Early Angular Changes Of Keratocytes And Lamellar Pattern Of Collagen Fibers In Ocular Surface Injury Induced By Tobacco Smoke Exposure In Guinea Pig Corneas

Purpose: To evaluate early changes in keratocyte arrangement and lamellar pattern of collagen fibers in ocular surface injury induced by tobacco smoke exposure in guinea pig corneas.

Experimental Design: Sixteen male Hartley guinea pigs (250-300 g) were split into control (n=8, fresh air) and smoke-exposed (n=8) groups. The latter received smoke from 20 cigarettes/day (1 h/day) for 10 weeks via a SCIREQ Inexpose system. Procedures: At week 10, animals were tranquilized (xylazine 5-10 mg/kg) and anesthetized (ketamine 40-80 mg/kg) for CT biometry. 

Post-euthanasia (ketamine 300 mg/kg), eyes were enucleated and central corneas fixed in 4% paraformaldehyde. Paraffin sections (5 μm) were stained with H&E and Masson’s trichrome.  Data & Statistics: Using Image-J Fiji, we quantified collagen lamellar displacement, keratocyte length/angulation, and inflammatory infiltrate. Data (mean ± SEM) were analyzed via Student’s T-test (paired samples) in IBM SPSS v.31, with significance at P<0.05.

Results: Chronic qualitative changes were ruled out in each sample. Average length of displaced lamellae (μm): Control group: 6.786 + 0.354, p: 0.002, Exposed group: 33.167 +2.138,p: <0.001. Area of displacement between lamellae (μm²) Control group: 3.123 + 0.169, Exposed group 37.069 + 2.052, a minimum value of displacement to exposed group 153.226 + 3.125, p is <0.05. The angle of arrangement of the keratocytes with respect to the direction of lamellae: exposed group 81.259 °+1.053, control group: 9.255° + 2.115, p: <0.001.

Conclusión: Early changes in ocular surface from guinea pig eyes exposed to tobacco smoke are manifested as a change in the angle of the arrangement of keratocytes with respect to the direction of the lamellae that have suffered a significant area of displacement and a higher average length in the exposed group. identified early changes in keratocytes prior to these advanced stages could allow for earlier therapeutic interventions before corneal scar formation.