Effect of "Tongdu Qishen" acupuncture on expressions of ferroptosis-related factors in the hippocampus of APPswe/PS1dE9 Mice.

Objectives: To investigate the effect of "Tongdu Qishen" acupuncture［dredging the Govern Vessel and normalizing mental activities, electroacupuncture (EA) of "Baihui" (GV20), "Yintang" (EX-HN3) and "Shuigou" (GV26) needling］on the learning-memory ability and the mechanism of ferroptosis in Alzheimer's disease (AD) mice.

Methods: Twenty-four male APPswe/PS1dE9 mice were randomly and equally divided into model group and EA group, and 12 normal C57BL/6 mice were used as the control group. In the EA group, EA (2 Hz/100 Hz, 20 min) was applied to GV20 and EX-HN3 in combination with manual acupuncture stimulation of GV26. The treatment was performed once a day, for a total of 28 days. The mice in the three groups were given the same fixation and grasping operation. Morris water maze swimming tests were used to assess the mice's learning-memory ability. Nissl staining and transmission electron microscopy were used to observe the morphological changes of neurons in the hippocampus. The activity of superoxide dismutase (SOD) in the hippocampus tissue was detected by superoxide anionic colorimetric assay kit (WST-1), and malondialdehyde (MDA) contents were detected by thiobarbituric acid (TBA) method. The expression levels of prostaglandin endoperoxide synthase 2 (ptgs2) and glutathione peroxidase 4 (GPX4) mRNA in the hippocampus were detected by fluorescent quantitative real-time PCR.

Results: Behavioral results showed that compared with the control group, the escape latencies at the 2^nd, 3^rd, 4^th and 5^th day of Morris water maze swimming test were significantly increased (P<0.05), and the swimming time in the original platform quadrant and the times of cros-sing the original platform were considerably decreased (P<0.05) in the model group. In comparison with the model group, the escape latencies at the 4^th and 5^th day were strikingly decreased (P<0.05), and the swimming time in the original platform quadrant and times of crossing the original platform significantly increased (P<0.05) in the EA group. Following modeling, the SOD activity and the expression of GPX4 mRNA were obviously down-regulated (P<0.05), and the content of MDA and the expression of ptgs2 mRNA significantly up-regulated (P<0.05) in the model group rele-vant to the control group. The SOD activity and the expression of GPX4 mRNA were apparently increased (P<0.05), and the content of MDA and the expression of ptgs2 mRNA remarkably down-regulated (P<0.05) in the EA group rele-vant to the model group. Histopathological and ultrastructural results showed scattered arrangement of cells, widened space among cells, reduction in the number of cells, and many shrunk of dissolved nucleoli, shrunking and incomplete mitochondria, and high membrane electron density in the hippocampus of the model group, which was relatively milder in the EA group.

Conclusions: "Tongdu Qishen" acupuncture can improve the learning-memory ability of AD mice, which may be related to its functions in up-regulating SOD activity and GPX4 mRNA expression, and down-regulating MDA content and ptgs2 mRNA expression to reduce the lipid peroxidation in the process of ferroptosis.