Effect of Gouteng Jiangya Jieyu Perscription on Polarization of Hippocampal Microglia in Hypertensive Rats Complicated with Depression by Inhibiting TLR4/NF-кB Signaling Pathway / 中药新药与临床药理

ABSTRACT

Objective To investigate the effect of Gouteng Jiangya Jieyu Perscription(Uncariae Ramulus cum Uncis,Gastrodiae Rhizoma,Pheretima,Puerariae Lobatae Radix,etc.)modulating the TLR4/NF-кB signaling pathway on the polarization of hippocampal microglia in rats with hypertension complicated with depression(HD)Methods Forty primary hypertensive rats were randomly divided into five groups:the model group,the positive drug group,and the high-,medium-,and low-dose groups of Gouteng Jiangya Jieyu Perscription,with 8 rats in each group;and another 8 SD rats were taken as the control group.The HD model was replicated using 42 days of continuous chronic unpredictable mild stress(CUMS)combined with solitary rearing.The modeling was accompanied by the administration of drugs,including 29.61,14.81,and 7.40 g·kg-1 of Gouteng Jiangya Jieyu Perscription in the high-,medium-,and low-dose groups of Chinese herbal medicine,respectively,and 0.45 mg·kg-1 of Levamlodipine Besylate+1.8 mg·kg-1 of Fluoxetine in the positive group;the volume of the gavage was 10 mL·kg-1,once a day,for 42 consecutive days.The systolic blood pressure of rat tail artery was measured by non-invasive sphygmomanometer before drug administration and in the morning of the last day of each week;the behavioural test of Sucrose Preference Test(SPT)was carried out once in the second week and once in the last week after the start of the modelling;the water maze experiment was carried out after the end of the modelling;the levels of serum inflammatory factor tumor necrosis factor-α(TNF-α),interleukin(IL)1β and IL-10 were determined by ELISA;the pathological changes of rat hippocampal tissue neurons were observed by HE staining and Nissl stain were used to observe the neuronal pathological changes in rat hippocampal tissue;immunofluorescence double staining was used to detect the expressions of microglia M1(CD16)and M2(CD206)types in the hippocampal region;and Western Blot was used to detect the protein expressions of TLR4 and NF-кB p65 in the hippocampal tissue.Results Compared with the control group,the systolic blood pressure in the tail artery of rats in the model group from week 1 to week 6 were all significantly increased(P＜0.01);sucrose preference rate was significantly decreased(P＜0.01);evasion latency was significantly prolonged(P＜0.05,P＜0.01),the number of times of traversing the plateau and the percentage of time spent in the target quadrant were significantly decreased(P＜0.01);the contents of serum TNF-α and IL-1β were significantly increased(P＜0.01),IL-10 content was significantly decreased(P＜0.01);cytosolic nuclei were deeply stained,cytoplasmic solidification and apoptosis were obvious;the fluorescence intensity ratio of CD206/CD16 in hippocampal microglial cells were significantly decreased(P＜0.05);the protein expressions of TLR4 and NF-кB p65 in hippocampal tissues were significantly up-regulated(P＜0.01).Compared with the model group,the systolic blood pressure in the tail artery of rats in the first to sixth weeks of the drug administration group were all significantly reduced(P＜0.01);the sucrose preference rates were all significantly increased(P＜0.05);the contents of serum TNF-α and IL-1β were significantly decreased(P＜0.01),and the content of IL-10 was significantly increased(P＜0.01);the Nissl substances are abundant and apoptosis is significantly reduced,and apoptosis were significantly reduced.The escape latency of rats in the positive drug group and the high-dose group of Gouteng Jiangya Jieyu Perscription was significantly shortened(P＜0.05,P＜0.01),and the number of times of crossing the plateau and the percentage of time spent in the target quadrant were significantly increased(P＜0.05);the ratio of fluorescence intensity of hippocampal microglial cells,CD206/CD16 was significantly increased(P＜0.05,P＜0.01);and the hippocampal tissues,protein expressions of TLR4 and NF-κB p65 were significantly down-regulated(P＜0.05,P＜0.01).Conclusion Gouteng Jiangya Jieyu Perscription may regulate the polarisation state of hippocampal microglial cells,modulate the secretion of inflammatory factors,and attenuate the damage of hippocampal neurons in HD rats by inhibiting the TLR4/NF-кB pathway.