The effect of selective neuronal nitric oxide synthase inhibitor on apoptosis of neurons after hypoxic-ischemic brain damage in neonatal rats

Apoptosis which is one of the main patterns of neuronal death plays an important role in the delayed brain damage after hypoxic-ischemic brain damage (HIBD). We have studied the effect of 7-nitroindazole (7-NI)-selective neuronal NOS (nNOS) inhibitor on apoptosis of neurons after HIBD. The HIBD model was produced in the 7-day postnatal SD rats which were subjected to permanent unilateral carotid artery ligation followed by an hypoxic (8% oxygen) insult of 2 hours. 7-Ni and PBS were administered after HIBD respectively. Neuronal apoptosis was examined using HE-staining, TUNEL staining and electron microscopy 24 hours later. Morphological characteristic changes of apoptosis in different stages were revealed. The number of neuronal apoptosis in hippocampus and cortex in the 7-NI group at 24h after HIBD was significantly lower than that in the PBS group (p<0.005). This study demonstrated that apoptosis play important role in the delayed neuronal death after HIBD, and first proved it is selective NOS inhibitors (7-NI) that shows its anti-apoptosis effect on HIBD.