Indole‐3‐propionic acid attenuates neuronal damage and oxidative stress in the ischemic hippocampus

Abstract

Tryptophan-derived indole compounds have been widely investigated as antioxidants and as free-radical scavengers. Indole-3-propionic acid (IPA), one of these compounds, is a deamination product of tryptophan. In the present study, we used Mongolian gerbils to investigate IPA's neuroprotective effects against ischemic damage and its antioxidative effects in the hippocampal CA1 region (CA1) after 5 min of transient forebrain ischemia. The repeated oral administration of IPA (10 mg/kg) for 15 days before ischemic surgery protected neurons from ischemic damage. In this group, the percentage of cresyl violet-positive neurons in the CA1 was 56.8% compared with that in the sham group. In the vehicle-treated group, glial fibrillary acidic protein (GFAP)-, S-100-, and vimentin-immunoreactive astrocytes and ionized calcium-binding adapter molecule 1 (Iba-1)- and isolectin B4 (IB4)-immunoreactive microglia were activated 4 days after ischemia/reperfusion, whereas in the IPA-treated ischemic group, GFAP, S-100, Iba-1, and IB4, but not vimentin, immunoreactivity was distinctly lower than that in the vehicle-treated ischemic groups. The administration of IPA significantly decreased the level of 4-hydroxy-2-nonenal, a marker of lipid peroxidation, in ischemic hippocampal homogenates compared with that in the vehicle-treated ischemic groups at various times after ischemia/reperfusion. In addition, immunostaining for 8-hydroxy-2'-deoxyguanosine showed DNA damage in pyramidal neurons in the ischemic CA1 was significantly lower in the IPA-treated ischemic groups than in the vehicle-treated ischemic groups. These results suggest that IPA protects neurons from ischemia-induced neuronal damage by reducing DNA damage and lipid peroxidation.

Bacterial Neuroactive Compounds Produced by Psychobiotics

“…IPA has been shown to be a powerful antioxidant [71] and has been considered as a possible treatment for Alzheimer's disease [72] due to its ability to protect neurons and neuroblastoma cells against oxidative damage and death [73,74].…”

Time Course of Postnatal Distribution of Doublecortin Immunoreactive Developing/Maturing Neurons in the Somatosensory Cortex and Hippocampal CA1 Region of C57BL/6 Mice

“…Thereafter, paraffin-embedded tissues were coronally sectioned on a microtome (Leica, Wetzlar, Germany) into 3-lm thickness containing the SSC or hippocampus, and they were mounted onto saline-coated slides. The sections were stained with cresyl violet acetate according to a previously described procedure (Hwang et al 2009). …”

“…The hippocampus, a part of limbic system in the brain, is involved in memory formation and affective state. In addition, this region is associated with some brain diseases such as seizure, ischemia, and Alzheimer's disease (Hwang et al 2009;Liu et al 2009). Recently, this region has received additional attention because neurogenesis occurs in the hippocampal dentate gyrus throughout life (Eriksson et al 1998;Gage et al 1998;McDonald and Wojtowicz 2005).…”

Relation Among Neuronal Death, Cell Proliferation and Neuronal Differentiation in the Gerbil Main Olfactory Bulb after Transient Cerebral Ischemia

“…In this study, we observed, like other researches that significant neuronal loss occurred in the gerbil hippocampal CA1 region after 5 min of transient cerebral ischemia (Kirino and Sano 1984;Hwang et al 2009). We previously reported that NeuN-immunoreactive neurons were significantly decreased in the gerbil GL induced by transient cerebral ischemia (Hwang et al 2004).…”

“…Restoration of blood flow (reperfusion) was observed directly under the ophthalmoscope. The body (rectal) temperature under free-regulating or normothermic (37 ± 0.5°C) conditions was maintained with a rectal temperature probe (TR-100; YSI, USA) and thermometric blanket before, during and after the surgery until the animals fully recovered from anesthesia (Hwang et al 2009). Thereafter, animals were kept on thermal incubator (Mirae Medical Industry, South Korea) to maintain the body temperature of animals until the animals were killed.…”