Manzhong Li1, Junyao Ouyang1, Yi Zhang2, Brian Chi Yan Cheng3, Yu Zhan1, Le Yang1, Haiyan Zou4, Hui Zhao5. 1. School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing 100069, China. 2. Department of pharmacology, Beijing University of Chinese Medicine, Beijing 100102, China. 3. College of Professional and Continuing Education, The Hong Kong Polytechnic University, Hung Hom, Hong Kong. 4. School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing 100069, China. Electronic address: bwzhy@sina.com. 5. School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Lab of TCM Collateral Disease Theory Research, Beijing 100069, China. Electronic address: zhaohuishouyi@sina.com.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Trillium tschonoskii rhizome (TTR), a medicinal herb, has been traditionally used to treat traumatic brain injury and headache in China. Although the potential neuroprotective efficacy of TTR has gained increasing interest, the pharmacological mechanism remains unclear. Steroid saponins are the main bioactive components of the herb. AIM OF THE STUDY: To investigate the protective and repair-promoting effects of the total saponins from TTR (TSTT) on grey and white matter damages in a rat model of middle cerebral artery occlusion (MCAO) using magnetic resonance imaging (MRI) assay. MATERIALS AND METHODS: Ischemic stroke was induced by MCAO. TSTT and Ginaton (positive control) were administered orally to rats 6h after stroke and daily thereafter. After 15 days of treatment, the survival rate of each group was calculated. We then conducted neurological deficit scores and beam walking test to access the neurological function after ischemic stroke. Subsequently, T2-weighted imaging (T2WI) and T2 relaxometry mapping were performed to measure infarct volume and grey and white matter integrity, respectively. Moreover, diffusion tensor imaging (DTI) was carried out to evaluate the grey and white matter microstructural damage. Additionally, arterial spin labelling (ASL) - cerebral blood flow (CBF) and magnetic resonance angiography (MRA) images provided dynamic information about vascular hemodynamic dysfunction after ischemic stroke. Finally, haematoxylin and eosin (HE) staining was carried out to evaluate the stroke-induced pathological changes in the brain. RESULTS: The survival rate and neurological behavioural outcomes (Bederson scores and beam walking tests) were markedly ameliorated by TSTT (65mg/kg) treatment within 15 days after ischemic stroke. Moreover, T2WI and T2 relaxometry mapping showed that TSTT (65mg/kg) significantly reduced infarct volume and attenuated grey and white matter injury, respectively, which was confirmed by histopathological evaluation of brain tissue. The results obtained from DTI showed that TSTT (65mg/kg) not only significantly alleviated axonal damage and demyelination, but also promoted axonal remodelling and re-myelination. In addition, TSTT treatment also enhanced vascular signal density and increased CBF in rats after MCAO. CONCLUSION: Our results suggested the potential protective and repair-promoting effects of TSTT on grey and white matter from damage induced by ischemia. This study provides a modern pharmacological basis for the application of TSTT in managing ischemic stroke.
ETHNOPHARMACOLOGICAL RELEVANCE: Trillium tschonoskii rhizome (TTR), a medicinal herb, has been traditionally used to treat traumatic brain injury and headache in China. Although the potential neuroprotective efficacy of TTR has gained increasing interest, the pharmacological mechanism remains unclear. Steroidsaponins are the main bioactive components of the herb. AIM OF THE STUDY: To investigate the protective and repair-promoting effects of the total saponins from TTR (TSTT) on grey and white matter damages in a rat model of middle cerebral artery occlusion (MCAO) using magnetic resonance imaging (MRI) assay. MATERIALS AND METHODS:Ischemic stroke was induced by MCAO. TSTT and Ginaton (positive control) were administered orally to rats 6h after stroke and daily thereafter. After 15 days of treatment, the survival rate of each group was calculated. We then conducted neurological deficit scores and beam walking test to access the neurological function after ischemic stroke. Subsequently, T2-weighted imaging (T2WI) and T2 relaxometry mapping were performed to measure infarct volume and grey and white matter integrity, respectively. Moreover, diffusion tensor imaging (DTI) was carried out to evaluate the grey and white matter microstructural damage. Additionally, arterial spin labelling (ASL) - cerebral blood flow (CBF) and magnetic resonance angiography (MRA) images provided dynamic information about vascular hemodynamic dysfunction after ischemic stroke. Finally, haematoxylin and eosin (HE) staining was carried out to evaluate the stroke-induced pathological changes in the brain. RESULTS: The survival rate and neurological behavioural outcomes (Bederson scores and beam walking tests) were markedly ameliorated by TSTT (65mg/kg) treatment within 15 days after ischemic stroke. Moreover, T2WI and T2 relaxometry mapping showed that TSTT (65mg/kg) significantly reduced infarct volume and attenuated grey and white matter injury, respectively, which was confirmed by histopathological evaluation of brain tissue. The results obtained from DTI showed that TSTT (65mg/kg) not only significantly alleviated axonal damage and demyelination, but also promoted axonal remodelling and re-myelination. In addition, TSTT treatment also enhanced vascular signal density and increased CBF in rats after MCAO. CONCLUSION: Our results suggested the potential protective and repair-promoting effects of TSTT on grey and white matter from damage induced by ischemia. This study provides a modern pharmacological basis for the application of TSTT in managing ischemic stroke.
Keywords:
Grey matter; Ischemic stroke; Magnetic resonance imaging; Middle cerebral artery occlusion; Paris saponin VI (PubChem CID:71307571); Paris saponin VII (PubChem CID:101890253); Pennogenin-3-O-α-L-rhamnopyranosyl-(1→4)-[O-α-L- rhamnopyranosyl-(1→2)]-O-β-D-glucopyranoside; Pennogenin-3-O-β-D-glucopyranoside; Polyphyllin V (PubChem CID:101377612); Total saponins; Trillium tschonoskii rhizome; White matter