Role of allopurinol on oxidative stress in caustic burn: cure for stricture?

Role of N-acetylcysteine and vitamin B complex in improving outcomes of corrosive ingestion

Background

Corrosive ingestion remains a worldwide public health problem. To date, there are no specific medications with approved efficacy in reducing gastrointestinal injury progression following corrosive ingestion.

Aim

The current study assessed the efficacy of N-acetylcysteine (NAC) and vitamin B complex as adjuvant therapy in improving the outcome of patients with corrosive ingestion.

Subjects and methods

The study included 92 patients with acute corrosive ingestion admitted to Alexandria Poison Center. Patients were distributed into four equal-sized groups and managed as such; Group I received the standard treatment protocol. The other three groups received IV antioxidants in addition to the standard treatment; Group II received NAC, Group III received vitamin B complex, and Group IV received both NAC and vitamin B complex. To assess occurrence of delayed complications, barium swallow and meal were done 21 days after acute corrosive ingestion, and every patient was followed up for one year.

Results

Start of oral intake was earliest among patients in Group II, and as a result, the need for parenteral nutrition decreased significantly with a subsequent decrease in duration of hospitalization. The highest percentage of patients showing normal findings of barium swallow and meal was among the two groups that received NAC (72.7% in Group II and 77.8% in Group IV). Group IV patients who received NAC and vitamin B complex had no esophageal strictures with improved outcomes.

Conclusion

NAC and vitamin B complex enhanced recovery in the acute stage, in addition to prevention of delayed complications, especially esophageal strictures.

Highlights

Acute corrosive ingestion is associated with high morbidity because of its catastrophic presentation and lifelong complications.This study was conducted on 92 patients admitted to Alexandria Poison Center (APC).IV NAC significantly decreased the time needed for starting oral intake after acute corrosive ingestion and consequently, the need for parenteral nutrition and duration of hospitalization.No patients suffered from esophageal strictures in the group which received both IV NAC and vitamin B complex.Both NAC and vitamin B complex improved the outcome of patients after ingestion of corrosives whether acids or alkalis.

Protective effect of bromelain on corrosive burn in rats

INTRODUCTION

In some cases, the tongue and oesophagus tissues are damaged by the corrosive burn. Surgical interventions may cause scar formation, and severe burns treatment methods are limited. This study aims to investigate bromelain, a phytotherapeutic product, on the corrosive burn as a non-surgical option and as an adjunctive therapy, insofar as the treatment of corrosive wounds is not limited only to the treatment of oxidative stress and inflammatory reactions.

METHODS

On the tongues of Wistar albino rats, chemically produced oral ulcers were created by topical application of NaOH (40%) solution, and in the distal oesophagus same mixture was applied to produce a corrosive oesophageal burn. For a week, they were treated orally by bromelain (100 mg/kg/day) or saline solution. At the end of seven days, animals were decapitated to remove the tongue and oesophagus, and blood samples were collected to obtain serum. Myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), interleukin-1 beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) concentrations were measured in serum, and luminol and lucigenin chemiluminescence (CL) were measured in tissue samples.

RESULTS

MDA and CL values were significantly increased, and GSH levels in tissue significantly decreased due to the corrosive burns. Saline treated corrosive burn group measured higher in the serum cytokines in according to the control group.

CONCLUSIONS

Bromelain administration decreased oxidant and inflammatory parameters and increased antioxidant levels in NaOH-induced corrosive burns. Thus, we concluded that bromelain may protect the tongue and oesophagus tissues with its anti-inflammatory and antioxidant effects.

Halofuginone improves caustic-induced oxidative injury of esophagus in rats

BACKGROUND

The aim of this study is to evaluate the anti-inflammatory and anti-fibrotic effects of halofuginone in caustic esophageal burn injury in rats.

MATERIALS AND METHODS

Corrosive esophageal injury (CEI) was produced in male Wistar albino rats by instilling NaOH solution (1 ml, 37.5%) into the distal esophagus. Rats were decapitated on the 3rd day (early group) or 28th day (late group), and treated daily with either saline or halofuginone (100 µg/kg/day; i.p.), continued on alternate days after the third day. Histopathological evaluation and measurement of nitric oxide (NO), peroxynitrite (ONOO-) and oxygen-derived radicals by chemiluminescence (CL) were made in the distal 2 cm of the esophagus. Non-irrigated proximal esophageal samples were assessed for the levels of nuclear factor (NF)-κB, caspase-3, glutathione (GSH), malondialdehyde (MDA) and myeloperoxidase (MPO) activity.

