ABSTRACT
<p><b>AIM</b>To study the expression and effect of TLR4 and NFkappaB protein in hippocampus neuron in rats exposed to chronic hypoxic hypercapnia.</p><p><b>METHODS</b>The disorder of learning-memory in pulmonary hypertension rat model was reproduced by chronic hypoxic hypercapnia. Thirty rats were randomly divided into three groups: normal control group, hypoxic hypercapnia 2-week and 4-week group. The number of apoptosis neurons in hippocampus CA1/3 was counted by TUNEL method. Activity of TLR4 and NFkappaB in hippocampus CA1/3 was detected by using SP immunocytochemical technique.</p><p><b>RESULTS</b>The expression of TLR4 protein in hippocampus CA1/3 in group 2HH( CA1: 0.1275 +/- 0.0242, CA3: 0.1156 +/- 0.0376) and 4HH (CA1: 0.1522 +/- 0.0187, CA3: 0.1427 +/- 0.0453) were significantly higher than those in the NC group (P < 0.05, P < 0.01). The positive expression of NFkappaB were showed in cell nucleus in group 2HH (CA1: 0.1326 +/- 0.0324, CA3: 0.1301 +/- 0.0112) and group 4HH (CA1: 0.1612 +/- 0.0428, CA3: 0.1578 +/- 0.0365), and significantly higher than those in the NC group (P < 0.05, P < 0.01). The apoptosis of neural cells in hippocampus CA1/3 gradually increased with the time of exposure, and reached peak at 4 weeks (P < 0.01 vs NC group).</p><p><b>CONCLUSION</b>The activation of TLR4 and NFkappaB may play an important role in the apoptosis of hippocampus neural cells in rat exposed to chronic hypoxic hypercapnia.</p>