There have been concerns about the potential health risks posed by microplastics (MP).
The detection of MP in a variety of food products revealed that humans are ingesting MP. Nevertheless,
there is a paucity of data about their impacts, as well as their uptake, on intestinal barrier
integrity. This study examined the toxic effects of oral administration of two doses of polyethylene
microplastics (PE-MP) (3.75 or 15 mg/kg/day for 5 weeks; mean particle size: 4.0–6.0 m) on the
intestinal barrier integrity in rats. Moreover, the effect of melatonin treatment with MP exposure
was also assessed. The PE-MP particle uptake, histopathological changes, Alcian blue staining,
Muc2 mRNA, proinflammatory cytokines (IL-1 and TNF- ), and cleaved caspase-3, as well as tight
junction proteins (claudin-1, myosin light-chain kinase (MLCK), occludin, and zonula occludens-1
(ZO-1)) were assessed. Oral administration of PE-MP resulted in apparent jejunal histopathological
alterations; significantly decreased mucin secretion, occludin, ZO-1, and claudin-1 expression; and
significantly upregulated MLCK mRNA, IL-1 concentration, and cleaved caspase-3 expression.
Melatonin reversed these altered parameters and improved the PE-MP-induced histopathological
and ultrastructure changes. This study highlighted the PE-MP’s toxic effect on intestinal barrier
integrity and revealed the protective effect of melatonin. |
