Incense smoke is reported to increase cardiovascular disease (CVD) risk in exposed individuals. However, the mechanism underlying the toxic effect of incense smoke on cardiovascular system is unclear. To test this, we chronically exposed male albino rats to two different types of Arabian incense smoke and studied their effects on oxidative stress, inflammation, and endothelial function. Rats exposed to either of incense smoke showed a significant increase in malondialdehyde (MDA) and a significant decline in superoxide dismutase (SOD) and reduced glutathione (GSH). Endothelial functional marker, nitric oxide (NO) was significantly decreased while endothelin-1 was significantly increased in rats exposed to both the incense types. Incense smoke exposure also led to a significant increase in chemokines and inflammatory mediators including monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage-colony stimulating factor (GM-CSF), regulated on activation normal T cell expressed and secreted (RANTES), interleukin-4 (IL-4), C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-α). Besides, incense smoke-exposed rats demonstrated a significant increase in the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecules-1 (VCAM-1), and E-selectin. Importantly, cessation of incense smoke exposure for 30 days led to a significant reversal in the levels of all the studied markers. Collectively, this study describes oxidative stress, endothelial dysfunction, and inflammation as possible underlying mechanisms in the toxic effects of incense smoke on increased CVD risk in exposed individuals. Findings also underscore that avoiding incense smoke exposure may have beneficial health effects.
Keywords: Incense; adhesion molecules; chemokines; endothelial dysfunction; inflammation; oxidative stress.