Background: The pancreas is a morphologically complex parenchymal organ composed of closely integrated exocrine and endocrine components responsible for digestive enzyme secretion and hormonal regulation of metabolism. Nicotine is a well-known toxic agent with cytotoxic, pro-oxidant, and vasoactive properties that can disrupt cellular homeostasis and induce structural damage in various organs, including the pancreas. Oxidative stress, apoptosis, and stromal remodeling are considered key mechanisms underlying nicotine-induced tissue injury. However, age-related morphofunctional changes in the pancreas under nicotine exposure remain insufficiently studied. Objective: To compare morphological and morphometric changes in the pancreas of 15-month-old rats under modeled nicotine intoxication with those of the control group. Materials and methods: The experimental study was conducted on 30 outbred white rats divided into two groups: control (n=15) and nicotine-exposed (n=15). Nicotine intoxication was modeled using passive tobacco smoke exposure in a 0.3 m³ glass chamber based on A.S. Solomin (2011) for 30 days, twice daily for 30 minutes. Histological examination of pancreatic tissue was performed using Hematoxylin-Eosin and Van Gieson staining. Morphometric analysis included assessment of exocrine and endocrine parenchymal areas, acinar dimensions, duct diameter, islet size, and cellular characteristics. Results: Nicotine exposure caused significant structural alterations in both exocrine and endocrine components of the pancreas. The relative area of exocrine parenchyma decreased, along with reductions in acinar diameter, epithelial height, and exocrinocyte size and number. The nucleus-to-cytoplasm ratio increased, indicating cellular stress and functional impairment. In the endocrine portion, reductions in islet number, size, endocrinocyte density, and cellular area were observed, reflecting decreased hormonal activity. Histological analysis revealed epithelial desquamation, nuclear swelling, chromatin dispersion, cytoplasmic shrinkage, connective tissue hypertrophy, and interstitial space formation. Van Gieson staining confirmed stromal fibrosis and tissue degeneration. Conclusion: One-month nicotine intoxication in 15-month-old rats induces pronounced morphological and morphometric alterations in the pancreas. These changes include suppression of exocrine and endocrine activity, structural disorganization, connective tissue remodeling, and cellular degeneration. The findings indicate that nicotine significantly impairs pancreatic structure and function through mechanisms associated with oxidative stress, apoptosis, and stromal fibrosis.

Nicotine intoxication, pancreas, morphology

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