Thromboembolic injury and systemic toxicity induced by nicotine in mice

Nicotine is involved in the pathogenesis of hematological and cardiopulmonary diseases. The understanding of the pathophysiological mechanisms underlying these undesirable effects is however unclear. Cigarette smoking, nicotine gums and patches are common sources for nicotine ingestion. We have investigated the nicotine's effect on cerebral microvessel thrombosis and systemic toxicity. Mice received either nicotine (1 mg/kg, i.p.) or saline (control), once a day for 21 days. Briefly, after bolus intravenous fluorescein injection, a photo insult of cerebral microvessel was done. The platelet aggregation in microvessels was video recorded and analyzed. In conjunction, the plasma levels of superoxide dismutase (SOD), lactate dehydrogenase (LDH), liver enzymes, creatinine and blood urea nitrogen (BUN); and histopathological studies were carried out. Our results revealed a significant prothrombotic effect following nicotine exposure. Significant decrease in SOD indicates the occurrence of oxidative stress involved in the tissue damages and increase in the LDH emphasize the systemic toxicity. Substantial rise in the liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were observed. Lungs histology showed intra-vascular hemorrhagic infarction with necrosis, macrophage and neutrophils infiltration. Liver histology showed intravascular thrombosis and portal inflammation. We conclude that the sub-acute nicotine exposure causes an increase in thrombosis in cerebral microvessels and systemic, hepatic and pulmonary toxicity.