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Soyasaponin I improved neuroprotection and regeneration in memory deficient model rats.

Hong SW, Heo H, Yang JH, Han M, Kim DH, Kwon YK - PLoS ONE (2013)

Bottom Line: Oral administration of soya-I exhibited significant memory-enhancing effects in the passive avoidance, Y-maze, and Morris water maze tests.Addition of soya-Ι in the cultured NPCs significantly elevated the markers for cell proliferation (Ki-67) and neuronal differentiation (NeuN, TUJ1, and MAP2).Soya-Ι may improve hippocampal learning and memory impairment by promoting proliferation and differentiation of NPCs in the hippocampus through facilitation of neuronal regeneration and minimization of neuro-inflammation.

View Article: PubMed Central - PubMed

Affiliation: Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Hoegi-dong, Dongdaemoon-gu, Seoul, Republic of Korea.

ABSTRACT
Soy (Glycine Max Merr, family Leguminosae) has been reported to possess anti-cancer, anti-lipidemic, estrogen-like, and memory-enhancing effects. We investigated the memory-enhancing effects and the underlying mechanisms of soyasaponin I (soya-I), a major constituent of soy. Impaired learning and memory were induced by injecting ibotenic acid into the entorhinal cortex of adult rat brains. The effects of soya-I were evaluated by measuring behavioral tasks and neuronal regeneration of memory-deficient rats. Oral administration of soya-I exhibited significant memory-enhancing effects in the passive avoidance, Y-maze, and Morris water maze tests. Soya-Ι also increased BrdU incorporation into the dentate gyrus and the number of cell types (GAD67, ChAT, and VGluT1) in the hippocampal region of memory-deficient rats, whereas the number of reactive microglia (OX42) decreased. The mechanism underlying memory improvement was assessed by detecting the differentiation and proliferation of neural precursor cells (NPCs) prepared from the embryonic hippocampus (E16) of timed-pregnant Sprague-Dawley rats using immunocytochemical staining and immunoblotting analysis. Addition of soya-Ι in the cultured NPCs significantly elevated the markers for cell proliferation (Ki-67) and neuronal differentiation (NeuN, TUJ1, and MAP2). Finally, soya-I increased neurite lengthening and the number of neurites during the differentiation of NPCs. Soya-Ι may improve hippocampal learning and memory impairment by promoting proliferation and differentiation of NPCs in the hippocampus through facilitation of neuronal regeneration and minimization of neuro-inflammation.

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Effects of soya-Ι on behavioral tests 4 weeks after soya-I administration in memory-deficient rats.A. A time line of experimental procedures B. Behavioral effect of soya-I on memory-deficient model rats 4 weeks after oral administration. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and passive avoidance tests (B) and Y-maze tests (C) were carried out 3 weeks later. The sham group was injected with saline instead of IBO. B. Latency times in passive avoidance test and C. spontaneous alterations in the Y-maze test during 8-min sessions were measured as described in Materials and Methods. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and the Morris water maze task was carried out 3 weeks later. The sham group was injected with saline instead of IBO. D. Total entries were not significantly different. E. The mean escape latency to find the hidden platform during 4 consecutive days of training trials, F. the number of virtual platform crossings and G. swimming time in the target quadrant in 60-s probe trials with no platform were measured as described in Materials and Methods. Closed square = Sham group, opened triangle = IBO group, open circle = soya-I treated group. Data represent means ± SEM (#p < 0.05, ##p < 0.01, ###p < 0.001, compared with the sham group, *p < 0.05, **p < 0.01, ***p < 0.001, compared with the IBO group by the Newman-Keuls Multiple Comparison Test).
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pone-0081556-g004: Effects of soya-Ι on behavioral tests 4 weeks after soya-I administration in memory-deficient rats.A. A time line of experimental procedures B. Behavioral effect of soya-I on memory-deficient model rats 4 weeks after oral administration. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and passive avoidance tests (B) and Y-maze tests (C) were carried out 3 weeks later. The sham group was injected with saline instead of IBO. B. Latency times in passive avoidance test and C. spontaneous alterations in the Y-maze test during 8-min sessions were measured as described in Materials and Methods. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and the Morris water maze task was carried out 3 weeks later. The sham group was injected with saline instead of IBO. D. Total entries were not significantly different. E. The mean escape latency to find the hidden platform during 4 consecutive days of training trials, F. the number of virtual platform crossings and G. swimming time in the target quadrant in 60-s probe trials with no platform were measured as described in Materials and Methods. Closed square = Sham group, opened triangle = IBO group, open circle = soya-I treated group. Data represent means ± SEM (#p < 0.05, ##p < 0.01, ###p < 0.001, compared with the sham group, *p < 0.05, **p < 0.01, ***p < 0.001, compared with the IBO group by the Newman-Keuls Multiple Comparison Test).

