Attenuation of endoplasmic reticulum stress and mitochondrial injury in kidney with ischemic postconditioning application and trimetazidine treatment

Mahfoudh-Boussaid Asma, Zaouali Mohamed, Hauet Thierry, Hadj-Ayed Kaouther, Miled Abdel-Hédi, Ghoul-Mazgar Sonia, Saidane-Mosbahi Dalila, Rosello-Catafau Joan, Abdennebi, Abdennebi Hassen

Description

Endoplasmic reticulum (ER) and mitochondria have been implicated in the pathology of renal ischemia/reperfusion (I/R). In the present study, we investigated whether the use of ischemic postconditioning (IPostC) and trimetazidine (TMZ) separately or combined could reduce ER stress and mitochondria damage after renal ischemia. Methods Kidneys of Wistar rats were subjected to 60-min of warm ischemia followed by 120-min of reperfusion (I/R group, n = 6), or to 6 cycles of ischemia/reperfusion (10-s each cycle) just after 60-min of warm ischemia (IPostC group, n = 6), or to i.p. injection of TMZ (3 mg/kg) 30-min before ischemia (TMZ group, n = 6), or to the combination of both treatments (IPostC+TMZ group, n = 6). The results of these experimental groups were compared to those of a sham-operated group in which rat renal pedicles were only dissected. Sodium reabsorption rate, creatinine clearance lactate deshydrogenase (LDH) activity in plasma, and concentration of malonedialdehyde (MDA) in tissue were determined. In addition, Western blot analysis was performed to identify the amounts of cytochrome c, c-JunNH2-terminal kinase (JNK), voltage-dependent anion channel (VDAC), glycogen synthase kinase 3-beta (GSK3-β), and ER stress parameters. Results IPostC or/and TMZ significantly decreased cytolysis, oxidative stress and improved renal function in comparison to I/R group. IPostC but not TMZ significantly attenuated ER stress parameters versus I/R group. Indeed, it down-regulated the glucose-regulated protein 78 (GRP78), the activating transcription factor 4 (ATF4), the RNA activated protein kinase (PKR)-like ER kinas (PERK), the X box binding protein-1 (XBP-1) and the caspase12 protein levels. TMZ treatment significantly augmented GSK3-β phosphorylation and reduced levels of cytochrome c and VDAC phosphorylation in comparison to IPostC application. The combination of both treatments gave a synergetic effect. It significantly improved the survival rate, attenuated cytolysis, oxidative stress and improved renal function. Conclusion This study revealed that IPostC protects kidney from I/R injury by suppressing ER stress while the beneficial effects of TMZ are mediated by mitochondria protection. The combination of both treatments ameliorated functional recovery.

