Abstract： Objective To investigate the relation between noggin expression changes and granular cell proliferation in the dentate gyrus subgranular zone (DG-SGZ) in rats with kainic acid (KA)-induced hippocampal injury. Methods Thirty-two adult male SD rats were randomly assigned into KA injury group (n=16) for intracerebroventricular KA injection and control group (n=16) which received intracerebroventricular normal saline injection (n=8) or no treatment (n=8). Nissl staining was used to assess the cell loss in the hippocampus, and in situ hybridization and immunofluorescence staining was used to detect noggin expression and BrdU-labeled cells in the DG-SGZ. Results The BrdU-labeled cells were found mainly in the DG-SGZ, and noggin mRNA-positive cells mainly in the hilus, DG-SGZ, CA3 and CAI area of the hippocampus. Seven days after KA treatment, substantial cell loss was found in the CA3 and CA4 areas, and the number of BrdU-labeled cells in the DG-SGZ markedly increased as compared with that in the saline group, especially on the same side of injection (P=0.006). The number of noggin mRNA-positive cells in the hippocampus significantly increased 3 days after KA injection, and began to decrease on day 7. Conclusion The granular cell proliferation in the DG-SGZ after KA-induced rat hippoeampal injury is probably associated with noggin expression changes in the hippoeampus.