Objective: The effects of loud noise (80 dB) on neurogenesis in the sub-ventricular zone (SVZ) and the
hippocampal sub-granular zone (SGZ) was investigated in vivo in the rat brain using positron emission tomography
(PET) with 3’-deoxy-3’- [18F]fluoro-L-thymidine ( [18F]FLT), a marker for thymidine kinase I (TK-1) related to cell
proliferation and for neurogenesis in SVZ and SGZ.
Methods: Five young Sprague-Dawley rats were exposed to loud noise from two speakers set in front of their
cages during the night for 4 nights, and 5 control rats were exposed to normal quiet conditions. PET was performed
4 days after the exposure.
Results: The accumulation of [18F] FLT in SVZ was significantly lower in the rats with noise exposure than in the
control rats. The level of [18F] FLT uptake was lower in the SVZ than in the SGZ.
Conclusion: Our results indicate that loud noise exposure during the awake period may be related to the
decrease in proliferative capacity of neural stem cells especially in the SVZ of the living rat brain. This finding may
indicate that persistent loud noise during daily life is harmful to brain development in humans.