| Abstract | Ciljevi istraživanja: Istražiti promjene u ekspresiji glukoznih transportera
GLUT1, GLUT2 i GLUT4 u mozgu zdravih, dijabetičkih i liječenih dijabetičkih
štakora polifenolima lišća masline.
Materijal i metode: U radu su korištene lijeve polutke mozga mužjaka Wistar
štakora podijeljenih u četiri skupine: C (Kontrola) – kontrolna skupina bez
tretmana; DMT1 – skupina s razvijenim dijabetesom nakon osam dana od
jednokratnog iniciranja streptozotocina (i.p., 60 mg/kg); DMT1+OLE –
skupina s razvijenim dijabetesom i posttretirana i.p. iniciranjem ekstrakta
polifenola lišća masline (OLE); DMT2 – skupina je hranjena visoko masnom
hranom tijekom 30 dana (standardna laboratorijska hrana obogaćena je
50 % palminim uljem). Skupine su sadržavale 3-5 životinja, starosti 2-3
mjeseca. Homogenati mozga korišteni su u WB analizi. Za procjenu
podataka korišten je program Statistica (softverski sustav za analizu
podataka), verzija 14 (TIBCO Software Inc., 2020., Palo Alto, CA, SAD).
Razlike između skupina procijenjene su jednosmjernom analizom varijance
(ANOVA One-way) praćenom post hoc Schefféovim testom. Regresijska
analiza (linearna regresijska analiza) korištena je za usporedbu međusobne
ovisnosti varijabli. Statistička značajnost određena je p vrijednosti manjom
od 0,05 (p<0.05) za faktor korelacije R.
Rezultati: U provedenim eksperimentalnim uvjetima, DMT1 i DMT2
pospješili su ekspresiju GLUT1, neznatno suprimirali GLUT2 i blago
eksprimirali GLUT4. Liječenje dijabetičnih životinja ekstraktom polifenola
lišća masline povećalo je ekspresiju GLUT1, nije utjecalo na ekspresiju
GLUT2 i GLUT4. U odnosu na DMT1, uočena je ekspresija GLUT1 u skupini
DMT2.
GLUT1 i GLUT2 statistički su se značajno mijenjali ovisno o istraživanim
skupinama (p=0,0055, odnosno p=0,0079). Statistički značajna razlika u
ekspresiji GLUT1 pronađena je između Kontrole i DMT1+OLE skupine
(p=0,0138) te između Kontrole i DMT2 skupine (p=0,0127). U odnosu na
Kontrolu, statistički značajna razlika u ekspresiji GLUT2 pronađena je u
DMT1 skupini (p=0,0174) i DMT2 skupini (p=0,0182). GLUT1 negativno je
korelirao s GLUT2 (r=-0,67) i β-aktinom (r=-0,68), GLUT2 sa GLUT4 (r=-
0,71), a pozitivno s β-aktinom (r=0,81). GLUT4 negativno je korelirao s βaktinom (r=-0,70). β-aktin statistički se značajno mijenjao ovisno o
skupinama (p=0,0000). U odnosu na Kontrolu, β-aktin je bio značajno
suprimiran u DMT1 skupini (p=0,0001), DMT1+OLE skupini (p=0,0002) i
DMT2 skupini (p=0,0000).
Zaključak: Na osnovu provedenog istraživanja utvrđena je važnost
određivanja glukoznih transportera mozga u dijabetesu i unosu
farmakoloških pripravaka. Visoke razine glukoze u DMT1 povećale su
ekspresiju GLUT1 koju terapija ekstraktom lišća masline, u tako kratkom
vremenu (sedam tretmana) nije smanjila.
Iako su naši rezultati suprotni onima u literaturi, smatramo da je za bolje
poznavanje regulacije glukoze putem glukoznih transportera potrebno
dodatno istraživanje koje omogućuju druge tehnike lokalizacije GLUT u
mozgu. |
| Abstract (english) | Research Objectives: To study the changes in the expression of glucose
transporters GLUT1, GLUT2 and GLUT4 in the brain of healthy, diabetic and
diabetic rats treated with olive leaf polyphenols.
Material and Methods: The left cerebral hemispheres of male Wistar rats
were used for the work, which were divided into 4 groups: C (control) -
control group without treatment; DMT1 group with developed diabetes after
8 days of single administration of streptozotocin (i.p., 60 mg/kg); DMT1+
OLE - group with developed diabetes and post-treatment i.p. by
administration of olive leaf polyphenol extract (OLE); DMT2 group was fed
a high-fat diet for 30 days (standard laboratory diet enriched with 50%
palm oil). Groups consisted of 3-5 animals aged 2-3 months. Brain
homogenates were used for analysis of WB. Statistica (data analysis
software), version 14 (TIBCO Software Inc., 2020, Palo Alto, CA, USA) was
used for data analysis. Differences between groups were assessed using a
one-way analysis of variance (ANOVA one-way) followed by a post hoc
Scheffé test. Regression analysis (linear regression analysis) was used to
compare the interdependence of variables. Statistical significance was
determined with a p value of less than 0.05 (p < 0.05) for the correlation
factor R.
Results: Under the experimental conditions performed, DMT1 and DMT2
enhanced the expression of GLUT1, slightly suppressed GLUT2 and
expressed GLUT4 to a small extent. Treatment of diabetic animals with olive
leaf polyphenol extract increased the expression of GLUT1 but had no effect
on the expression of GLUT2 and GLUT4. Compared with DMT1, GLUT1
expression was observed in the DMT2 group.
GLUT1 and GLUT2 changed statistically significantly depending on the
groups studied (p=0.0055 and p=0.0079, respectively). A statistically
significant difference in GLUT1 expression was observed between the
control and DMT1+ OLE groups (p=0.0138) and between the control and
DMT2 groups (p=0.0127). Compared to control, a statistically significant
difference was found in GLUT2 expression in DMT1 group (p=0.0174) and
DMT2 group (p=0.0182). GLUT1 correlated negatively with GLUT2 (r=-
0.67) and β-actin (r=-0.68), GLUT2 with GLUT4 (r=-0.71), and positively
with β-actin (r=0.81). GLUT4 was negatively correlated with β-actin (r=-
0.70). β-Actin changed statistically significantly as a function of groups
(p=0.0000). Compared to control, β-actin was significantly suppressed in
DMT1 group (p=0.0001), DMT1+ OLE group (p=0.0002) and DMT2 group
(p=0.0000).
Conclusion: Based on the conducted research, the importance of
determining glucose transporters in the brain in diabetes and taking
pharmacological preparations was established. High glucose levels in DMT1
increased GLUT1 expression, which was not decreased by olive leaf extract
therapy in such a short time (7 treatments).
Although our results are in contrast to those in the literature, we believe
that further research should be conducted to better understand glucose
regulation by glucose transporters, allowing other GLUT localization
methods in the brain. |
