[Effect of Huayu Tongluo moxibustion combined with neural stem cell transplantation on hippocampal Drp1/Mfn proteins and mitochondrial dynamics in rats with vascular dementia].

OBJECTIVES

To investigate the mechanism by which Huayu Tongluo moxibustion (HYTLM) regulates mitochondrial dynamics of neural stem cells (NSCs) for treatment of vascular dementia (VD).

METHODS

Seventy-two SD rats were randomized equally into 6 groups, including a sham-operated group, a VD model group, and 4 VD groups receiving HYTLM treatment, HYTLM treatment with stereotactic injection of NSC suspension into the hippocampal CA1 region, or injections of NSC suspension or cell culture medium without HYTLM treatment. Morris water maze test was used to assess learning and memory ability of the rats. Hippocampal neuronal apoptosis, NSC differentiation, neuronal survival, histopathological changes, mitochondrial reactive oxygen species (ROS) levels, and hippocampal expressions of Drp1, Mfn1, Mfn2, and Fis1 proteins were evaluated using TUNEL assay, immunofluorescence staining, HE staining, flow cytometry, and Western blotting.

RESULTS

The rats receiving culture medium injection, similar to the VD rats, exhibited prolonged escape latency and disorganized swimming trajectories in Morris water maze test and had significantly increased neuronal apoptosis, suppressed NSC proliferation, reduced mature neurons, impaired neurogenesis, and increased ROS levels in the hippocampal CA1 region, showing also obvious neuronal injuries, lowered hippocampal Drp1, Mfn1, and Mfn2 expressions and increased Fis1 expression. All these changes were significantly alleviated in VD rats receiving NSC transplantation. HYTLM treatment produced similar effects to NSC transplantation, but their combined treatment further shortened the escape latency of the VD rats, which showed similar swimming patterns to the sham-operated rats, and produced stronger protective effects on the hippocampal neurons. The combined treatment also further reduced ROS levels and improved aberrant expressions of Drp1, Mfn1, Mfn2, and Fis1.

CONCLUSIONS

HYTLM treatment improves cognitive functions of VD rats, promotes NSC differentiation into functional neurons and neuronal survival, and attenuates neuronal injury possibly by regulating hippocampal mitochondrial dynamics, thereby restoring mitochondrial homeostasis and ameliorating functional impairment.