1：Experimental Design and Method Selection:

The cognitive function of rats was evaluated by the Morris water maze (MWM) test and the novel object recognition test. The content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the hippocampus were detected by enzyme-linked immunosorbent assay (ELISA). The neuronal apoptosis in the hippocampal CA1 region was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end (TUNEL) staining. The expression of the BDNF protein was detected by Western blot and immunohistochemistry.

2：Sample Selection and Data Sources:

Adult male Sprague-Dawley rats (250–280 g) were obtained from the Laboratory Animal Center of University of South China.

3：List of Experimental Equipment and Materials:

FA and sodium hydrosulfide (NaHS) were obtained from Sigma-Aldrich. In situ apoptosis detection kit (POD) was supplied by Roche Diagnostics. Malondialdehyde (MDA) enzyme-linked immunosorbent assay (ELISA) kit was purchased from Uscn Life Science Inc. Total superoxide dismutase (SOD) assay kit was purchased from Beyotime Biological Co., Ltd. Specific monoclonal antibody to BDNF was obtained from Epitomic Inc.

4：Experimental Procedures and Operational Workflow:

Rats were pretreated with NaHS (10, 30, or 100 μmol/kg/day, i.p.) for 7 days and co-treated with FA (10 μmol/day, i.c.v.) for 7 days. Behavioral tests were performed 24 h after the last injection. The second day after the end of the behavioral tests, the animals were killed, and the hippocampus region tissues of the brain were rapidly removed and stored at –80 °C until analysis.

5：Data Analysis Methods:

Data are expressed as mean ± SEM. The significance of intergroup differences was evaluated by one-way analyses of variance (ANOVA: least-significant difference test). Statistical significance was considered at p < 0.05.