Protective Effects of Chinese Herbal Medicine Rhizoma drynariae in Rats After Traumatic Brain Injury and Identification of Active Compound

Abstract

Traumatic brain injury (TBI) is a leading cause of death and disability in the USA. Effective therapeutic strategies for TBI are needed, and increasing attention is turning toward traditional herbal medicine. Rhizoma drynariae is a traditional Chinese medicine that has immunomodulatory and anti-inflammatory effects. Here, using the controlled cortical impact model of TBI in rats, we examined whether oral administration of R. drynariae can reduce TBI-induced brain injury in rats. We also identified the likely active compound among its four major phytochemicals in decoction. We found that post-treatment with R. drynariae decreased brain lesion volume, improved neurologic and cognitive function, and reduced anxiety- and depression-like behaviors. These changes were accompanied by reduced blood levels of IL-6 and increased IL-10. R. drynariae treatment also reversed the TBI-induced decrease in blood monocyte numbers and percentage of blood CD3 and CD4 T lymphocytes while inhibiting microglial/macrophage activation. Furthermore, by using ultra performance liquid chromatography and comparing retention times with authentic standards, we identified eriodictyol as the putative active compound of R. drynariae extract in the blood of rats with TBI. These novel findings indicate that the traditional Chinese herbal medicine R. drynariae protects brain against TBI-induced brain injury, possibly via immune-promoting, anti-inflammatory, and neuroprotective effects. Eriodictyol could be its active compound.

Environmental Circadian Disruption Worsens Neurologic Impairment and Inhibits Hippocampal Neurogenesis in Adult Rats After Traumatic Brain Injury

“…Cognitive functions were evaluated with the Morris water maze (MWM) test as described previously (Vorhees and Williams 2006; Wang et al 2015). Briefly, a rat was placed in a large circular pool (130 cm in diameter and 60 cm high) filled with warm (19–22 °C) water to a depth of 30 cm.…”

Endoplasmic Reticulum Stress and NF-κB Pathway in Salidroside Mediated Neuroprotection: Potential of Salidroside in Neurodegenerative Diseases

“…Therefore, a promising therapeutic strategy used for neurodegenerative diseases was focused on blocking microglial activation processes (Kim and Joh, 2006;Yuan et al, 2016). Recently, numerous studies have reported that traditional Chinese medicine exert neuroprotective effects through suppressing microglial activation, and their effects have been elevated to have the potential to treat neurodegenerative diseases Wang et al, 2016). Our present study demonstrated that salidroside, a central bioactive constituent of the traditional Chinese herb Rhodiola, significantly inhibits LPS-induced inflammation in microglial cells, and provided an underlying mechanism for the neuroprotective effects of Sal in microglia.…”

“…Rhodiola is a widely used TCM herb that has been shown to improve cognitive function, reduce mental fatigue, decrease free radicals, and enhance learning and memory (Darbinyan et al, 2000;Shevtsov et al, 2003). Salidroside (Sal) is the major phenylpropanoid glycoside extract from Rhodiola and has various bioactive effects, including anti-inflammatory, neuroprotective (Qu et al, 2012;Sun et al, 2012), attenuation of bleomycin-induced pulmonary fibrosis (Tang et al, 2016) and attenuation of arthritis-induced brain cognitive deficits (Zhu et al, 2016). Moreover, Sal could down-regulate NF-κB signaling pathways to prevent fibrosis and brain cognitive deficits (Tang et al, 2016;Zhu et al, 2016).…”

“…Salidroside (Sal) is the major phenylpropanoid glycoside extract from Rhodiola and has various bioactive effects, including anti-inflammatory, neuroprotective (Qu et al, 2012;Sun et al, 2012), attenuation of bleomycin-induced pulmonary fibrosis (Tang et al, 2016) and attenuation of arthritis-induced brain cognitive deficits (Zhu et al, 2016). Moreover, Sal could down-regulate NF-κB signaling pathways to prevent fibrosis and brain cognitive deficits (Tang et al, 2016;Zhu et al, 2016). The molecular mechanism behind the antiinflammation efficacy of Sal on activated-microglia may need further evaluation.…”

Rhein and rhubarb similarly protect the blood-brain barrier after experimental traumatic brain injury via gp91phox subunit of NADPH oxidase/ROS/ERK/MMP-9 signaling pathway

“…Herbal medicine plays a significant role in drug discovery and development11. Neuroscientists and doctors hope that novel chemical entities derived from herbal medicines could improve TBI treatment and reduce the risk of mortality and disability12.…”