Effect of Intranasally Administered Stem Cell-Derived Exosomes on Rat's Olfactory Bulb Histological Structure After Lead-Oxide Nanoparticle Administration.

Lead is a common heavy metal used in a variety of products. We investigated the effect of lead-oxide nanoparticles (PbO-NPs) on the histological structure of the rat olfactory bulb (OB) and the potential therapeutic effect of stem cell-derived exosomes (EXOs). Forty male rats were included: 8 for EXO isolation and 32 were distributed into 4 groups: control, PbO-NPs group [intranasal (IN) 50 µL PbO-NPs/rat for 3 weeks], recovery group (PbO-NPs for 3 weeks and left for another 4 weeks), and PbO-NP-EXO (PbO-NPs for 3 weeks then IN EXO for another 3 weeks).