RESULTS

GSH, MDA, NF-κB and caspase-3 levels, and MPO activity in the proximal esophagus were not different among groups. Increased number of TUNEL (+) cells in the irrigated esophagus of the early and late caustic injury groups was reduced by halofuginone treatment. High microscopic damage scores in both early and late CEI groups were decreased with halofuginone treatment. NO, ONOO- and CL levels, which were elevated in the saline-treated early CEI group, were reduced by halofuginone treatment, but reduced NO and ONOO- levels in the late period of saline-treated group were increased by halofuginone.

CONCLUSION

In addition to its anti-fibrotic effects, current findings demonstrate that halofuginone exerts antioxidant and anti-apoptotic actions and supports therapeutic potential for halofuginone in CEI-induced oxidative stress.

Beneficial effects of Ankaferd Blood Stopper on caustic esophageal injuries: an experimental model

Ankaferd Blood Stopper (ABS) is an herbal extract that enhances mucosal healing. The aim of this study was to investigate the efficacy of ABS on the healing of the esophagus and prevention of stricture development after esophageal caustic injuries in rats. The study included 50 rats. Rats were divided into five groups: group 1 (no injury, sham surgery), group 2 (injury + no ABS + study after 2 weeks of injury), group 3 (injury + ABS + study after 2 weeks of injury), group 4 (injury + no ABS + study after 4 weeks of injury), and group 5 (injury + ABS + study after 4 weeks of injury). Standard esophageal burn injury was created by applying 50% NaOH solution to distal esophagus of about 1.5 cm. To rats in the sham group, isotonic solution was given instead of NaOH. ABS (2 mL/day) was given via oral route to group 3 and 5 rats. Fourteen days (group 2 and 3) and 28 days (group 4 and 5) later, all the live rats were killed. The distal esophageal segments of all rats were removed and divided into two equal parts for biochemical and histopathological examination. Mortality rate, weight changes, inflammation, stenosis index (SI), and biochemical measurements were evaluated. The SI was found as 0.31 ± 0.03 in group 1, 0.533 ± 0.240 in group 2, 0.568 ± 0.371 in group 3, 0.523 ± 0.164 in group 4, and 0.28 ± 0.03 in group 5. The SI and inflammation in ABS-treatment group 5 was significantly lower than that in non-treatment group 4 (P= 0.005). There were no significant differences between inflammation and SI among other groups. The mortality rate was 14.2% in group 1, 37.5% in untreated group 2, 14.2% in ABS-treated group 3, 80% in untreated group 4, and 33.3% in ABS-treated group 5. The mortality rate in group 4 was significantly higher than other groups (P= 0.025). Decrease rates in mean body weights of the groups were as follows: group 1, 1%; group 2, 15%; group 3, 14%; group 4, 46%; and group 5, 15%. Biochemical tests other than albumin and creatinine were comparable among the groups. Treatment with ABS prevents inflammation, scar formation, weight loss, and mortality in esophageal caustic injuries. Additional studies to evaluate the clinical benefits of ABS in esophageal caustic injury are recommended.

A combination of ischemic preconditioning and allopurinol protects against ischemic injury through a nitric oxide-dependent mechanism

This study examined the cytoprotective mechanisms of a combination of ischemic preconditioning (IPC) and allopurinol against liver injury caused by ischemia/reperfusion (I/R). Allopurinol (50mg/kg) was intraperitoneally administered 18 and 1h before sustained ischemia. A rat liver was preconditioned by 10 min of ischemia, followed by 10 min of reperfusion, and then subjected to 90 min of ischemia, followed by 5h of reperfusion. Rats were pretreated with adenosine deaminase (ADA), 3,7-dimethyl-1-[2-propargyl]-xanthine (DMPX), and N-nitro-l-arginine methyl ester (l-NAME) before IPC. Hepatic nitrite and nitrate and eNOS protein expression levels were increased by the combination of IPC and allopurinol. This increase was attenuated by ADA, DMPX, and l-NAME. I/R induced an increase in alanine aminotransferase activity, whereas it decreased the hepatic glutathione level. A combination of IPC and allopurinol attenuated these changes, which were abolished by ADA, DMPX, and l-NAME. The increase in the liver wet weight-to-dry weight ratio after I/R was attenuated by the combination of IPC and allopurinol. In contrast, hepatic bile flow was decreased after I/R, which was attenuated by the combination of IPC and allopurinol. These changes were restored by l-NAME. I/R induced a decrease in the level of mitochondrial dehydrogenase, whereas it increased mitochondrial swelling. A combination of IPC and allopurinol attenuated these changes, which were restored by ADA, DMPX, and l-NAME. Our findings suggest that a combination of IPC and allopurinol reduces post-ischemic hepatic injury by enhancing NO generation.