Sujets

• Kidney
• Trimetazidine
• Mitocondria

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 17
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Mahfoudh-Boussaid et al. Journal of Biomedical Science 2012, 19:71
http://www.jbiomedsci.com/content/19/1/71
RESEARCH Open Access
Attenuation of endoplasmic reticulum stress and
mitochondrial injury in kidney with ischemic
postconditioning application and trimetazidine
treatment
1 2 3 1 4Asma Mahfoudh-Boussaid , Mohamed Amine Zaouali , Thierry Hauet , Kaouther Hadj-Ayed , Abdel-Hédi Miled ,
5 1 2 1*Sonia Ghoul-Mazgar , Dalila Saidane-Mosbahi , Joan Rosello-Catafau and Hassen Ben Abdennebi
Abstract
Background: Endoplasmic reticulum (ER) and mitochondria have been implicated in the pathology of renal
ischemia/reperfusion (I/R). In the present study, we investigated whether the use of ischemic postconditioning
(IPostC) and trimetazidine (TMZ) separately or combined could reduce ER stress and mitochondria damage after
renal ischemia.
Methods: Kidneys of Wistar rats were subjected to 60-min of warm ischemia followed by 120-min of reperfusion
(I/R group, n=6), or to 6 cycles of ischemia/reperfusion (10-s each cycle) just after 60-min of warm ischemia
(IPostC group, n=6), or to i.p. injection of TMZ (3 mg/kg) 30-min before ischemia (TMZ group, n=6), or to the
combination of both treatments (IPostC+TMZ group, n=6). The results of these experimental groups were
compared to those of a sham-operated group in which rat renal pedicles were only dissected. Sodium reabsorption
rate, creatinine clearance lactate deshydrogenase (LDH) activity in plasma, and concentration of malonedialdehyde
(MDA) in tissue were determined. In addition, Western blot analysis was performed to identify the amounts of
cytochrome c, c-JunNH2-terminal kinase (JNK), voltage-dependent anion channel (VDAC), glycogen synthase kinase
3-beta (GSK3-β), and ER stress parameters.
Results: IPostC or/and TMZ significantly decreased cytolysis, oxidative stress and improved renal function in
comparison to I/R group. IPostC but not TMZ significantly attenuated ER stress parameters versus I/R group. Indeed,
it down-regulated the glucose-regulated protein 78 (GRP78), the activating transcription factor 4 (ATF4), the RNA
activated protein kinase (PKR)-like ER kinas (PERK), the X box binding protein-1 (XBP-1) and the caspase12 protein
levels. TMZ treatment significantly augmented GSK3-β phosphorylation and reduced levels of cytochrome c and
VDAC phosphorylation in comparison to IPostC application. The combination of both treatments gave a synergetic
effect. It significantly improved the survival rate, attenuated cytolysis, oxidative stress and improved renal function.
Conclusion: This study revealed that IPostC protects kidney from I/R injury by suppressing ER stress while the
beneficial effects of TMZ are mediated by mitochondria protection. The combination of both treatments
ameliorated functional recovery.
Keywords: Kidney, Ischemia-reperfusion, Ischemic postconditioning, Trimetazidine, Endoplasmic reticulum stress,
Mitochondria
* Correspondence: [e-mail]
1
Laboratory of human physiology, faculty of pharmacy, university of
Monastir, Rue Avicenne, Monastir 5000, Tunisia
Full list of author information is available at the end of the article
© 2012 Mahfoudh-Boussaid et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of
the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.Mahfoudh-Boussaid et al. Journal of Biomedical Science 2012, 19:71 Page 2 of 14
http://www.jbiomedsci.com/content/19/1/71
Background stress is intense or prolonged and adaptation mechan-
Kidney ischemia reperfusion (I/R) injury, which occurs isms are overwhelmed, the cells trigger an apoptotic
during renal surgery or transplantation, is the major death program [14-16]. The three main mediators
cause of acute renal failure (ARF) [1]. Rapid re- involved in the signaling pathway of the ER stress are
establishment of blood flow is the best way to salvage ATF6 (activated transcription factor 6), IRE1 (inositol re-
organ after ischemic injury, but it may also cause reper- quiring enzyme 1) and PERK (protein kinase RNA
fusion damage. Growing bodies of research currently (PKR)-like ER kinase). Under physiological conditions,
concern the possibility of boosting innate protective these mediators are inactivated by binding to GRP78 in
mechanisms rendering an organ resistant to subsequent the ER membrane. Initiation of UPR needs their release
injury. For example, ischemic preconditioning (IPC) has from GRP78, allowing them to either dimerize or move
been shown to confer protection against a subsequent to other locations within the cell [16].
