Cigarette Smoke Triggers Loss of Corneal Endothelial Cells and Disruption of Descemet's Membrane Proteins in Mice

Abstract

PURPOSE.To investigate changes at a molecular level in the mouse corneal endothelium (CE) exposed to chronic cigarette smoke (CS). METHODS.Pregnant mice (gestation days 18-20) were placed in a whole-body exposure smoking chamber, and a few days later pups were born. After 3.5 months of CS exposure, a ConfoScan4 scanning microscope was used to examine the corneal endothelial cells (CECs) of CS-exposed and control (Ct) mice. The CE was peeled under a microscope and maintained as four biological replicates (two male and two female) for CS-exposed and Ct mice; each replicate consisted of 16 CEs. The proteome of the CE was investigated through mass spectrometry. RESULTS.The CE images of CS-exposed and Ct mice revealed a difference in the shape of CECs accompanied by a nearly 10% decrease in CEC density (P < 0.00003) following CS exposure. Proteome profiling identified a total of 524 proteins exhibiting statistically significant changes in CE from CS-exposed mice. Importantly, proteins associated with Descemet's membrane (DM), including COL4α1, COL4α2, COL4α3, COL4α4, COL4α5, COL4α6, COL8α1, COL8α2, and FN1, among others, exhibited diminished protein levels in the CE of CS-exposed mice. CONCLUSIONS.Our data confirm that exposure to CS results in reduced CEC density accompanied by diminished levels of multiple collagen and extracellular matrix proteins associated with DM.

Effects of Type 2 Diabetes Mellitus and Smoking on Changes in Corneal Endothelial Morphology and Cell Density

“…Smoking is known to generate free radicals in the body, causing peripheral vasoconstriction and leading to decreased tissue oxygenation. [30][31][32] Chronic hyperglycemia leads to the accumulation of advanced glycation end products that promote inflammation and oxidative stress. Advanced glycation end products are believed to be responsible for the chronic macrovascular and microvascular complications of Descemet membrane.…”

“…Moreover, Zoega et al 29 found that smoking more than 20 pack-years (1 pack per day for 20 yrs) or half a pack per day for 40 years increased the odds ratio for corneal guttata by more than 2-fold. Recently, Ali et al 30 conducted a study on pregnant, adult, and newborn mice that were exposed to a smoking chamber, where they found that cigarette smoking influenced corneal endothelial cell.…”

Examining the effects of cigarette smoke on mouse lens through a multi OMIC approach

“…Exposure to CS in a whole-body smoke chamber. The mice were exposed to CS as described 27,28 . The smoke chamber contained a smoking machine (TE-10, Teague Enterprises, Davis, CA) that burns five cigarettes (2R4F reference cigarettes (2.45 mg nicotine/cigarette; Tobacco Research Institute, University of Kentucky) at a time, taking two-second duration puffs at a flow rate of 1.05 l/min, to provide a standard puff of 35 cm 3 , providing a total of eight puffs per minute.…”