The expression of inducible nitric oxide synthase and endothelial nitric oxide synthase in the heart of smoking rats: An immunohistochemical study.

Background: Smoking is a severe health problem because it impacts the health of individuals through direct impacts on the cardiovascular system. Study Objective: The present study aimed to investigate the expression of nitric oxide synthase isoforms in the heart of smoking rats. Methodology: A total of 20 albino male rats were randomly assigned into two groups, the control group (N=10) and the smoking group (N=10). Smoking group rats were exposed to smoking using the smoking box for one month. Control group rats were exposed to fresh air. At the end of the experiment, all animals were terminated using ether. The heart tissues of all animals were taken and fixed in 10% formalin. Heart tissues were further processed and stained for nitric oxide synthase isoforms, Inducible Nitric Oxide Synthase (iNOS), Endothelial Nitric Oxide Synthase (eNOS), and Neuronal Nitric Oxide Synthase (nNOS) using immunohistochemistry (Indirect immunoperoxidase enyme). The expression of NOS isoforms was calculated using Adobe Photoshop version 7.2. Antibody-stained section micrographs were analyzed using pixels. The pixels revealed the presence of the biomarker (brown) and residual tissue (blue). The relationships between the groups were computed by independent T-test. Significance was considered if p-value 0.05. Results: The results showed that the expression of iNOS was significantly upregulated in the smoking group compared with the control group (p=0.003). The expression of eNOS was significantly downregulated in the smoking group compared with the control group (p=0.01). The expression of nNOS was not significantly varied among study groups (p=0.058). Conclusion: This study showed that smoking negative impacts of smoking on the heart are mediated by variations in the expression of NOS isoforms, a matter that bears potential therapeutic strategies to overcome smoking outcomes. [ABSTRACT FROM AUTHOR]