| Abstract | Cilj istraživanja: Istražiti mijenja li se izražaj CaMKII u neuronima spinalnih ganglija dijabetičkih štakora dva mjeseca nakon indukcije dijabetesa.
Ustroj istraživanja: Prospektivno istraživanje s laboratorijskim životinjama.
Mjesto istraživanja: Laboratorij za istraživanje boli Medicinskog fakulteta u Splitu.
Eksperimentalne životinje: U istraživanju su korištena 33 štakora: 14 u skupini modela dijabetesa tipa 1 (DM1), 7 u kontrolnoj skupini za model dijabetesa tipa 1 (CON-DM1), 7 u skupini modela dijabetesa tipa 2 (DM2) i 5 u kontrolnoj skupini za model dijabetesa tipa 2 (CON-DM2). Model DM1 izazvan je intraperitonealnom injekcijom 55 mg/kg streptozotocina, dok je model DM2 izazvan kombinacijom niske doze streptozotocina (35 mg/kg) i hrane s visokim udjelom masti. Kontrolne životinje dobile su intraperitonealnu injekciju citratnog pufera. DM1 i CON-DM1 životinje hranjene su standardnom laboratorijskom hranom za štakore, dok je CON-DM2 skupina hranjena hranom s visokim udjelom masti.
Glavne mjere ishoda: Glikemija, tjelesna masa i izražaj enzima CaMKII i njegovih izoformi (α, γ, δ) u neuronima spinalnih ganglija štakora.
Rezultati: Izražaj ukupne CaMKII (tCaMKII) u neuronima spinalnih ganglija 2 mjeseca nakon injekcije streptozotocina bio je značajno veći u DM1 štakora (16±0.9) u usporedbi s CON-DM1 štakorima (14±2.0) (neparni t-test, P<0.05). Značajna razlika u izražaju tCaMKII postoji na razini svih analiziranih neurona, ali ne i u analiziranim podskupinama ovisno o veličini neurona spinalnih ganglija. Analiza izražaja fosforilirane alfa-izoforme CaMKII (pCaMKIIα) u neuronima spinalnih ganglija različitoga promjera pokazala je značajno veći izražaj u DM1 štakora, u odnosu na CON-DM1 štakore, u svim analiziranim promjerima neurona (neparni t-test, P<0.05). Usporedbom izražaja tCaMKII, kao i pCaMKIIα u L4 i L5 neuronima spinalnih ganglija DM2 i CON-DM2 životinja nije pronađena značajna razlika između te dvije skupine životinja. Razlike nije bilo kad su sve stanice spinalnih ganglija analizirane zajedno, bez obzira na veličinu, niti kad su stanice analizirane odvojeno, ovisno o promjeru neurona. Izražaj gama-izoforme CaMKII u neuronima spinalnih ganglija nije se promijenio u DM1 i DM2 štakora, u usporedbi s njihovim kontrolama, kao ni izražaj delta-izoforme CaMKII u neuronima spinalnih ganglija u DM1 i DM2 štakora, u usporedbi s njihovim kontrolama.
Zaključak: Povišen izražaj CaMKII u neuronima spinalnoga ganglija u štakorskom modelu dijabetesa tipa 1 ukazuje na moguću patofiziološku ulogu CaMKII u dijabetičkoj neuropatiji. |
| Abstract (english) | Objectives: To investigate whether the expression of CaMKII changes in neurons of the dorsal root ganglia (DRG) of diabetic rats two months after induction of diabetes.
Study design: Prospective study with laboratory animals.
Place of research: Laboratory for Pain Research, University of Split School of Medicine.
Experimental animals: Male Sprague-Dawley rats were used in the study (N=33): 14 in the model of diabetes type 1 (DM1), 7 in the control group of the DM1 model (DM1-CON), 7 in the model of diabetes type 2 (DM2) and 5 in the control group for the DM2 model (CON-DM2). The DM1 model was induced by intraperitoneal injection of 55 mg/kg streptozotocin and DM2 model induced with a combination of low-dose streptozotocin (35 mg / kg) and high-fat diet. Control rats received intraperitoneal injection of citrate buffer. DM1 and CON-DM1 rats were fed with standard chow, whereas DM2 and CON-DM2 animals were fed with high-fat diet. Two months after induction of diabetes rats were sacrificed. L4 and L5 DRGs were analyzed with immunofluorescence.
Main outcome measures: Blood glucose levels, body weight, and expression of enzymes CaMKII and its isoforms (α, γ, δ) in the neurons of the rat DRG.
Results: Expression of total CaMKII (tCaMKII) in DRG neurons 2 months after streptozotocin injection was significantly higher in DM1 rats (16 ± 0.9), compared with CON-DM1 rats (14 ± 2.0) (unpaired t-test, P<0.05). There was a significant difference in the expression of tCaMKII in all neurons, but not in the analyzed subgroups depending on the size of the spinal ganglion neurons. Analysis of the expression of phosphorylated alpha isoform of CaMKII (pCaMKIIα) in DRG neurons showed a significantly higher expression in DM1 rats compared to CON-DM1 rats, in all analyzed diameters of neurons (unpaired t-test, P <0.05). By comparing the expression of tCaMKII and pCaMKIIα in L4 and L5 DRG of DM2 and DM2-CON animals, no significant difference was found between these two groups of animals, regardless of the neuron size. The expression of the gamma and delta isoforms of CaMKII in DRG neurons did not differ in DM1 and DM2 rats compared with their controls at the end of the experiment.
Conclusion: Elevated expression of CaMKII in the DRG neurons of a rat model of type 1 diabetes indicates a possible pathophysiological role of CaMKII in diabetic neuropathy. |