Hydrogen-rich saline protects against acute lung injury induced by extensive burn in rat model

Hydrogen has been reported to selectively quench detrimental reactive oxygen species, particularly hydroxyl radical, and to prevent myocardial or hepatic ischemia/reperfusion injury in multiple models. The aim of this study is to investigate whether hydrogen protects against severe burn-induced acute lung injury in rats. Rats were divided into four groups: sham plus normal saline, burn injury plus normal saline, burn injury plus hydrogen-rich saline, and burn injury plus edaravone. Animals were given full-thickness burn wounds (30% TBSA) using boiling water, except the sham group that was treated with room temperature water. The rats in hydrogen group received 5 ml/kg of hydrogen-rich saline, sham and burn controls obtained the same amount of saline, and the edaravone group was treated with 9 mg/kg of edaravone in saline. Lactated Ringer's solution was given at 6 hours postburn. The lungs were harvested 12 hours postburn for laboratory investigations. Severe burns with delayed resuscitation rapidly caused lung edema and impaired oxygenation in rats. These dysfunctions were ameliorated by administration of hydrogen-rich saline or edaravone. When compared with the burn injury plus normal saline group, hydrogen-rich saline or edaravone group significantly attenuated the pulmonary oxidative products, such as malondialdehyde, carbonyl, and 8-hydroxy-2'-deoxyguanosine. Furthermore, administration of hydrogen-rich saline or edaravone dramatically reduced the pulmonary levels of pulmonary inflammation mediators and myeloperoxidase. Intraperitoneal administration of hydrogen-rich saline improves pulmonary function by reducing oxidative stress and inflammatory response in severe burn-induced acute lung injury.

Development of a model of benign esophageal stricture in rats: the optimal concentration of sodium hydroxide for stricture formation

PURPOSE

To investigate the optimal concentration of sodium hydroxide (NaOH) on esophageal stricture formation in rats to establish an animal model of benign esophageal stricture (BES).

METHODS

Corrosive esophageal burn was produced by internal application of different concentrations of NaOH to the distal esophagus in rats. As much as 66 male rats were randomly divided into eight groups: Group A (control, n = 6), Group B (sham-operated group, n = 6), Group C (5% NaOH, n = 8), Group D (10% NaOH, n = 8), Group E (20% NaOH, n = 8), Group F (30% NaOH, n = 10), Group G (40% NaOH, n = 14), and Group H (50% NaOH, n = 6). Surviving rats were killed at 28 days. The survival rate, body weight gain, symptoms, and histopathological changes were assessed.

RESULTS

The mortality rate was high in Groups G and H (73 and 67%). The prevalence of symptoms of BES was 43% in Groups D and E, 50% in Group F, 75% in Group G, and 100% in Group H. Statistically significant stricture formation of the esophagus was observed in Groups F and G. The degree of tissue damage was significantly higher in Groups E, F, and G.

CONCLUSION

A high concentration of NaOH of 30% was required to establish a survivable BES model in rats.

Allopurinol in dermatology

Off-label use is common in dermatology, and is inevitable for rare cutaneous diseases such as perforating dermatosis. Allopurinol is traditionally considered to be a drug for hyperuricemia only, but the recent demonstration of its efficacy in congestive heart failure has spurred renewed interest in its application in other clinical specialties. In dermatology, allopurinol is best known for its severe cutaneous adverse reactions. Recent genomic studies conducted in Taiwan have discovered useful HLA markers for determining the susceptibility of Stevens-Johnson syndrome and toxic epidermal necrolysis associated with allopurinol. Allopurinol has also been used in a number of dermatologic disorders including acquired reactive perforating collagenosis, sarcoidosis, psoriasis and granulomas caused by methacrylate microspheres, silicon and tattoos. Allopurinol may express its therapeutic effects via its antioxidation or anti-inflammatory properties, or its ability to improve vascular function.

Protective effects of ibuprofen against caustic esophageal burn injury in rats

PURPOSE

The aim of this study was to investigate the efficacy of ibuprofen on the healing of esophagus and the prevention of stricture development after esophageal caustic injuries in rats.

MATERIALS AND METHODS

Rats were divided into three groups as: group 1(sham), group 2(esophageal burn injury), group 3(injury + ibuprofen). In groups 2 and 3, a standard esophageal burn injury was created by applying 10% NaOH solution to distal esophagus of about 3 cm. To rats in the sham group, isotonic solution was given instead of NaOH. Ibuprofen (90 mg/kg/day) was given via oral route to group 3 rats. Normal saline as placebo was given via the same route to rats in groups 1 and 2. 28 days later, all the live rats were killed. The distal esophageal segments of all rats were removed and divided into two equal parts for biochemical and histopathologic examination. In the tissue samples, biochemically hydroxyproline and histopathologically collagen content and stenosis indices were evaluated for efficacy of treatment.

