A Study on Morphofunctional State of Djungarian Hamster (Phodopus Sungorus) Lungs and Main Organs of Detoxification under Long-Term Exposure to E-Cigarette Aerosol

Introduction. The liquids of electronic nicotine delivery systems (ENDS), which have the multi-component composition, represent a major environmental hazard, as they contain extremely toxic substances. Although the popularity of this form of smoking grows, the data on the biological effects of long-term exposure of animals and humans to e-cigarette and vape components are insufficient. The aim of the present study is to investigate the morphofunctional state of the lungs and main organs of detoxification in Djungarian hamsters under long-term exposure to ENDS aerosol.

Materials and Methods. The research was conducted in 2021 in the colony of laboratory Djungarian hamsters kept at the Institute of Systematics and Ecology of Animals SA RAS. Thirty-six hamsters were divided into two groups. During 80 days, animals in the experimental group (10 females and 10 males) were exposed to vapour from heating the X-3 Yoghurt Pear liquid. The procedure was performed twice a day for 10 minutes, with a 2-hour interval. Hamsters in the control group (8 males and 8 females) were placed in exposure chambers but were not exposed to vapour. At the end of the 80-day experiment, the animals were decapitated, and organs were collected for preparing thin histological sections. The specimens were stained with Boehmer’s hematoxylin and eosin. Collagen distribution was determined using the Mallory method. Histological specimens of organs were examined under transmission light microscope

Results. In experimental animals exposed to toxic vapour, a homogeneous black substance was detected in bronchial epithelial cells and in the alveolar interstitium. In the lung parenchyma, signs of developing interstitial pneumonia, atelectasis, emphysema, and obstructive bronchitis were detected, indicating impaired ventilation-perfusion relationships in the lung tissue and gas exchange disorder. In the kidneys, the homogeneous substance was localized in the lumen of renal tubules. Light optical microscopy revealed the main signs of lethal damage in renal epithelial cells. Strongly expressed dilation of the renal glomerular capillaries, coupled with a nearly 2-fold reduction in the surface area of renal corpuscles compared to control samples, indicates impaired hemodynamics and disrupted renal reabsorption-filtration function. Regarding the liver, a high level of localization of evolutionarily adapted to detoxification dark hepatocytes dying by apoptosis in the centrilobular region of the lobule, indicates the involvement of toxic substances in this process, which enter the liver with the blood.

Discussion and Conclusion. The experiment demonstrated the general pathogenic effects of ENDS aerosol on the lungs and organs of detoxification in animals after long-term exposure to it. Such studies are necessary in the context of the observed growth of consumption of the nicotine delivery systems at the global market. 

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