Effects of Zuogui Jiangtang Jieyu Formula （左归降糖解郁方） on Dendritic Spines of Hippocampal Dentate Gyrus and Wnt5a/RhoA Signaling Pathway in Diabetic with Depression Model Rats / 中医杂志

ABSTRACT

ObjectiveTo explore the potential mechanism of Zuogui Jiangtang Jieyu Formula （左归降糖解郁方， ZJJF） for diabetic rats with depression. MethodsSixty rats were randomly divided into normal group， model group， wingless MMTV integration site family member 5a （Wnt5a） agonist group， ZJJF group， and ZJJF plus Wnt5a inhibitor group， with 12 rats in each group. Except for the normal group， the rats were fed with high-fat chow， streptozotocin injection， and chronic mild unpredictable stress combination， to establish model of diabetes mellitus complicated with depression. After successful modelling， rats in the Wnt5a agonist group were given bilateral hippocampal stereotactic injections of Wnt5a agonist Foxy-5 with 5 μl each for 7 consecutive days； rats in ZJJF group were given 20.52 g/（kg·d） of ZJJF by gavage； rats in ZJJF plus Wnt5a inhibitor group were given the drug by gavage， and bilateral hippocampal stereotactic injections of Wnt5a inhibitors Box5， with the same dosage and injection method as above. The normal group and model group were given 10 ml/（kg·d） of normal saline by gavage. All groups were gavaged for 4 consecutive weeks. At the end of the intervention， the depression-like behaviour of rats was evaluated using the forced swimming experiment （immobility time） and the absent field experiment （number of activities）； the blood glucose and insulin levels of rats were measured and the insulin resistance index was calculated； the dendritic morphology of dentate gyrus neurons in the hippocampus was observed using Golgi staining； the level of dentate gyrus neuron proliferation was measured using 5-bromodeoxyuracil nucleoside （Brdu） injection and immunofluorescence； RT-qPCR and Western blot were used to detect the mRNA and protein expression of Wnt5a， Ras homologue genomic member A （RhoA） and Rho homologue-associated coiled-coil protein kinase 1 （ROCK1） in the dentate gyrus. ResultsCompared with the normal group， rats in the model group had significantly higher blood glucose， insulin and insulin resistance indices， longer immobility time， fewer activities， lower Brdu integral optical density values and Wnt5a， RhoA， ROCK1 protein and mRNA expression in the dentate gyrus of the hippocampus （P＜0.05 or P＜ 0.01）； the dendritic branches of rat hippocampal dentate gyrus neurons could be seen to be significantly reduced or broken， and their length shortened. Compared with the model group， the blood glucose， insulin and insulin resistance indices of rats in ZJJF group and the ZJJF plus Wnt5a inhibitor group significantly reduced （P＜0.05 or P＜0.01）； the immobility time of rats in the Wnt5a agonist group and ZJJF group was significantly shortened， the number of activities increased， the Brdu integral optical density values elevated， and the Wnt5a， RhoA， ROCK1 protein and mRNA expression elevated （P＜0.05 or P＜0.01）， and the number of dendritic branches of hippocampal dentate gyrus neurons significantly increased， the length lengthened， and the complexity of dendrites increased. Compared with the Wnt5a agonist group， rats in the ZJJF group showed significant decrease in blood glucose， insulin and insulin resistance indices， prolongation of immobilisation time， reduction in the number of activities， and reduction in the Brdu integral optical density value； except for the Wnt5a mRNA in ZJJF group， Wnt5a， RhoA， ROCK1 protein and mRNA expression reduced in both ZJJF group and ZJJF plus Wnt5a inhibitor group （P＜0.05 or P＜0.01）. Compared with ZJJF group， Wnt5a， RhoA， ROCK1 protein and mRNA expression were reduced in ZJJF plus Wnt5a inhibitor group （P＜0.05 or P＜0.01）. ConclusionZJJF can improve hyperglycemia and depressive-like behaviours in rat models of diabetes with depression， and its antidepressant effects may be related to the activation of hippocampal Wnt5a/RhoA signaling and promotion of dentate gyrus neuron dendritic growth.