This study was aimed at evaluating the protective effect of coenzyme Q10 on L-arginine-induced acute pancreatitis in rats regarding biomarkers and morphologic changes. Thirty-two male Sprague-Dawley rats were divided into 4 equal groups. Control group received intraperitoneal normal saline, while in sham and experimental groups 1 and 2 pancreatitis was induced with L-arginine. E1 and E2 groups were treated with a single dose of 100 and 200 mg/kg Q10, respectively. Serum lipase and amylase, along with pancreas IL-10, IL-1
Acute pancreatitis (AP), noninfectious inflammatory disorder of pancreas, not only is the most common cause of hospital admission among gastrointestinal diseases in many countries [
Oxidative stress is one of the pivotal mechanisms of AP. Excessive reactive oxygen species (ROS) provoke inflammation and development of pancreatitis through zymogen degranulation, granulocyte migration, tissue necrosis, and increased amylase and lipase activity [
Coenzyme Q10 (Ubiquinone), as the only endogenous lipid soluble antioxidant, with a 2,3-dimethoxy-5-methylbenzoquinone nucleus is well established for its antioxidant and anti-inflammatory effects and is the most frequent type of CoQ in human tissue [
Thirty-two male Sprague-Dawley rats, weighing 180–200 g, were obtained from the Pasteur Institute, Tehran, Iran. Rats were housed individually in cages on a 12:12 h light-dark cycle at
Rats were randomly divided into 4 groups (
All rats were sacrificed with an overdose of pentobarbital 24 h after the last injection of L-arginine. Blood samples were obtained by direct intracardiac puncture and stored at −70°C for biochemical analysis. The pancreas (4 rats per group) was quickly removed and fixed in formaldehyde (10%) for histological examination.
Blood samples were centrifuged at 15,000 rpm under 4°C and the plasma was separated by using sterile pipettes. Serum lipase and amylase activity were evaluated with a spectrophotometric technique by the Olympus AU-2700 autoanalyzer (Olympus, Hamburg, Germany) using commercial kits (MAN Company, Tehran, Iran). The results were expressed as U/I.
Serum IL-10, IL-1
The pancreatic tissues (4 rats per group) were removed and were promptly frozen in liquid nitrogen and stored at −70°C until being assayed. Protein estimation was done by the method of Lowry et al. [
The activity of SOD in pancreas was measured using a commercial assay kit (Sigma, Germany), following the manufacturer’s instructions. This assay kit uses a tetrazolium salt for detection of superoxide anions generated by xanthine oxidase and hypoxanthine. These superoxide radicals oxidize hydroxylamine and lead to formation of nitrite, which reacts with naphthalene diamine and sulfanilic acid to produce a colored product. SOD in the sample reduces the overall superoxide anion concentration, thereby lowering the colorimetric signal and absorbance at 550 nm. One unit (U) of SOD was defined as the amount of enzyme needed to produce 50% dismutation of superoxide radical. The activity of SOD was expressed as U/mg of protein.
The GSH content was measured using the 5,5′-dithiobis(2-nitrobenzoic acid)-oxidized GSH (DTNB-GSSG) reductase recycling assay for total glutathione (GSH + GSSG) as described by Tietze [
The MDA content was determined using the thiobarbituric acid (TBA) test [
The pancreatic MPO activity was determined as described [
Paraffin-embedded pancreas tissues were sectioned (5
Data are expressed as mean ± SD. The data was processed by the statistical analysis software SPSS version 16.0 (SPSS Inc., Chicago, IL, USA). Statistical analysis was carried out by one-way analysis of variance (ANOVA) followed by Tukey’s multiple comparison test. Nonparametric data were analyzed by Mann-Whitney
The mean serum amylase level of sham group was significantly higher than the one of control group (
Serum lipase levels in the sham group (
TNF-
Effects of Q10 on the pro- and anti-inflammatory serum cytokines levels in rats. The contents of serum TNF-
MDA and MPO levels in the pancreases of sham group were higher than those of the control group, while SOD and GSH levels were significantly lower than those of the control group (Table
Pancreatic tissue MDA, GSH levels, and SOD activity according to the groups. Data presented as mean ± SD.
