[Effects of nitric oxide synthase inhibitor on dentate gyrus neurogenesis after diffuse brain injury in adult rats].

Objective: To investigate the effects of selective nitric oxide synthase (NOS) inhibitors on dentate gyrus (DG) neurogenesis after diffuse brain injury (DBI) in adult rats.

Methods: DBI models were established in adult male SD rats, followed by systemic bromodeoxyuridine (BrdU) labeling of the dividing cells and immunohistochemical assay of the proliferation rates of neural precursor cells in the DG for comparison between NOS inhibitor (7-nitroindazole and Aminoguanidine) groups and the corresponding control groups at various time points after DBI.

Results: Intraperitoneal administration of 7-nitroindazole significantly reduced the number of BrdU-labeled cells in the DG of adult rats 2, 4 and 6 d after DBI (P<0.05). Aminoguanidine also significantly inhibited the proliferation of neural precursor cells in the DG induced by DBI at various time points (P<0.01).

Conclusions: The activation of NOS after DBI may be an important regulatory factor for DG neurogenesis in adult rats, and NO generated by nNOS is probably involved mainly in the early stage of enhanced neurogenesis after DBI, while the NO from iNOS might participated primarily in the later stages.