Hyperbaric oxygen and N-acetylcysteine treatment in L-arginine-induced acute pancreatitis in rats

N-Acetylcysteine enhances the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation in rats with severe acute pancreatitis

BACKGROUND

Severe acute pancreatitis (SAP) is a high mortality disease, for which there is a lack of effective therapies. Previous research has demonstrated that bone marrow-derived mesenchymal stem cells (BMSCs), which have immunomodulatory and antioxidant properties, have potential for the treatment of SAP. It remains unclear, however, whether the free radical scavenger N-acetylcysteine (NAC) can enhance the therapeutic efficacy of BMSC transplantation in SAP. In this study, we investigated the effect of combining treatment with NAC and BMSCs in a rat model of SAP.

METHODS

SAP was induced by injection of sodium taurocholate into the pancreatic duct and, after successful induction of SAP, the rats were treated with BMSCs and NAC, either singly or in combination.

RESULTS

After 3 days, serum levels of amylase, proinflammatory factors, malondialdehyde, and reactive oxygen species were significantly decreased in animals treated with BMSCs or NAC, compared with vehicle-treated animals. In contrast, total glutathione, superoxide dismutase and catalase were markedly increased after treatment with BMSCs or NAC. However, oxidative stress markers and inflammatory factors were significantly improved in the SAP + BMSCs + NAC group compared with those in the SAP + NAC group and the SAP + BMSCs group.

CONCLUSIONS

Combined NAC and BMSC therapy was found to alleviate oxidative stress damage to the pancreas and to inhibit the inflammatory response to a significantly greater extent than single therapy with either BMSCs or NAC. Because NAC enhances the therapeutic efficacy of BMSC transplantation in a rat model of SAP, combined therapy may provide a promising new approach for the treatment of SAP.

Dynamic thiol/disulphide homeostasis in acute pancreatitis

BACKGROUND/AIMS

The dynamic thiol/disulfide homeostasis plays pivotal roles in many physiological mechanisms in an organism. We aimed to investigate whether dynamic thiol/disulfide homeostasis changes among patients with acute pancreatitis.

MATERIALS AND METHODS

This prospective trial contained 45 patients with acute pancreatitis and 45 sex-and age-matched healthy volunteers as control group. Thiol/disulfide homeostasis parameters were measured by a novel and automated assay, and detected results were compared between the two groups.

RESULTS

Disulfide/total thiol percent ratio and disulfide/native thiol percent ratios were significantly higher in acute pancreatitis group; besides the native thiol, total thiol levels and native thiol/total thiol percent ratios were significantly lower (for all p < 0.001).

CONCLUSION

The thiol/disulfide homeostasis is impaired in acute pancreatitis with a shift toward the oxidative status, and this deficiency might be a pathogenic factor in acute pancreatitis. The correction of this thiol/disulfide imbalance may be a new target in the management of acute pancreatitis.

Early differential diagnosis of the severity of acute pancreatitis

There is a great need for early verification of the severity of acute pancreatitis (AP). The early stage of pathogenesis of AP is characterized by endothelial dysfunction which could be determined by wavelet analysis of skin temperature (WAST) technique. The aim is to investigate whether the dysregulation of microvascular tone caused by endothelial dysfunction and detected by WAST can be a significant indicator in early differential diagnosis of AP severity. The WAST performed in the frequency range of 0.0095-0.02 Hz during the contralateral cold test. Forty nine patients with AP aged 19-65 participated in this study. The control group included 12 healthy volunteers aged 20-65. Dysregulation of vascular tone during the contralateral cold test was observed in all patients with AP. The basal amplitudes of skin temperature oscillations in patients with AP were much lower than in healthy volunteers and progressively decreased as the disease severity increased. In patients with mild and moderate AP only the vasodilator component is destroyed, but vasoconstriction still operates. In patients with severe AP both mechanisms of endothelial vascular tone regulation are destroyed. Patients with AP have abnormal microvascular reactions related to the endothelial mechanism of vascular tone regulation. Based on the initial values of amplitudes and the indices of vasoconstriction and postcold vasodilatation, the WAST method makes it possible to evaluate two related but different characteristics of the endothelial dysfunction in patients with AP on admission which can be a significant indicator in early differential diagnosis of AP severity.

Apigenin Attenuates Inflammation in Experimentally Induced Acute Pancreatitis-Associated Lung Injury

BACKGROUND

Acute pancreatitis is associated with acute lung injury. The aim of the present study is to evaluate alterations of lungs in an experimental model of acute pancreatitis (AP) following both bilio-pancreatic duct obstruction close to the duodenum. Acute pancreatitis is a common disease with significant mortality. This situation makes the need of finding protective factors for the lung parenchyma, imperative. In the present study there is an effort to clarify the role of apigenin, a substance which is well known for its antioxidant and anti-inflammatory effects, on lung injury, following acute pancreatitis in rats.

