[Effects of Tongdu Tiaoshen acupuncture on depression-like behavior and Endophilin A1/ROS pathway in hippocampal tissue of CUMS model rats].

Abstract

Objective: To observe the effects of Tongdu Tiaoshen acupuncture (for unblocking the obstruction in the governor vessel and regulating the spirit) on depression-like behavior and the hippocampal Endophilin A1/reactive oxygen species (ROS) pathway in the chronic unpredictable mild stress (CUMS) model rats, and explore the mechanism of this therapy for depression.

Methods: Forty-eight male SD rats of SPF grade were randomly divided into a normal group (n=12) and a modeling group (n=36). In the modeling group, CUMS was performed to establish depression model. The successfully-modeled rats were randomized into a model group, a Tongdu Tiaoshen acupuncture group (referred to as the acupuncture group), and a fluoxetine group, with 12 rats in each group. In the acupuncture group, "Baihui" (GV20), "Shenting" (GV24), "Shuigou" (GV26) and "Dazhui" (GV14) were stimulated with acupuncture. This intervention measure was delivered once a day, continuously for 6 days; it was discontinued on day 7 and was completed in 28 days. In the fluoxetine group, intragastric administration was done with fluoxetine solution (2.1 mg/kg), once a day, and for 28 consecutive days. Before and after modeling, and after intervention completion, the body mass, sucrose preference rate and the total distance of movement and the boxes of horizontal crossing in the open field experiment were observed in each group. After intervention, using HE staining, the hippocampal neuron morphology was observed; using Nissl staining, the hippocampal Nissl body number was counted. The hippocampal mitochondria was observed under transmission electron microscopy. The average fluorescence intensity of ROS in hippocampal was determined using flow cytometry. With Western blot method, the protein expression of Endophilin A1, growth associated protein 43 (GAP-43), and brain-derived neurotrophic factor (BDNF) in hippocampal was detected; and with RT-qPCR method, the mRNA expression of Endophilin A1, GAP-43, and BDNF was recorded. Using the immunofluorescence, the average fluorescence intensity of Endophilin A1, GAP-43, and BDNF in hippocampal tissue was determined.

Results: Compared with the normal group, in the model group, the body mass, sucrose preference rate, and the total distance of movement and the boxes of horizontal crossing in the open field experiment decreased (P<0.01); the hippocampal neuronal structure was unclear, the matrix was relatively loose, and the number of Nissl body decreased (P<0.01); mitochondrial structure was disarranged, the outer membrane was ruptured, mitochondrial cristae was irregular or missed; the average fluorescence intensity of ROS in hippocampal tissue, the protein and mRNA expression and the average fluorescence intensity of Endophilin A1 in hippocampal tissue increased (P<0.01), while the protein and mRNA expression of GAP-43 and BDNF and its average fluorescence intensity decreased (P<0.01). Compared with the model group, the acupuncture group and the fluoxetine group showed the increase in body mass, sucrose preference rate, the total distance of movement and the boxes of horizontal crossing in the open field experiment (P<0.05, P<0.01); the hippocampal neuronal structure became relatively clear, the matrix was relatively dense, and the number of Nissl body was elevated (P<0.01); mitochondrial structure got normal and disarranged slightly, the average fluorescence intensity of ROS in hippocampal tissue, the protein and mRNA expression and the average fluorescence intensity of Endophilin A1 in hippocampal tissue were reduced (P<0.01), while the protein and mRNA expression of GAP-43 and BDNF and the average fluorescence intensity rose (P<0.01, P<0.05). Compared with the fluoxetine group, the acupuncture group presented the increase in the average fluorescence intensity of ROS, the protein expression and the average fluorescence intensity of Endophilin A1, the protein expression of GAP-43 and the mRNA expression of BDNF (P<0.01, P<0.05), and the decrease of the protein expression and the average fluorescence intensity of BDNF, the mRNA expression of Endophilin A1, and the average fluorescence intensity of GAP-43 (P<0.01, P<0.05).

Conclusion: Tongdu tiaoshen acupuncture alleviates depression-like behaviors in CUMS model rats and protects hippocampal neurons, which may be related to suppressing Endophilin A1/ROS signaling pathway and attenuating oxidative stress reactions.