Horse Placental Extract Enhances Neurogenesis in the Presence of Amyloid β

Abstract

Human placental extract and animal-derived placental extracts from pigs and horses host a wide range of biological activities. Several placental products are used as medicines, cosmetics, and healthcare substances worldwide. However, the use of placental extracts for neuronal functioning is currently not established because the number of relevant studies is limited. A few previous reports suggested the neuroprotective effect and dendrite genesis effect of placental extract. However, no studies have reported on neurogenesis in placental extracts. Therefore, we aimed to investigate the effects of horse placental extract on neurogenesis, and we examined the protective effect of the extract on the onset of memory disorder. A horse placental extract, JBP-F-02, was used in this study. JBP-F-02 treatment dose-dependently increased the number of neural stem cells and dendrite length under Aβ treatment in primary cultured cortical cells. The oral administration of JBP-F-02 to a 5XFAD mouse model of Alzheimer's disease at a young age significantly prevented the onset of memory dysfunction. This study suggests that the extract has the potential to prevent dementia.

Keywords: Alzheimer’s disease; dendrite; horse placental extract; memory recovery; neurogenesis.

Figure 1

Effect of oral administration of JBP-F-02 on object recognition memory deficit in young 5XFAD mice. (A) JBP-F-02 mixed feed (0.03% and 3%) or a normal feed was administered for 58 days to mice (male and female, 13 weeks old). An object recognition test was carried out at day 43 with a 24 h interval between the training session and test session. The preferential indices of the training and test sessions are shown; * p < 0.05, two-tailed paired t-test. (B) Distance moved in an open field for 10 min; p > 0.05, one-way ANOVA. (C) Spent time as a percentage in peripheral zone of an open field. The peripheral zone was defined as a 5 cm wide area from the edge line; p > 0.05, one-way ANOVA. (D) Changes in body weights of mice during the experimental period; * p < 0.05, ** p < 0.01, *** p < 0.001 vs. normal feeding 5XFAD mice, repeated measures two-way ANOVA with post hoc Bonferroni’s test. (E) Oligomeric Aβ expression in the cerebral cortex; one-way ANOVA, post hoc Bonferroni’s test. (A–E) n = 4–6 mice. Means ± 95% CI. ANOVA, analysis of variance.

Figure 2

Effects of JBP-F-02 on Aβ-induced neuronal loss and dendrite atrophy. (A) Cortical neurons were cultured for 3 days and then treated with or without aggregated Aβ25–35 (10 μM). At the time of Aβ25–35 addition, the cells were simultaneously treated with JBP-F-02 at 0.02, 0.04, 0.2, 0.4, and 2 mg/mL concentration or a vehicle solution (distilled water). Four days after the treatment, the cells were fixed and immunostained for MAP2. Counter staining was done by DAPI. (B) MAP2-positive and DAPI-positive cells were counted as neurons. (C) MAP2-negative and DAPI-positive cells were counted as non-neurons. (D) The length of MAP2-positive dendrites. (E) Representative photos of the immunostained dendrites are shown; * p < 0.05, *** p < 0.001, **** p < 0.0001 vs. Aβ25–35-treated and vehicle solution-treated cells (black circle), one-way analysis of variance with post hoc Bonferroni’s test, n = 98 photos. Scale bar indicates 100 μm. Means ± 95% CI. Aβ, amyloid β; DAPI, 4’,6-diamidino-2-phenylindole dihydrochloride.

Figure 3

Effect of JBP-F-02 on neurogenesis under Aβ25–35 treatment. (A) Cortical neurons were cultured for 3 days and then treated with or without aggregated Aβ25–35 (10 μM). At the time of Aβ25–35 addition, the cells were simultaneously treated with JBP-F-02 at 0.2, 0.4, and 2 mg/mL concentration or a vehicle solution (distilled water). Six, 24, and 48 h after the treatment, the cells were fixed and immunostained for nestin and MAP2. (B) Nestin-positive and MAP2-positive cells were counted as neuronal stem cells. (C) Representative photos of the immunostained nestin are shown; *** p < 0.001, **** p < 0.0001 vs. Aβ25–35-treated and vehicle solution-treated dells (black columns), one-way analysis of variance with post hoc Bonferroni’s test, n = 32 photos. Scale bar indicates 100 μm. Means ± 95% CI. Aβ, amyloid β.

Figure 4

Effect of JBP-F-02 on neurogenesis under Aβ1–42 treatment. (A) Cortical neurons were cultured for 3 days and then treated with or without aggregated Aβ1–42 (1 μM). At the time of Aβ1–42 addition, the cells were simultaneously treated with JBP-F-02 at 0.2, 0.4, and 2 mg/mL concentration or a vehicle solution (distilled water). Four days after the treatment, the cells were fixed and immunostained for nestin and MAP2. (B) Nestin-positive and MAP2-positive cells were counted as neuronal stem cells; * p < 0.05, ** p < 0.01, *** p < 0.001 vs. Aβ1–42-treated and vehicle solution-treated cells (black circle), one-way analysis of variance with post hoc Bonferroni’s test, n = 32 photos. Means ± 95% CI. Aβ, amyloid β.