separate administration of insulin and MIGU-4 slightly decreased the negative influence of diabetes-induced deteriorations on both total phospholipids and their fractions content. Combined administration of insulin and MIGU-4 was resulted in significant prevention of the diabetes-induced disturbances of total and fractional phospholipids as well as disturbances of cholesterol/ phospholipids coefficient. In STZ-diabetesFmolof 1,8-ANS zondwas reduced in more eight times when compared with the control. At the same time Kband N increased by five times while the constant of dissociation (Kd) decreased by more than four times. In STZ diabetes the Fmolof 1-PNA zond was reduced by 61,2%, whileN raised more than two times pertained to the control data.MIGU-4 administration induced pronounced correction of listed deteriorations, while those ones continue kept differences when compared with control data. The combined usage of MIGU-4 and insulin investigated in dices were not different from controlones.
- .The application of MIGU-4 prevents the streptozotocin diabetes-induced lipid metabolism disturbances in a form of total phospholipids and their fractions content violation in cellular and mitochondrial membranes.
- . The experimental STZ-induced diabetes is characterized by substantial deterioration of morpho-functional state of lipid mitochondria membrane, which are more pronounced oin the superficial layer of lipids. The usage of niacin - oxietilyden-diphosphonate-germanate (NicH)2 [Ge(OH)2 (Oedph)].H20 (MIGU-4) ameliorated the diabetes- induced changes of lipidbilayer and increased the therapeutic effect of insuline.