MATERIALS AND METHODS

In the present study, 126 male Wistar-type rats 3-4 months old and 220-350 g weight were used. At time 0 we randomly assigned the following groups: Group Sham: Rats were subjected to virtual surgery. Group Control: Rats were subjected to surgery for induction of acute pancreatitis. Group Apigenin: Rats were subjected to surgery for induction of acute pancreatitis and enteral feeding with apigenin. Immunochemistry for TNF-α and IL-6 as well as MPO activity were measured at predetermined time intervals 6, 12, 24, 48, and 72 h, in order to evaluate architectural disturbances of the lung tissue.

RESULTS

From the pathological reports we realized that comparing the control group with the apigenin group, there is an improvement of lung tissue damage following apigenin administration, with statistical significance. Apigenin reduces most histopathological alterations of the pulmonary tissue, reduces MPO and TNF-α activity at 48 hours and, furthermore, reduces IL-6 activity at 72 hours post-administration.

CONCLUSIONS

Oral Apigenin administration in rats, following experimental induced acute pancreatitis, seems to be protective on the lung tissue. Apigenin administration to humans could potentially ameliorate acute lung injuries. However, special caution is required for humans' use, as more detailed studies are needed.

A new combination therapy in severe acute pancreatitis--hyperbaric oxygen plus 3-aminobenzamide: an experimental study

OBJECTIVES

This study was designed to evaluate effects of hyperbaric oxygen (HBO) plus 3-aminobenzamide (3-AB) cotreatment on tissue oxidative stress parameters (TOSp), tissue histopathology scores (THSc), and bacterial translocations (Bact-Trans) in an experimental model of severe acute pancreatitis (AP).

METHODS

Seventy-five Sprague-Dawley rats were randomized into 5 groups. Group 1 received sham. Severe AP was induced by intraductal taurocholate infusion and then group 2 received saline, group 3 received 3-AB, group 4 received 3-AB plus HBO, and group 5 received HBO. 3-Aminobenzamide (10 mg/kg per day, once daily, intraperitoneal) and saline (1 mL/kg) were started right after the induction, whereas HBO (2,8 atm pressure, BID, 90 minutes each) was started at the sixth hour. The rats were euthanized at the 54th hour, and TOSp, THSc, and Bact-Trans were studied.

RESULTS

In treatment groups 3 and 5, Bact-Trans (P < 0.05, P < 0.05), TOSp (P < 0.05, P < 0.05), and THSc (P < 0.001, P < 0.001) were significantly lower than controls. In addition to these findings, group 4 (cotreatment) showed the most significant effect on Bact-Trans and THSc (P < 0.001, P < 0.001) and also better in TOSp (P < 0.02).

CONCLUSIONS

Poly(ADP-ribose) polymerase inhibition by 3-AB and HBO treatment alone was effective in the course of severe AP, and favorable with cotreatment because of the improved cascades of inflammatory process by different aspects.

The apoptosis of peripheral blood lymphocytes promoted by hyperbaric oxygen treatment contributes to attenuate the severity of early stage acute pancreatitis in rats

The aim of this study was to investigate the immunoregulatory effects of hyperbaric oxygen (HBO) via promoting the apoptosis of peripheral blood lymphocytes (PBLs) to attenuate the severity of early stage acute pancreatitis (AP) in rats. Additionally, the persistence of the HBO treatment effects was evaluated. One hundred and twenty male Wistar rats were randomized into four groups: sham, AP, AP + normobaric oxygen (NBO), and AP + HBO. Each group consisted of 30 rats. Four hours after the induction of AP, the 30 rats in the AP + NBO group were given normobaric oxygen treatment with 100 % oxygen at 1 atm for 90 min. The 30 rats in the AP + HBO group received 100 % oxygen at 2.5 atm for 90 min, with a compression/decompression time of 15 min. The 30 rats in the AP group remained untreated. At 6, 12, and 24 h after the induction of AP, surviving rats from each group were sacrificed, and the blood and tissue samples were collected for the following measurements: the partial pressure of oxygen (PaO2) and oxygen saturation (SaO2) of the arterial blood, the levels of serum amylase, lipase, interleukin-2 (IL-2), interferon-γ (IFN-γ), interleukin-10 (IL-10), hepatocyte growth factor (HGF), and reactive oxygen species (ROS), and the mitochondrial membrane potential (∆Ψm) of the PBLs. The expression levels of procaspase-3, caspase-3, procaspase-9, and caspase-9 were also evaluated in the PBLs. Additionally, the apoptosis of PBLs was assessed, and the pancreatic tissues were subjected to a histopathological analysis by pathological grading and scoring. The histopathology of the lung, liver, kidney, duodenum, and heart was also analyzed at 12 h after the induction of AP. Significant differences were found at 6 and 12 h after AP induction. The HBO treatment significantly elevated the PaO2 and SaO2 levels, and the ROS levels in the PBLs. Additionally, HBO downregulated the levels of amylase and lipase. The HBO treatment also reduced the ∆Ψm levels, upregulated the expression of caspase-3 and caspase-9, and increased the apoptosis rate of the PBLs. Moreover, the HBO treatment decreased the serum concentrations of IL-2, IFN-γ and HGF, and reduced the pathological scores of the pancreatic tissue. The histopathological changes of the lung, liver, kidney, duodenum, and heart were also improved. A significant elevation of IL-10 occurred only at the 12-h time point. However, no obvious differences were found at the 24-h time point. This study demonstrated that the HBO treatment can promote the apoptosis of PBLs via a mitochondrial-dependent pathway and inhibit the inflammatory response. These immunoregulatory effects may play an important therapeutic role in attenuating the severity of early stage AP. The repeated administration of HBO or the use of HBO in combination with other approaches may further improve outcomes.