ischemic attack [2]. IPC is an adaptive response in which It became clear that pharmacological agents could also
brief episodes of ischemia with intermittent reperfusion impart protection when administered prior to the onset
given immediately before the onset of a more sustained of a sustained ischemia. Trimetazidine (TMZ), a well-
warm ischemia attenuates the pathophysiological effect known anti ischemic drug, protects heart [17] and liver
of I/R injury. In the kidney, IPC has been found to di- [18] against I/R through the activation of intracellular
minish post-ischemic damage [3]. However, a more effi- signaling pathways similar to those induced by the IPC.
cient approach is to intervene at the onset of reperfusion, It has also been reported that TMZ protects kidney
the timing of which is under the control of the operator. against the deleterious effects of warm ischemia [19] and
Some results suggest that the first minutes of reperfusion reduces the risk of ARF after kidney surgery [20,21]. Be-
are determinant for defining the final outcome of the kid- sides its metabolic effects, TMZ has been demonstrated
ney after ischemia [1]. In addition, it has been reported to limit oxygen consumption during ischemia, acidosis,
that gradual increase of the blood flow to the ischemic intracellular accumulation of sodium and calcium, and
kidney could decrease ischemic changes [4]. Therefore, thereby maintain the cellular homeostasis [22,23].
the clinical limitations of IPC have led to the emergence The kidney protection conferred by both IPostC and
of a new concept i.e. ischemic postconditioning (IPostC), TMZ through suppression of ER stress remains to be
defined as brief intermittent cycles of ischemia alternat- defined. Thegoals of thepresent studywere: (1)to
ing with reperfusion applied after the ischemic event. compare the effectiveness of two protective strategies
Ischemic postconditioning is an easy and safe ap- namely IPostC and TMZ when used separately or in
proach, which provides protection against I/R injury in combination (2) and to show whether the renal protec-
heart [5], brain [6], liver [7] and kidney [1,4]. It has been tion conferred by IPostC and TMZ involves suppres-
reported that IPostC can reduce cellular apoptosis [8], at- sion of ER stress and mitochondrial impairment in I/R
tenuate renal dysfunction [1], decrease pro-inflammatory kidney.
cytokine release after renal I/R [4] and improve kidney
graft function [9]. However, the cellular mechanisms
underlying the IPostC-induced renal protection against Methods
I/R injury remain unclear and considerable research is Surgical procedure
required for understanding its molecular mechanisms. Male Wistar rats (200–250 g) were anesthetized by keta-
More recently it has been reported that IPostC protects mine (50 mg/Kg, i.p.) and allowed to breathe spontan-
brain and heart from I/R injury by attenuating endoplas- eously. This study respected the European Union
mic reticulum (ER) stress [6,10]. regulations (Directive 86/609/CEE) for animal experi-
Several studies evidenced the pivotal role of ER stress ments. After maintaining the core body temperature at
as a major contributor able to increase the apoptosis and 37°C, a midline laparatomy was performed, and both left
exacerbate cell damage after I/R [11,12]. The ER is a and right renal arteries and veins were exposed. In order
principal site for protein synthesis and folding, calcium to evaluate kidney function, catheters were inserted into
2+
(Ca ) storage, and signaling. Alterations in the ER en- i. the jugular vein to perfuse (Minipuls 3 peristaltic pump,
vironment as occur during renal I/R lead to the perturb- Gilson, France) heated (37°C) mannitol (10%) and heparin
2+
ation of Ca homeostasis and the accumulation of (50 U/I); ii. the carotid artery to measure arterial pressure
misfolded proteins [13]. These disorders induce ER (Pression Monitor BP-1; Pression Instruments, Sarasota,
stress and in turn activate a well-conserved adaptive re- FL) and to collect blood samples collection ; iii. the blad-
sponse, collectively referred to as unfolded protein re- der to collect urine samples. To induce renal ischemia the
sponse (UPR) [14]. The UPR initially reduces the renal pedicles were occluded with non traumatic vascular
amount of native proteins and increases the ability of clamps. Reperfusion was initiated by removal of the
maturation of proteins in the ER. However, when ER clamps.Mahfoudh-Boussaid et al. Journal of Biomedical Science 2012, 19:71 Page 3 of 14
http://www.jbiomedsci.com/content/19/1/71
Figure 1 Experimental protocol. A schematic drawing of the experimental protocol used to determine the effect of ischemic postcondi