Evaluation of hazards of electronic -cigarette's liquid refill on testes of mice, complemented by histopathological and chromatographic analysis.

Abstract

Electronic-cigarettes (e-cigarettes) are devices designed to become an alternative to classic cigarettes. Vaping of e-cigarettes and their recharge liquid have become extremely popular among the adolescents; however, its safety is not well established. Evaluation of the components of e-cigarette liquid and their potential effects on testis of adult male mice. This aim will be fulfilled by histological, ultrastructural, and immunohistochemical analysis of mice testis biopsies. Twenty mice were allocated into two groups of equal size. The control group was given regular saline, whereas the treated group was given e-liquid (contains 3 mg of nicotine/kg of body weight) both groups daily intraperitoneally injected for 3 weeks. Analysis of e-liquid by Gas Chromatography-Mass Spectrometric GC/MS demonstrated nicotine, phenol, vanillin, aldehydes, and pyrethroid insecticide. Evaluation of oxidative stress parameters revealed significant reduction of SOD and GPx. Histological results revealed a significant reduction in the height of seminiferous tubules, sloughing of spermatogenic cells, most cells being dark and pyknotic, and thickening of the interstitium with accumulation of PAS positive exudate. Most spermatogenic cells showed degenerative changes as rarefied cytoplasm, ill-defined electron-dense nuclei, and elongated spermatid showed deformity of ectoplasmic specialization. Immunohistochemical studies revealed a significant increase in caspase-3 positive cells and a significant reduction of area % of E-cadherin. The analysis of an available E-liquid demonstrated potentially harmful chemicals that are not shown in the labeling of the product. E-liquid appears to impair anti-oxidant defense and cause degenerative changes in the body and disruption of blood testes barrier BTB. So, e-cigarettes cannot be regarded as a non-harmful smoking replacement.