Nicotine withdrawal alleviates acetic acid-induced gastric injury in rats

Protective Effect of Nicotine on Sepsis-Induced Oxidative Multiorgan Damage: Role of Neutrophils

Introduction

Despite its adverse health consequences, tobacco smoking is associated with lower incidence of several neurodegenerative and inflammatory diseases. The present study is aimed to show the effects of nicotine, major tobacco constituent, on five organs targeted by sepsis.

Methods

Male Wistar albino rats received tap water with (5mg/kg) or without nicotine for 14 days. Under ketamine anesthesia, sepsis (n = 50) was induced by ligation and puncture of the cecum, while sham group (n = 8) had only laparotomy. In other rats, nicotine drink was withdrawn for 5 days before sepsis induction, while in acute nicotine group, rats were injected with nicotine (30mg/kg, i.p.) before sepsis, but had no oral intake. Rats were decapitated 24 hours after surgery to obtain lung, liver, ileum, heart, and kidney tissues to determine malondialdehyde (MDA) and glutathione (GSH) levels and myeloperoxidase (MPO) activities. Data were analyzed by one-way analysis of variance and Tukey multiple comparison tests or Student's t test.

Results

Chronic nicotine administration or its withdrawal reduced lipid peroxidation and MPO activity and prevented GSH depletion with some varying results in different target tissues. Nicotine injection prior to sepsis depressed MPO activity in all tissues and reduced MDA levels except for the lung, while GSH levels were elevated only in the hepatic and ileal tissues. Histologically observed injury was ameliorated by all nicotine treatments at varying degrees.

Conclusions

The findings of the present study indicate that long-term nicotine administration reduces sepsis-induced oxidative damage in several tissues, which appears to involve inhibition of neutrophil activity in the inflamed tissues.

Implications

Nicotine administration or its withdrawal reduced lipid peroxidation and neutrophil content and prevented GSH depletion with some varying results in different target tissues. A single injection prior to sepsis induction depressed MPO activity in all the tissues and reduced all tissue MDA levels except for the lung. When nicotine was withdrawn for 5 days, its inhibitory effect on MPO activity was still present in all the tissues except for the liver. Microscopically an improved inflammatory response was observed in all the tissues of rats that have received different nicotine pretreatment regimens.

Ameliorative effect of chronic moderate exercise in smoke exposed or nicotine applied rats from acute stress

INTRODUCTION

Physical activity has been found to be related with many health benefits. Our aim was to investigate the effect of chronic moderate exercise from acute stress on nicotine and cigarette smoke exposed rats.

METHODS

Male Sprague Dawley rats (200-250g, n = 48) were divided into 6 groups as non-exercised, exercised, smoke exposed, smoke exposed and exercised, nicotine applied, and nicotine applied and exercised. Nicotine bitartarate was applied intraperitoneally (0.1mg/kg/day) for 5 weeks, and cigarette smoke was exposed in a ventilated chamber. After 1 week of nicotine application or smoke exposure, moderate exercise training protocol was applied to exercise groups. At the end of the experiments, acute stress induction was made to all groups by electric foot shock. Holeboard tests were performed before and after the experiments. Biochemical and histological analyses were performed in lung, liver, colon, stomach, and gastrocnemius tissues.

RESULTS

Malondialdehyde levels were increased in all tissues of smoke exposed group (p < .05-.01) except gastrocnemius tissue compared to non-exercised group and were decreased with exercise (p < .05-.001). Myeloperoxidase levels were increased in lung, liver and colon tissues of smoke exposed group (p < .05-.001) and liver and colon tissues of nicotine applied rats (p < .01-.001) and decrease with exercise in liver and colon tissues of both smoke exposed or nicotine applied groups (p < .05-.01). In all tissue samples, increased histological injury scores (p < .05-.001) decreased significantly with exercise (p < .01-.001).

CONCLUSION

Biochemical parameters and histological scoring indicated increased tissue injury due to nicotine application and cigarette smoke exposure and exercise training ameliorated these effects in most of the tissues of acute stress induced rats.