RESULTS

The hydroxyproline level (microg/mg wet tissue) in the groups was 1.54 +/- 0.08, 4.82 +/- 0.60, and 3.28 +/- 0.27, respectively. The hydroxyproline level increased significantly in group 2 compared with group 1 (P < 0.01). Although the hydroxyproline level was significantly increased in group 3 compared with group 1, it decreased significantly in group 3 compared with group 2 (P < 0.05) by treatment of ibuprofen. In group 3, the collagen content score (1.50 +/- 0.26) was significantly lower than in group 2 (2.62 +/- 0.37) (P < 0.05). The stenosis index was found as 0.37 +/- 0.02 in group 1, 0.84 +/- 0.02 in group 2, and 0.67 +/- 0.03 in group 3. The stenosis index in group 2 was significantly higher than group 1 and group 3 (P < 0.01). Although the stenosis index was significantly higher than in group 1, a significant decrease in stenosis index was found in group 3 compared with group 2, by ibuprofen treatment (P < 0.01).

CONCLUSION

Based on these results, we concluded that the treatment with ibuprofen in acute phase esophageal burn injury has beneficial effects on healing of esophagus and may decrease the stricture formation. For these reasons, ibuprofen may effectively be used in the acute phase treatment of caustic esophagus injury and after esophageal dilatation procedures.

The protective effect of erythropoietin on the acute phase of corrosive esophageal burns in a rat model

INTRODUCTION

An experimental study was conducted to investigate the effects of erythropoietin on the acute phase of esophageal burn damage induced by sodium hydroxide.

MATERIALS AND METHODS

A standard esophageal alkaline burn was produced by the application of 10% sodium hydroxide to the distal esophagus in an in vivo rat model. Fifty-six female rats were allocated into three groups: Group BC (baseline control, n = 8) rats were uninjured and untreated, Group PC (positive control, n = 24) rats were injured but untreated and Group EPO (erythropoietin-treated, n = 24) rats were injured and given subcutaneous erythropoietin (1,000 IU/kg per day), 15 min, 24, and 48 h after administration of the NaOH solution. Six animals from Group PC and six from Group EPO were killed at 4, 24, 48, and 72 h after application of NaOH to the esophagus. All of animals in Group BC were killed 4 h after exposure to 0.9% NaCl. Oxidative damage was assessed by measuring levels of malondialdehyde (MDA) and nitric oxide (NO), and activities of superoxide dismutase (SOD) and catalase (CAT) in homogenized samples of esophageal tissue. Histologic damage to esophageal tissue was scored by a single pathologist blind to groups.

RESULTS

MDA levels in the BC and EPO groups were significantly lower than those in the PC group (p < 0.05). CAT and SOD activities, and NO levels in the BC and EPO groups were significantly higher than in the PC group (p < 0.05). Esophageal tissue damage measured at 4, 24, 48, and 72 h after NaOH application was significantly less in the EPO group than in the PC group (p < 0.05).

CONCLUSIONS

When administered early after an esophageal burn induced by 10% sodium hydroxide in this rat model, erythropoietin significantly attenuated oxidative damage, as measured by biochemical markers and histologic scoring.

The role of allopurinol on oxidative stress in experimental hyperthyroidism

AIM

During hyperthyroidism, production of free oxygen radicals derives, where xanthine oxidase may also play an important role. Allopurinol, a xanthine oxidase inhibitor, has a significant effect on thyrotoxicosis-related oxidative stress. However, the relationship between thyroid hormones, oxidative stress parameters and allopurinol remains to be explored.

METHODS

Forty-two Wistar albino rats were divided into three groups. Rats in group A served as negative controls, while group B had untreated thyrotoxicosis and group C received allopurinol. Hyperthyroidism was induced by daily 0.2 mg/kg L-thyroxine intraperitoneally in groups B and C; 40 mg/kg allopurinol were given daily intraperitoneally. Efficacy of the treatment was assessed after 72 h and 21 days, by measuring serum xanthine oxidase (XO), malondialdehyde (MDA), glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx) and nitric oxide derivates (NO*x).

RESULTS

In both time periods, serum XO, MDA, GSH and NO*x levels were significantly increased after thyroid hormone induction (p<0.05). Levels of XO, MDA and NO*x decreased with allopurinol treatment (p<0.05). There was a remarkable decrease in triiodothyronine levels in group C after 72 h (p<0.05), and in both triiodothyronine and thyroxine levels in group C after 21 days (p<0.05). There was no difference between groups B and C in means of serum GSH, GR and GPx levels (p>0.05).

CONCLUSIONS

This study suggests an association between allopurinol and the biosynthesis of thyroid hormones. Allopurinol prevents the hyperthyroid state, which is mediated predominantly by triiodothyronine and not by XO. This issue has to be questioned in further studies where allopurinol is administered in control subjects.