Introduction.Thedevelopmentofapproachesforeffectivecontrolofdiabetes-induced deterioration of lipidmetabolis- mand plasma glucose level could be implemented by the applying of germanium-contained biologically active substances. Amongotherssuchcompoundasniacin – oxyethylidendiphosphonatogermanate (MIGU-4) with molar mass of 593 G/mol shouldbementioned, whichisabletocorrecteffectivelythe lipidlayersoflivermitochondrialmembranes on models of streptozotocin – induceddiabetes.
Aim.Toinvestigatethedynamicchangesofthetotalcholesterol, total phospholipids levelalongwiththeir molarratio;fractionsofphospholipidsofbotherythrocytemembranesandlivermitochondriamembranesinexperimentaldiabetes 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.
MaterialsandMethods. DiabeteswasinducedinmaleWistarratswithstreptozotocininjection(50.0 mg/kg., i. p.). ED50ofMIGU-4 (25.0 mg/kg, i. p.) wasused. Cellularmembraneswereobtainedfromerythrocytes, andmitochondrialmembraneswereobtained through differential centrifugation of liver tissue. Lipidextracts were isolatedfrom1 goferythrocytemassandfrom 200 mgoflivertissue;phospholipidsfractionationwas carried out by methodofascending one-dimensional thin-layerchromatography. 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-АNS), which bears electronegativityand is diving only at the depth of superficial layer of lipids; hydrophobicone – N -phenyl-1-naphtalamine (1-PNА), which contains sulphategroups and is able to dive deeply into lipid bilayer (up to 8 Аоfromthreemethylaminogroupsofphospholipids). The next indices have been measured : fluorescenceintensity (Fmol), specificnumberofzondsbinding (N), constant of binding (Кb) aswellasdissociationconstant (Kd) ofzonds. Membranes were got via liver homogenates centrifugation, with the ourity checking via light mictroscopy. Thefluorescencewasverifiedwithspectrophotometer “Opton” (Germany) at the next wave lengths: 360 and 480 nm for ANS; 350 and 420 nm for 1-PNA.
Results. Thelevelofglucoseinbloodwas 15,14+0,83; 14,02+ 0,76, аnd 10,25+ 0,39 mmol/Lintwoweeks, one, andthreemonthsfromthemomentofMIGU-4 administrationcorrespondently. 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 administrationinducedpronouncedcorrectionoflisteddeteriorations,whilethoseonescontinuekeptdifferenceswhencom paredwithcontroldata. ThecombinedusageofMIGU-4 and insulininvestigatedindiceswerenotdifferent from controlones.
Conclusions.1.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.
2.TheexperimentalSTZ-induceddiabetesischaracterizedbysubstantialdeteriorationofmorpho-functional state of lipidmitochondriamembrane, which are more pronounced oin the superficial layer of lipids.Theusageofniacin – oxietilyden-diphosphonate-germanate (NicH)2[Ge(OH)2 (Oedph)].H20 (MIGU-4) amelioratedthediabetes- inducedchangesoflipidbilayerand increased the therapeutic effect of insuline.