Mentions: If newly born NPCs survive and get incorporated into the neural network in addition to neuronal cell types increased at 1 week, abilities of memory formation could be maintained. We investigated whether the effect of soya-I on memory recovery at 1 week after the administration could be maintained over 4 weeks by conducting the Y-maze, passive avoidance, Morris water maze tests. The behavioral tests were performed 4 weeks after oral administration of soya-Ι at 10 mg·kg-1 once daily for 1 week (Figure 4A), because memory recovery was best at 10 mg·kg-1 soya-I (Figure 1B). In the passive avoidance test, the latency time of the soya-Ι-treated group was recovered dramatically compared with IBO group and to 89.65 % of that of the sham group (### p < 0.001 by Newman-Keuls Multiple Comparison Test, IBO group were compared with Sham group, *** p < 0.001 by Newman-Keuls Multiple Comparison Test, Soya-I 10 mg·kg-1 group were compared with IBO group; F2,27 = 40.57, p < 0.0001 by One-way ANOVA; Figure 4B). In the Y-maze test, spontaneous alterations in the soya-Ι-treated group showed a significant increase, by 78.57 %, compared with the IBO group (### p < 0.001 by Newman-Keuls Multiple Comparison Test, IBO group were compared with Sham group, ** p < 0.01 by Newman-Keuls Multiple Comparison Test, Soya-I 10 mg·kg-1 group were compared with IBO group; F2,27 = 25.57, p < 0.0001 by One-way ANOVA; Figure 4C), whereas the numbers of total entries were not significantly different among all groups (Figure 4D). In the training trial session of the Morris water maze test, the escape latency time for finding the hidden platform in the sham and soya-Ι groups declined progressively during the training period of 4 consecutive days in comparison with the IBO group. In particular, on the third and fourth days, the escape latency time in the soya-Ι-treated group was reduced than that of the IBO group (Day 3, F2,29 = 14.29, p < 0.0001; Day 4, F2,29 = 9.985, p = 0.0004; Figure 4E). In the probe trial session, the number of crossings across the target probe and swimming times within the target quadrant in the soya-Ι-treated group showed reduced tendency in the IBO group and recovered almost that of the sham group (Swimming time, F2,29 = 21.07, p < 0.0001; target crossing, F2,29 = 25.63, p < 0.0001; Figure 4F, G). These results indicate that the memory improvements in behavioral tests resulting from soya-I administration lasted for 4 weeks after the administration.


Soyasaponin I improved neuroprotection and regeneration in memory deficient model rats.

Hong SW, Heo H, Yang JH, Han M, Kim DH, Kwon YK - PLoS ONE (2013)

Effects of soya-Ι on behavioral tests 4 weeks after soya-I administration in memory-deficient rats.A. A time line of experimental procedures B. Behavioral effect of soya-I on memory-deficient model rats 4 weeks after oral administration. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and passive avoidance tests (B) and Y-maze tests (C) were carried out 3 weeks later. The sham group was injected with saline instead of IBO. B. Latency times in passive avoidance test and C. spontaneous alterations in the Y-maze test during 8-min sessions were measured as described in Materials and Methods. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and the Morris water maze task was carried out 3 weeks later. The sham group was injected with saline instead of IBO. D. Total entries were not significantly different. E. The mean escape latency to find the hidden platform during 4 consecutive days of training trials, F. the number of virtual platform crossings and G. swimming time in the target quadrant in 60-s probe trials with no platform were measured as described in Materials and Methods. Closed square = Sham group, opened triangle = IBO group, open circle = soya-I treated group. Data represent means ± SEM (#p < 0.05, ##p < 0.01, ###p < 0.001, compared with the sham group, *p < 0.05, **p < 0.01, ***p < 0.001, compared with the IBO group by the Newman-Keuls Multiple Comparison Test).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3852400&req=5

