Acupuncture plus moxibustion intervention improves learning-memory ability by suppressing hippocampal JAK2/STAT3 signaling in Alzheimer's rats

Abstract

To investigate the effect of acupuncture plus moxibustion on learning-memory ability and expression of hippocampal Janus kinase-2 (JAK2)/signal transducer and activator of transcription-3 (STAT3)/suppressors of cytokine signaling-3 (SOCS3) signaling in Alzheimer's Disease (AD) rats, so as to reveal their mechanisms underlying improvement of AD. A total of 60 SD rats were randomly divided into four groups：normal control, sham-operation, model and acupuncture-moxibustion (Acu-moxi, n＝15 in each group) groups. The AD model was established by microinjection of β-amyloid 1-42(Aβ1-42，5 µL)into the bilateral hippocampus. Seven days after modeling, Acu-moxi intervention was given. After insertion of acupuncture needles into "Baihui" (GV20) and bilateral "Shenshu" (BL23) and manipulating them for a while, the needles were then retained for 15 min, when, the mild moxibustion was performed at the same time. The treatment was conducted once daily, 5 times a week for consecutive 4 weeks. After the treatment, Morris water maze test was used to detect the animals' learning-memory ability. Immunohistochemistry and Western blot were respectively used to detect the number of positive cells and protein expression levels of JAK2, STAT3 and SOCS3 in the hippocampus tissue. Following modeling and compared with the normal control and sham-operation groups, the average escape latency was significantly prolonged (P<0.01), and the number of the original platform crossing and the residence time in the platform quadrant were significantly shortened in the model group (P<0.01). The numbers of hippocampal JAK2- and STAT3-positive cells and expression levels of hippocampal JAK2 and STAT3 proteins were significantly increased (P<0.01), and the number of hippocampal SOCS3-positive cells as well as the expression of SOCS3 protein significantly decreased in the model group relevant to the normal control and sham-operation groups (P<0.01). After the intervention, the average escape latency was significantly shortened (P< 0.01), and the number of the original platform crossing and the residence time in the platform quadrant were significantly increased in the Acu-moxi group (P<0.01), and the expression levels of JAK2 and STAT3 were significantly down-regulated and that of SOCS3 was considerably up-regulated in the Acu-moxi group relevant to the model group (P<0.01)．. Acu-moxi intervention can improve the learning-memory ability in AD rats, which is associated with its functions in inhibiting hippocampal JAK2/STAT3 signaling and up-regulating SOCS3 (a negative feedback factor) protein level.