Effects of Danggui-Shaoyao-San on the Influence of Spatial Learning and Memory Induced by Experimental Tooth Movement

Abstract

Background:The pain caused by orthodontic treatment has been considered as tough problems in orthodontic practice. There is substantial literature on pain which has exactly effected on learning and memory; orthodontic tooth movement affected the emotional status has been showed positive outcomes. Danggui-Shaoyao-San (DSS) is a Traditional Chinese Medicine prescription that has been used for pain treatment and analgesic effect for orthodontic pain via inhibiting the activations of neuron and glia. We raised the hypothesis that DSS could restore the impaired abilities of spatial learning and memory via regulating neuron or glia expression in the hippocampus.Methods:A total of 36 rats were randomly divided into three groups: (1) Sham group (n = 12), rats underwent all the operation procedure except for the placement of orthodontic forces and received saline treatment; (2) experimental tooth movement (ETM) group (n = 12), rats received saline treatment and ETM; (3) DSS + ETM (DETM) group (n = 12), rats received DSS treatment and ETM. All DETM group animals were administered with DSS at a dose of 150 mg/kg. Morris water maze test was evaluated; immunofluorescent histochemistry was used to identify astrocytes activation, and immunofluorescent dendritic spine analysis was used to identify the dendritic spines morphological characteristics expression levels in hippocampus.Results:Maze training sessions during the 5 successive days revealed that ETM significantly deficits in progressive learning in rats, DSS that was given from day 5 prior to ETM enhanced progressive learning. The ETM group rats took longer to cross target quadrant during the probe trial and got less times to cross-platform than DETM group. The spine density in hippocampus in ETM group was significantly decreased compared to the sham group. In addition, thin and mature spine density were decreased too. However, the DSS administration could reverse the dendritic shrinkage and increase the spine density compared to the ETM group. Astrocytes activation showed the opposite trend in hippocampus dentate gyrus (DG).Conclusions:Treatment with DSS could restore the impaired abilities on ETM-induced decrease of learning and memory behavior. The decreased spines density in the hippocampus and astrocytes activation in DG of hippocampus in the ETM group rats may be related with the decline of the ability of learning and memory. The ability to change the synaptic plasticity in hippocampus after DSS administration may be correlated with the alleviation of impairment of learn and memory after ETM treatment.

Current advances in orthodontic pain

“…An animal study found that orthodontic pain could impair memory and learning through inducing hippocampal neuron apoptosis. 18 , 97 This finding was reinforced by another study in which chronic pain was revealed to interfere with memory formation in the hippocampus. 98 This effect of pain on the hippocampus may be a built-in strategy to alleviate chronic pain, but the effect on orthodontic pain in humans need to be validated in future studies.…”

“…Animal studies have indicated that orthodontic pain results in emotional stress 17 and transient learning and memory deficits. 18 …”

A narrative review of potential neural repair poststroke: Decoction of Chinese angelica and peony in regulating microglia polarization through the neurosteroid pathway

“…[ 31 ] Furthermore, DSS has shown potential in enhancing learning and memory abilities in female diabetic mice (db/db) and senescence-accelerated mice (SAM), likely by increasing the levels of estradiol (E2), nitric oxide (NO), and glycine. [ 32 33 ] The active ingredient in DSS, Z-ligustilide, has been associated with increased levels of neurosteroids, pregnenolone, and allopregnanolone, in brain tissue. [ 34 ] Intriguingly, previous network pharmacology studies have suggested that DSS might exert neuroprotective effects after stroke by modulating the steroid hormone signaling pathway and steroid hormone receptor activity, as evidenced by GO functional enrichment analysis and KEGG pathway enrichment analysis.…”