Résumé
OBJECTIVE To explore the mechanism of Naozhenning granules in regulating mitochondrial energy metabolism in hippocampal tissue of multiple cerebral concussion （MCC） model rats. METHODS SPF grade Wistar rats were used to prepare MCC models using the “free fall impact method”. The successfully modeled rats were divided into model group， piracetam group， and Naozhenning granule low-dose， medium-dose and high-dose groups， and a normal group was also set up， with 8 rats in each group. Rats in each treatment group orally administered corresponding drugs at doses of 0.324 g/kg for the piracetam group and 2.25， 4.5 and 9 g/kg for the Naozhenning granule low-dose， medium-dose and high-dose groups； the normal group and model group were given equal volumes of normal saline； once a day， for 14 consecutive days. The motor exploration ability， learning and memory ability of rats were tested； the adenosine triphosphate （ATP） content in the hippocampal tissue of rat was detected； the changes in the mitochondrial structure of hippocampal tissue was observed； the fluorescence intensity of mitochondrial dynamin- related protein 1 （Drp1）， mitochondrial fission protein 1 （Fis1）， mitochondrial fusion 1 （Mfn1）， and optic atrophy protein 1 （Opa1） were detected in the hippocampal tissue of rat； the protein expression levels of peroxisome proliferator activated receptor gamma coactivator-1α（PGC-1α）， nuclear respiratory factor-1（NRF-1），mitochondrial transcription factor A（TFAM）， Wnt-3a，β-catenin in hippocampal tissue of rat were detected. RESULTS Compared with the normal group， the total exercise distance， number of central grid entries， number of upright positions， new object recognition index， mitochondrial ATP content， fluorescence intensity of Mfn1 and Opa1， the protein expression levels of PGC-1α、NRF-1、TFAM、Wnt-3a、 β-catenin in the model group were significantly reduced （P＜0.01）， while the rest time and fluorescence intensity of Drp1 and Fis1 in hippocampal tissue were significantly increased （P＜0.01）. The results of transmission electron microscopy showed that the mitochondria in the hippocampal tissue were significantly swollen， with a large number of broken and reduced cristae， and some mitochondria had myeloid changes in the membrane. Compared with the model group， the levels/contents of the above indicators in rats of each administration group showed varying degrees of reversal， and most of the differences were statistically significant （P＜0.05 or P＜0.01）； the degree of mitochondrial swelling in the hippocampal tissue was reduced， with a small amount of broken and reduced cristae， fuzzy fractures appeared in local areas of the rough endoplasmic reticulum. CONCLUSIONS Naozhenning granules can improve the motor exploration， learning and memory abilities of MCC model rats， repair neuronal damage， and exert neuroprotective effects. Its mechanism may be related to activating Wnt/β-catenin signaling pathway，maintaining the balance of mitochondrial division and fusion，and promoting mitochondrial biosynthesis.
Résumé
ObjectiveTo explore the effects of Naozhenning granules on the memory function and neuron cells in the rat model of post-concussion syndrome based on mitochondrial biosynthesis. MethodSPF-grade Wistar rats were used to establish the multiple cerebral concussion （MCC） model by the weight-drop method. The successfully modeled rats were assigned into model， piracetam （0.324 g·kg-1）， and low-， medium-， and high-dose （2.25， 4.5， and 9 g·kg-1， respectively） Naozhenning groups. The rats were administrated with corresponding drugs by gavage and those in the blank group and model group were administrated the same volume of normal saline once a day for 14 days. The general state of rats was observed before and after treatment. The open field test and new object recognition test were conducted to examine the motor and memory abilities of rats. Hematoxylin-eosin staining was employed to observe the pathological changes of cortical neurons in rats. Western blot and real-time polymerase chain reaction were employed to determine the protein and mRNA levels， respectively， of peroxisome proliferator-activated receptor γ-coactivator-1α （PGC-1α）， nuclear respiratory factor-1 （NRF-1）， and transcription factor A mitochondrial （TFAM） in rat cortex. ResultCompared with the blank group， the model group showed anxious and manic mental status， yellow and messy fur， and reduced food intake. In the open field experiment， the model group showed reduced total movement distance， times of entering the central grid， and times of rearing decreased and increased resting time compared with the blank group （P<0.01）. The model group had lower recognition index of new objects than the blank group （P<0.01）. In addition， the modeling caused reduced neurons with sparse distribution and deformed， broken， and irregular nucleoli and down-regulated the mRNA and protein levels of PGC-1α， NRF-1， and TFAM in the cortex （P<0.01）. Compared with the model group， piracetam and Naozhenning improved the mental state， coat color， food intake， and activities of rats. In the open field test， piracetam and Naozhenning increased the total movement distance， the times of entering the central grid， and the times of rearing and shortened the resting time （P<0.05， P<0.01）. The piracetam and Naozhenning groups had higher recognition index of new objects than the model group （P<0.05， P<0.01）. Compared with the model group， the piracetam and Naozhenning groups showed increased neurons with tight arrangement and large and round nuclei， and some cells with irregular morphology and turbid cytoplasm. Furthermore， piracetam and medium-dose Naozhenning upregulated the protein levels of PGC-1α， NRF-1， and TFAM （P<0.01）. Low-dose Naozhenning upregulated the protein levels of NRF-1 and TFAM （P<0.01）， and high-dose Naozhenning upregulated the protein levels of PGC-1α and TFAM in the cortex （P<0.01）. The mRNA levels of PGC-1α， NRF-1， and TFAM in the cortex were upregulated in the piracetam group and Naozhenning groups （P<0.05， P<0.01）. ConclusionNaozhenning granules can improve the motor， memory， and learning， repair the neuronal damage， and protect the nerve function in the rat model of MCC by promoting mitochondrial biosynthesis.
Résumé
0.05) but there was significant difference between CARG group and control group(P