ABSTRACT
ObjectiveTo investigate the effect of Rehmanniae Radix Praeparata on neurological function injury in ischemic stroke rats and explore its mechanism. MethodMale SD rats were randomized into sham operation， model， low- and high -dose （3.5 g·kg-1 and 7 g·kg-1） Rehmannia Radix Praeparata， and nimodipine （0.01 g·kg-1） groups. The rat model of middle cerebral artery occlusion （MCAO） was established with the modified suture occlusion method. Zea-Longa 5-point scoring was employed to evaluate the neurological function of rats. The cerebral infarction volume was detected by 2，3，5-triphenyltetrazolium chloride （TTC） staining. Hematoxylin-eosin staining and Nissl staining were employed to observe the morphology and damage of the brain tissue. Meanwhile， the serum levels of lactate dehydrogenase （LDH）， oxidative stress-related indicators superoxide dismutase （SOD）， glutathione peroxidase 4 （GPX4）， and malondialdehyde （MDA）， and the iron （Fe） content in the brain tissue were determined. To explore the mechanism of Rehmanniae Radix Preparata in mitigating the neurological damage in ischemic stroke rats， Western blotting was employed to determine the expression levels of proteins in the ischemic brain tissue. The autophagy-associated proteins included autophagy effector （beclin-1）， microtubule-associated protein light chain 3 （LC3B）， and ubiquitin-binding protein p62 （p62）. The ferroptosis-associated proteins included transferrin （TF）， transferrin receptor 1 （TFR1）， ferritin heavy chain 1 （FTH1）， and ferropotin （FPN1）. The neurological function injury-associated proteins included brain-derived neurotrophic factor （BDNF） and tyrosine kinase receptor B （TrkB）. ResultCompared with the sham operation group， the model group showed increased neurological function score， cerebral infarction volume， and appearance of nuclear pyknosis and vacuole of cells in the cerebral cortex. In addition， the model group presented elevated levels of LDH， MDA， and Fe （P<0.01） and lowered levels of SOD and GPX4 （P<0.01）. Compared with the model group， Rehmanniae Radix Praeparata decreased the content of LDH， MDA， and Fe （P<0.05， P<0.01） and elevated the levels of SOD and GPX4 （P<0.05， P<0.01）. Compared with the sham operation group， the modeling promoted the expression of beclin-1，LC3B Ⅱ/Ⅰ， TF， and TFR1 and inhibited the expression of p62， FTH1， FPN1， BDNF， and TrkB （P<0.01）. The expression levels of these proteins were recovered after the treatment with Rehmanniae Radix Praeparata. ConclusionRehmanniae Radix Praeparata may inhibit ferroptosis and improve the neurological function in ischemic stroke rats by down-regulating the autophagy level in the brain tissue.