| Objective:to observe the effect of minocycline（minocycline）on blood pressure and plasma levels of interleukin-1 β（IL-1-β）,interleukin-6（IL-6）and norepinephrine（NE）in two-kidney-one-clip（2k1c）hypertensive rats,and to explore whether minocycline can regulate blood pressure by affecting inflammatory factors and neurotransmitters in hypothalamic paraventricular nucleus（PVN）.Methods:1.Animal grouping,modeling and catheterization:28 male SD rats weighing250g～270g were selected and randomly divided into four groups:1SHAM+aCSF group,2SHAM+minocycline group,32k1c+aCSF group and 42k1c+minocycline group.After one week of adaptive feeding,the models of coarctation of renal artery and catheterization of paraventricular nucleus were made in strict accordance with the requirements of each group:group 1 and group 2 were treated with hypothalamic paraventricular nucleus catheterization in the fifth week.Group 1 was given the same amount of artificial cerebrospinal fluidevery day（5ul）,and group2 was given the same amount of minocycline daily（5ul）for six weeks.Renal artery coarctation was performed in group 3 and group 4,and hypertension model was established one month later,followed by catheterization of paraventricular nucleus.After operation,the same amount of artificial cerebrospinal fluid was given in group3 and minocycline in group 4 for six weeks.（both sides of PVN are injected）2.The blood pressure was measured once a week by non-invasive blood pressure measurement.3.Detection of renal sympathetic nerve discharge（RSNA）:the sympathetic nerve discharge was measured and recorded before the rats were killed.4.Sample collection.5.The number of activated microglia and the length of processes were detected by immunofluorescence.6.The concentrations of IL-1β,IL-6,NE,GLU and GABA in PVN were detected by high performance liquid chromatography（HPLC）.7.The expression of gp91phoxmRNA in PVN was detected by real-time quantitative PCR.8.Plasma Levels of IL-1β、IL-1βand NE were determined by ELISA.Results:1.Effect of minocycline on blood pressure（SBP）:compared with SHAM group,the blood pressure of 2k1c group was significantly higher（P<0.05）.Compared with 2k1c+aCSF group,the blood pressure of 2k1c+minocycline group decreased significantly after PVN was infused with minocycline（P<0.05）.2.Effect of minocycline on microglia in PVN:compared with SHAM group,the number of activated microglia in 2k1c group was significantly increased,and the microglial processes were significantly shorter（P<0.05）.Compared with2k1c+aCSF group,the number of activated microglia in 2k1c+minocycline group was significantly decreased,and the microglial processes were significantly longer in 2k1c+minocycline group（P<0.05）.3.Effect of minocycline on the concentration of IL-1βin PVN:the level of IL-1βin PVN in 2k1c group was significantly higher than that in SHAM group（P<0.05）.Compared with 2k1c+aCSF group,the level of IL-1βin PVN of2k1c+minocycline group decreased significantly（P<0.05）.4.Effect of minocycline on the concentration of IL-6 in PVN:the level of IL-6in PVN in 2k1c group was significantly higher than that in SHAM group（P<0.05）.Compared with 2k1c+aCSF group,the level of IL-6 in PVN of 2k1c+minocycline group decreased significantly（P<0.05）.5.Effect of minocycline on the concentration of NE in PVN:the level of NE in PVN in 2k1c group was significantly higher than that in SHAM group（P<0.05）.Compared with 2k1c+aCSF group,the level of NE in PVN of 2k1c+minocycline group decreased significantly（P<0.05）.6.Effect of minocycline on the concentration of excitatory neurotransmitter GLU in PVN:the concentration of GLU in PVN in 2k1c group was significantly higher than that in SHAM group（P<0.05）.The GLU concentration of PVN in2k1c+minocycline group was significantly lower than that in 2k1c+aCSF group（P<0.05）.7.Effect of minocycline on the concentration of inhibitory neurotransmitter GABA in PVN:compared with SHAM group,the concentration of GABA in PVN in 2k1c group was significantly lower（P<0.05）.The GABA concentration of PVN in 2k1c+minocycline group was significantly higher than that in 2k1c+aCSF group（P<0.05）.8.Effect of minocycline on the expression of gp91phoxmRNA in PVN:the expression of gp91phoxmRNA in PVN of rats in 2k1c group was significantly higher than that in SHAM group（P<0.05）.Compared with 2k1c+aCSF group,gp91phoxmRNA in PVN of 2k1c+minocycline group decreased（P<0.05）.9.Effect of minocycline on plasma IL-1β:the level of plasma IL-1βin 2k1c group was significantly higher than that in SHAM group（P<0.05）.The level of plasma IL-1βin 2k1c+minocycline was significantly lower than that in 2k1c+aCSF group（P<0.05）.10.Effect of minocycline on plasma IL-6:the level of plasma IL-6 in 2k1c group was significantly higher than that in SHAM group（P<0.05）.The level of plasma IL-6 in 2k1c+minocycline was significantly lower than that in 2k1c+aCSF group（P<0.05）.11.Effect of minocycline on plasma norepinephrine（NE）:the level of plasma NE in 2k1c group was significantly higher than that in SHAM group（P<0.05）.The level of plasma NE in 2k1c+minocycline was significantly lower than that in2k1c+aCSF group（P<0.05）.12.Effect of minocycline on renal sympathetic nervous activity:compared with SHAM group,the renal sympathetic nervous activity in 2k1c group was significantly higher（P<0.05）.The renal sympathetic nervous activity in 2k1c+minocycline group was significantly lower than that in 2k1c+aCSF group（P<0.05）.Conclusion:1.PVN infusion of minocycline can gradually reduce two-kidney-one-clip hypertension.2.Minocycline can inhibit the activation of microglia and lengthen their processes.3.PVN infusion of minocycline can inhibit the release of central inflammatory cytokines IL-1βand IL-6 by inhibiting microglia,and decrease the expression level of NE,GLU and increase the expression level of GABA.3.Infusion of minocycline could inhibit the expression of gp91phoxmRNA in PVN.4.PVN infusion of minocycline can reduce the release of plasma inflammatory cytokines IL-1βand IL-6,as well as the expression level of plasma NE.5.Minocycline can attenuate renal sympathetic discharge. |
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