Effects of titanium dioxide nanoparticles on the myocardium of the adult albino rats and the protective role of β-carotene (histological, immunohistochemical and ultrastructural study).

Titanium dioxide nanoparticles (TiO NPs) are the most produced nanomaterials. TiO NPs are used as a drug carrier and molecular imaging vehicle in the cardiovascular system. We aimed to study TiO NPs effects on the ventricular myocardium and evaluate the ameliorative effects of β-carotene (βC). Forty adult albino rats were divided into four groups: negative control group (Ι) received a distilled water. Treated group (II): received 20 mg/kg/day TiONPs intraperitoneally. Protected group (III): received 10 mg/kg/day βC orally together with TiO NPs in a dose of 20 mg/kg/day intraperitoneally. Positive control group (IV) was given βC orally in a dose of 10 mg/kg/day for 14 days. Sections were stained with hematoxylin & eosin, bromphenol blue (BPB), and periodic acid Schiff (PAS). Anti-desmin & anti-CD45 immunohistochemical staining and electron microscopic examination were performed. Group (II) revealed fragmented myofibrils and inflammatory infiltrations. In group (III), normal cardiomyocytes with less inflammatory infiltrations. The optical density of PAS and BPB staining and anti-desmin showed a very highly significant decrease in the group (II) versus the control groups (P < 0.001). A highly significant increase in the optical density of group (III) versus group (II) (P < 0.01). Also, the area percentage mean values of collagen fibers and anti-CD45 in the group (II) showed a very highly significant increase versus the control groups (P < 0.001). Group (III) revealed a very highly significant decrease in the area percentage versus group (II) (P < 0.001). In conclusion: TiO NPs adversely affected the histological structure of the adult rat ventricular myocardium in acute exposure (14 days) and the damage was less with βC.