Fig 2: The effect of HI and FAM3A expression on memory, spatial learning, and motor function. A cognitive function assessments were assessed when the animals were 6.5 weeks-old. NSS evaluation was based on 10-point system, with high scores indicative of more severe neurological impairments. NSS values for Ctrl-LV-Ctrl, HI-LV-Ctrl, and HI-LV-FAM3A are 0, 2.83, and 1.5, respectively. B and C grip test was performed at 6.5 weeks, both scores and grip time were recorded. Both overall grip score and amount of time spent holding onto the wire were significantly less in the HI group compared to the control group. HI-LV-FAM3A rats performed significantly better than the HI-LV-Ctrl rats on grip score and grip time. D the escape latency period in the Morris water maze test showed that rats in the HI group required more time to escape platform compared to the control group, and that HI-LV-FAM3A group required less time compared to the HI-LV-Ctrl group. n = 6 animals from each group, *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.001

Fig 3: HI inhibits FAM3A expression and contributes to increased mortality rate. A survival rate of pups born in the control were significantly higher than that of the HI group. B mRNA level of FAM3A in brain tissues show decreased FAM3A expression, lentivirus transduction showed increased FAM3A expression. C and D image and quantification of FAM3A protein expression. E and F image and quantification of immunofluorescence of FAM3A in CA1 using confocal microscope. n = 6 animals from each group 6 fields were taken for 3 slices per animal, *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.001

Fig 4: FAM3A expression contributes to improved neuronal cell morphology. A neuronal cell morphology in the cortex and hippocampus regions of the brain were examined through H&E staining. Neuronal cells in the HI group showed dark staining and small pyknotic nuclei, while control and FAM3A overexpressing groups demonstrated normal and round nuclei. Original magnification: ×400. B and C number of non-damaged neurons in the cortex and hippocampus. HI-LV-Ctrl group shows significantly less number of non-damaged cells compared to the Ctrl-LV-Ctrl and HI-LV-FAM3A groups. D % of cerebral water content. HI group demonstrated a 2.3% increase in cerebral water content, while FAM3A overexpression led to a 1.3% reduction. n = 6 animals from each group, *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.001