MDA (nmol/g) | MPO (U/mg) | SOD (U/mg) | GSH ( | |
---|---|---|---|---|
Control | 24.62 ± 0.87 | 0.10 | 70.37 ± 1.40 | 0.59 ± 0.10 |
Sham | 62.43 ± 1.45 |
0.30 ± 0.03 |
49.68 ± 1.06 |
1.87 ± 0.18 |
E1 | 41.31 ± 0.84 |
0.21 ± 0.01 |
145.56 ± 1.80 |
3.49 ± 0.10 |
E2 | 34.37 ± 0.95 |
0.13 ± 0.01 |
167.31 ± 1.43 |
4.85 ± 0.22 |
Histological examination of pancreas sectioned from L-arginine treated rats revealed tissue damage characterized by edema, inflammatory cell infiltrates, and acinar cell necrosis. Pancreatic edema, inflammation, and necrosis in the sham group were significantly higher than in the control and treatment groups (Figure
Pictures of pancreatic tissue sections in rats (hematoxylin and eosin, magnification ×200). (a) normal morphology, control group; (b) sham group is characterized by interstitial edema, inflammatory cell infiltration, and acinar cell; (c) and (d) treatment with Q10 (E1 and E2 groups, resp.) resulted in lower interstitial edema, less inflammatory cell infiltration, and alleviated acinar cell necrosis.
Total histopathological scores in pancreatic tissues of the rats. Data are expressed as mean ± SD (
As current treatment strategies of AP are mainly limited to supportive care, more effective therapeutic options should be developed for better management of this disorder. Thus, in this study we evaluated the effects of Q10, a ubiquitous radical-scavenging antioxidant present in most eukaryotic cells, on a rodent AP model induced by L-arginine. Our data signified that the pharmacological activation of Q10 in acinar cells can result in not only a remarkable reinforcement of antioxidant defense system but also a significant reduction of inflammatory mediators. Previously, many studies have indicated the role of impaired Q10 bioavailability or biosynthesis in several diseases and also evidently demonstrated favorable outcomes of Q10 supplementation in various disorders and deficiencies [
In the present study, results are in favor of significant protective effect of Q10 on rising of serum amylase and lipase activity, both dependent on treatment dosage. Serum lipase or amylase activities, most commonly used biomarkers in AP, are at least tripled compared to upper limit of normal; however their serum levels may not be dependent on pancreatitis severity [
In addition, our findings demonstrated decreased proinflammatory TNF-
Peroxidation of membrane lipids by ROS releases toxic byproducts such as MDA [
Attempts to counteract the aforementioned complications of AP by exploiting various antioxidants have provided mixed results. To the best of our knowledge, there is no similar experiment, which has dealt with impact of Q10 on AP. Herein we shortly review previous paper on various antioxidants.
Evaluation of anti-inflammatory and antioxidative effects of lycopene on severe AP in both in vivo and in vitro models by Lv et al. [
Nuclear factor-erythroid-2-related factor (Nrf2), a regulator of detoxifying molecules and cellular antioxidants, can be activated by dh404. In a study by Robles et al., treatment with synthetic triterpenoid RTA dh404 (CDDO-dhTFEA) in rat pancreas resulted in significant prevention of acinar architecture damage, reduced inflammatory cell infiltration, perilobar edema, and necrosis as well as decreased amylase and MDA, which was compatible with our study. Besides, elevated antioxidant and lower inflammatory mediators’ expression with pronounced cellular viability against oxidative stress was observed [
In an investigation of AP induced liver injury in rats via antioxidant response, Bakır et al. used carvacrol, the essential oil of
Considering that in previous animal models of AP N-acetylcysteine could decrease the severity of disease, Milewski et al. studied treatment with N-acetylcysteine for AP as one of the most severe and common complications in postendoscopic retrograde cholangiopancreatography (ERCP) patients. However, N-acetylcysteine failed to show substantial preventive effects in such cases [
A study in Germany on patients with AP yielded supportive results in favor of advantage of selenium therapy in terms of decreased morbidity and mortality and the number of necessary operations.
Nonetheless, as administration of one or few exogenous compounds cannot compensate for complete natural antioxidant defense system which consists of numerous detoxifying enzymes, therefore, the complex endogenous antioxidant system requires more than only a few aiding compounds to be boosted [
Despite fundamental support for the basic role of ROS influx and inflammatory cascades mediated by oxidative stress in AP, currently firm clinical verification regarding clear potential of antioxidant supplementation of AP is still lacking. As several different factors might be involved in induction of AP, which ultimately result in diverse physiologic complications, treatment with combination modalities can be of higher value in clinical settings in comparison to single agent approaches [
Based upon the results of the present study, administration of coenzyme Q10 diminished inflammation by lowering inflammatory mediators and oxidative stress by escalating expression of crucial antioxidant enzymes in experimental AP model. Hence, Q10 seems to be a promising antioxidant with significant therapeutic effects in amelioration of histologic damage via modulation of cytokines and oxidative markers and reduction in plasma levels of pancreatic enzymes. Further studies are necessary to determine the clinical efficacy and detailed mechanisms underlying the beneficial properties of Q10 which might also prove to be targets of other antioxidants with future therapeutic potentials.
The authors declare that they have no competing interests.