Objective

2

To observe the therapeutic effect of gastrodin （GAS） on neural injury in hypertensive rats with vascular dementia （VaD） through the regulation of ferroptosis via the nuclear factor E2-related factor 2 （Nrf2）/glutathione peroxidase 4 （GPX4） signaling pathway.

Methods

2

Eight Wistar-Kyoto （WKY） rats were selected as the blank control group （WKY）. Fifty spontaneously hypertensive rats （SHR） were used to establish a model of hypertension combined with VaD via a modified bilateral vascular occlusion method. Forty successfully modeled rats were randomly divided into five groups： model group， donepezil group， high-dose （GAS-H） group， medium-dose （GAS-M） group， and low-dose （GAS-L） group， with 8 rats in each group. The WKY group and model group were administered 1 mL of physiological saline per 100 g of body weight daily by gavage. The donepezil group received 0.45 mg/（kg·d） donepezil by gavage. The GAS-H， GAS-M， and GAS-L groups received GAS tablets in solutions at 100， 50， and 25 mg/（kg·d）， respectively. All treatments were given for 4 consecutive weeks. After 4 weeks of administration， tissue samples were collected. The morphological changes in hippocampal tissue， iron deposition， and levels of Fe

2+

， malondialdehyde （MDA）， glutathione （GSH）， and protein expression of Nrf2， GPX4， 4-hydroxynonenal （4-HNE）， and cyclooxygenase-2 （COX-2） were compared across the groups.

Results

2

In the WKY group， the neurons were structurally normal， with abundant Nissl bodies. In the model group， neuronal necrosis was severe， with a significant decrease in Nissl bodies. In the donepezil group， neuronal necrosis was reduced and Nissl bodies increased. The GAS-H group showed significantly reduced neuronal necrosis and an increase in Nissl bodies. In the GAS-M and GAS-L groups， neuronal necrosis decreased to some extent， but the increase in Nissl bodies was not as pronounced. No blue i

ron deposition was observed in the WKY group， while significant iron deposition was found in the model group. Iron deposition was significantly reduced in the donepezil and GAS-H groups， while it decreased to a lesser extent in the GAS-M and GAS-L groups. Compared to the WKY group， the model group exhibited higher levels of Fe

2+

and MDA （

P

<

0.01） and lower levels of GSH （

P

<

0.05）. Compared to the model group， the donepezil， GAS-H， GAS-M， and GAS-L groups had lower levels of Fe

2+

and MDA （

P

<

0.05）， and higher levels of GSH （

P

<

0.05）. The levels of Fe

2+

and MDA followed the order： GAS-H

<

donepezil

<

GAS-M

<

GAS-L （

P

<

0.05）. GSH levels followed the order： GAS-H

>

donepezil

>

GAS-M

>

GAS-L （

P

<

0.05）. The relative expression of Nrf2 and GPX4 proteins in the model group was significantly lower than that in the WKY group （

P

<

0.01）. The donepezil， GAS-H， and GAS-M groups showed higher expression of Nrf2 and GPX4 compared to the model group （

P

<

0.01）. The order of relative protein expression of Nrf2 and GPX4 was： GAS-H

>

donepezil

>

GAS-M

>

GAS-L （

P

<

0.05）. Compared to the WKY group， the relative expression of 4-HNE and COX-2 in the model group was significantly higher （

P

<

0.01）. In the donepezil， GAS-H， and GAS-M groups， the expression of 4-HNE and COX-2 was significantly lower than that in the model group （

P

<

0.01）， and in the GAS-L group， the expression of 4-HNE was significantly lower （

P

<

0.05）. The order of protein expression for 4-HNE and COX-2 was： GAS-H

<

donepezil

<

GAS-M

<

GAS-L （

P

<

0.05）.

Conclusion

2

GAS may improve hippocampal neuronal injury in hypertensive rats with VaD by activating the Nrf2/GPX4 signaling pathway， increasing GSH levels， reducing COX-2， MDA， and 4-HNE production， and decreasing iron deposition.