Recent advances in the investigation of pancreatic inflammation induced by large doses of basic amino acids in rodents

It has been known for approximately 30 years that large doses of the semi-essential basic amino acid L-arginine induce severe pancreatic inflammation in rats. Recently, it has been demonstrated that L-arginine can also induce pancreatitis in mice. Moreover, other basic amino acids like L-ornithine and L-lysine can cause exocrine pancreatic damage without affecting the endocrine parenchyma and the ducts in rats. The utilization of these noninvasive severe basic amino acid-induced pancreatitis models is becoming increasingly popular and appreciated as these models nicely reproduce most laboratory and morphological features of human pancreatitis. Consequently, the investigation of basic amino acid-induced pancreatitis may offer us a better understanding of the pathogenesis and possible treatment options of the human disease.

N-acetylcysteine alleviated silica-induced lung fibrosis in rats by down-regulation of ROS and mitochondrial apoptosis signaling

Reactive oxygen species (ROS) is a normal metabolic product of cellular respiration, but too much ROS can induce cell apoptosis. Here, we used N-acetylcysteine (NAC) to inhibit ROS activity to explore the effects of NAC on silica-induced pulmonary fibrosis in rats and provide evidence for study on the mechanism of silicosis. 24 adult male Sprague-Dawley rats weighing 180-220 g were randomly divided into three groups with eight rats in each group. Silicosis model group and NAC group were adopted non-tracheal exposure method of disposable intrapulmonary injection of 50 g/L, silica suspension 1 mL to establish animal silicosis model, NAC group treated with 600 mg/kg NAC by gavage from the right day of modeling, all animals were sacrificed after 28 days. The level of ROS contents and mitochondrial transmembrane potential changes of AM, the mRNA expression level of type I and type III procollagen, cytochrome C, cysteinyl aspartate specific protease-9 and caspase-3 were detected. The severity of pathological changes and pulmonary fibrosis were observed by pathologic specimens. It was showed that ROS contents and MTP changes were lower in the NAC group compared with the silicosis model group, other indexes were lower in the NAC group than the model group, but higher than those of the control group, the degree of lung fibrotic lesions observed from the pathological slices showed the same trend. These data indicated that NAC can reduce ROS content of AM in silica exposure rats, the mitochondrial apoptosis pathway can also be inhibited, the severity of pulmonary fibrosis alleviated as a result.

Experimental and clinical evidence of antioxidant therapy in acute pancreatitis

Oxidative stress has been shown to play an important role in the pathogenesis of acute pancreatitis (AP). Antioxidants, alone or in combination with conventional therapy, should improve oxidative-stress-induced organ damage and therefore accelerate the rate of recovery. In recent years, substantial amounts of data about the efficiency of antioxidants against oxidative damage have been obtained from experiments with rodents. Some of these antioxidants have been found beneficial in the treatment of AP in humans; however, at present there is insufficient clinical data to support the benefits of antioxidants, alone or in combination with conventional therapy, in the management of AP in humans. Conflicting results obtained from experimental animals and humans may represent distinct pathophysiological mechanisms mediating tissue injury in different species. Further detailed studies should be done to clarify the exact mechanisms of tissue injury in human AP. Herein I tried to review the existing experimental and clinical studies on AP in order to determine the efficiency of antioxidants. The use of antioxidant enriched nutrition is a potential direction of clinical research in AP given the lack of clues about the efficiency and safety of antioxidant usage in patients with AP.