pone-0081556-g004: Effects of soya-Ι on behavioral tests 4 weeks after soya-I administration in memory-deficient rats.A. A time line of experimental procedures B. Behavioral effect of soya-I on memory-deficient model rats 4 weeks after oral administration. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and passive avoidance tests (B) and Y-maze tests (C) were carried out 3 weeks later. The sham group was injected with saline instead of IBO. B. Latency times in passive avoidance test and C. spontaneous alterations in the Y-maze test during 8-min sessions were measured as described in Materials and Methods. Rats were orally administered soya-Ι (10 mg·kg-1, p.o.) or vehicle (same volume, p.o.) once per day for 7 days, and the Morris water maze task was carried out 3 weeks later. The sham group was injected with saline instead of IBO. D. Total entries were not significantly different. E. The mean escape latency to find the hidden platform during 4 consecutive days of training trials, F. the number of virtual platform crossings and G. swimming time in the target quadrant in 60-s probe trials with no platform were measured as described in Materials and Methods. Closed square = Sham group, opened triangle = IBO group, open circle = soya-I treated group. Data represent means ± SEM (#p < 0.05, ##p < 0.01, ###p < 0.001, compared with the sham group, *p < 0.05, **p < 0.01, ***p < 0.001, compared with the IBO group by the Newman-Keuls Multiple Comparison Test).
Mentions: If newly born NPCs survive and get incorporated into the neural network in addition to neuronal cell types increased at 1 week, abilities of memory formation could be maintained. We investigated whether the effect of soya-I on memory recovery at 1 week after the administration could be maintained over 4 weeks by conducting the Y-maze, passive avoidance, Morris water maze tests. The behavioral tests were performed 4 weeks after oral administration of soya-Ι at 10 mg·kg-1 once daily for 1 week (Figure 4A), because memory recovery was best at 10 mg·kg-1 soya-I (Figure 1B). In the passive avoidance test, the latency time of the soya-Ι-treated group was recovered dramatically compared with IBO group and to 89.65 % of that of the sham group (### p < 0.001 by Newman-Keuls Multiple Comparison Test, IBO group were compared with Sham group, *** p < 0.001 by Newman-Keuls Multiple Comparison Test, Soya-I 10 mg·kg-1 group were compared with IBO group; F2,27 = 40.57, p < 0.0001 by One-way ANOVA; Figure 4B). In the Y-maze test, spontaneous alterations in the soya-Ι-treated group showed a significant increase, by 78.57 %, compared with the IBO group (### p < 0.001 by Newman-Keuls Multiple Comparison Test, IBO group were compared with Sham group, ** p < 0.01 by Newman-Keuls Multiple Comparison Test, Soya-I 10 mg·kg-1 group were compared with IBO group; F2,27 = 25.57, p < 0.0001 by One-way ANOVA; Figure 4C), whereas the numbers of total entries were not significantly different among all groups (Figure 4D). In the training trial session of the Morris water maze test, the escape latency time for finding the hidden platform in the sham and soya-Ι groups declined progressively during the training period of 4 consecutive days in comparison with the IBO group. In particular, on the third and fourth days, the escape latency time in the soya-Ι-treated group was reduced than that of the IBO group (Day 3, F2,29 = 14.29, p < 0.0001; Day 4, F2,29 = 9.985, p = 0.0004; Figure 4E). In the probe trial session, the number of crossings across the target probe and swimming times within the target quadrant in the soya-Ι-treated group showed reduced tendency in the IBO group and recovered almost that of the sham group (Swimming time, F2,29 = 21.07, p < 0.0001; target crossing, F2,29 = 25.63, p < 0.0001; Figure 4F, G). These results indicate that the memory improvements in behavioral tests resulting from soya-I administration lasted for 4 weeks after the administration.

Bottom Line: Oral administration of soya-I exhibited significant memory-enhancing effects in the passive avoidance, Y-maze, and Morris water maze tests.Addition of soya-Ι in the cultured NPCs significantly elevated the markers for cell proliferation (Ki-67) and neuronal differentiation (NeuN, TUJ1, and MAP2).Soya-Ι may improve hippocampal learning and memory impairment by promoting proliferation and differentiation of NPCs in the hippocampus through facilitation of neuronal regeneration and minimization of neuro-inflammation.

View Article: PubMed Central - PubMed

Affiliation: Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Hoegi-dong, Dongdaemoon-gu, Seoul, Republic of Korea.

ABSTRACT
Soy (Glycine Max Merr, family Leguminosae) has been reported to possess anti-cancer, anti-lipidemic, estrogen-like, and memory-enhancing effects. We investigated the memory-enhancing effects and the underlying mechanisms of soyasaponin I (soya-I), a major constituent of soy. Impaired learning and memory were induced by injecting ibotenic acid into the entorhinal cortex of adult rat brains. The effects of soya-I were evaluated by measuring behavioral tasks and neuronal regeneration of memory-deficient rats. Oral administration of soya-I exhibited significant memory-enhancing effects in the passive avoidance, Y-maze, and Morris water maze tests. Soya-Ι also increased BrdU incorporation into the dentate gyrus and the number of cell types (GAD67, ChAT, and VGluT1) in the hippocampal region of memory-deficient rats, whereas the number of reactive microglia (OX42) decreased. The mechanism underlying memory improvement was assessed by detecting the differentiation and proliferation of neural precursor cells (NPCs) prepared from the embryonic hippocampus (E16) of timed-pregnant Sprague-Dawley rats using immunocytochemical staining and immunoblotting analysis. Addition of soya-Ι in the cultured NPCs significantly elevated the markers for cell proliferation (Ki-67) and neuronal differentiation (NeuN, TUJ1, and MAP2). Finally, soya-I increased neurite lengthening and the number of neurites during the differentiation of NPCs. Soya-Ι may improve hippocampal learning and memory impairment by promoting proliferation and differentiation of NPCs in the hippocampus through facilitation of neuronal regeneration and minimization of neuro-inflammation.

Show MeSH
Related in: MedlinePlus