Study On The Role Of TREM2 In Microglia Activation Induced By Combined Exposure To Lead And Hypertension

Objectives In this study,lead exposure model of hypertension mice and a BV-2 cell model of microglia cell line exposed to lead and Ang II was established to investigate the role of TREM2 in microglia activation induced by lead and hypertension,and to provide a new basis for the prevention and treatment of nerve damage in hypertension induced by lead exposure.Methods 1 A total of 40 SPF grade male C57BL/6 mice were selected,of which 20 were injected intraperitoneally with Ang II to establish the model of hypertension.After that,non-hypertensive mice were randomly divided into control group and lead exposure group,and hypertensive mice were randomly divided into hypertension group and lead +hypertension group with 10 mice in each group.The mice in hypertension group and lead +hypertension group were fed with high salt diet(including 4% Na Cl),and the other two groups were fed with normal diet.Mice in lead exposure group and lead + hypertension group were given lead acetate drinking water at the concentration of 250 mg/L,while the other two groups were given pure water for 12 weeks.2 A total of 40 SPF grade male C57BL/6 mice were selected,of which 20 were injected intraperitoneally with Ang II to establish the model of hypertension.After that,non-hypertensive mice were randomly divided into control group and HSP60 control group.Hypertensive mice were randomly divided into lead + hypertension group and HSP60 + lead + hypertension group with 10 mice in each group.Mice in control group and HSP60 control group were fed with normal diet and purified water,while mice in lead + hypertension group and HSP60 + lead +hypertension group were fed with high salt diet and 250mg/L lead acetate drinking water for 12 weeks.Mice in HSP60 control group and HSP60 + lead + hypertension group(HSP60 intervention group)were intraperitoneally injected with HSP60 solution at the concentration of 1 μg/μL every two days in the last week.3 The neurobehavioral function was measured by Morris water maze,open field test and new object recognition test.4 HE staining was used to detect the pathological changes of hippocampus in experimental mice.5 The content of lead in whole blood and hippocampus of mice was detected by ICP-MS.6The microglia cell line BV-2 cell model was established by using lead acetate and Ang II.7CCK-8 method was used to detect the survival rate of BV-2 cells exposed to different concentrations of lead acetate and Ang II.8 Detection of TREM2 and Iba1 protein expression in tissues and cells by Western Blot.9 The expression of TREM2 and Iba1 m RNA in tissues and cells was detected by Real-time PCR.10 The expression of inflammatory factors IL-1β,IL-6 and TNF-α was measured by enzyme linked immunosorbent assay(ELISA).Results 1 After 12 weeks of lead acetate exposure,the results of water maze showed that the escape latency of lead + hypertension group was significantly higher than that of lead exposure group and hypertension group(P<0.05),and the open field test showed that the standing times and central area stay time of lead + hypertension group were significantly lower than those of lead exposure group and hypertension group(P<0.05).The results of new object recognition experiment showed that the new object recognition index of lead +hypertension group was significantly lower than that of hypertension group(P<0.05).2The content of lead in whole blood and hippocampus in lead exposure group and lead +hypertension group was significantly higher than that in control group and hypertension group(P<0.05).3 Compared with the control group,the arrangement of hippocampal neurons in the lead + hypertension group was more disordered,the nucleus was deeply stained and the arrangement was loose.4 Compared with the control group,the levels of inflammatory factors IL-1β,IL-6 and TNF-α in hippocampus of mice in hypertension group and lead exposure group increased.Compared with the hypertension group and the lead exposure group,the levels of inflammatory factors IL-1β,IL-6 and TNF-α in the hippocampus of the lead+hypertension group increased(P<0.05).5 Compared with hypertension group and lead exposure group,the expression of Iba1 protein and m RNA in hippocampus of lead + hypertension group was significantly increased(P<0.05).6Compared with the control group,the expressions of inflammatory factors IL-1β,IL-6 and TNF-α in BV-2 cells in lead exposure group and Ang II group increased.Compared with lead exposure group and Ang II group,the expression of inflammatory factors IL-1β,IL-6and TNF-α in BV-2 cells in Ang II + lead exposure group increased(P<0.05).7 After BV-2cells were exposed to lead and Ang II,the expression of Iba1 protein and m RNA in Ang II +lead exposure group was higher than that in Ang II group and lead exposure group,while the expression of TREM2 protein and m RNA decreased(P<0.05).8 Compared with Ang II+ lead exposure group,the expression of TREM2 protein and m RNA in BV-2 cells in HSP60 intervention group was significantly higher than that in Ang II + lead exposure group(P<0.05).9 Compared with lead + Ang II group,the expression of inflammatory cytokines IL-1β,IL-6 and TNF-α in BV-2 cells in HSP60 intervention group decreased(P<0.05).10 Compared with lead + hypertension group,the expression of TREM2 protein and m RNA in hippocampus of mice in HSP60 intervention group increased(P<0.05).11 The results of the water maze of HSP60 intervention in lead-exposed hypertensive mice showed that compared with the lead + hypertension group,the number of times of crossing the platform of the mice in the HSP60 intervention group was increased(P<0.05).Compared with the hypertensive group,the HSP60 intervention group showed an increase in the residence time and the number of standing times in the central area of the mice(P<0.05).The results of the novel object recognition experiment showed that compared with the lead + hypertension group,the novel object recognition index of the mice in the HSP60 intervention group increased(P<0.05).12 The expression of inflammatory cytokines IL-1β,IL-6 and TNF-α in hippocampus of lead exposed hypertensive mice were significantly decreased after HSP60 intervention(P<0.05).Conclusions Lead exposure can aggravate the neuroinflammatory reaction and neurobehavioral damage in hypertensive mice,at the same time,the expression of Iba1 in hippocampus of mice increases,microglia activation increased,and the intervention of TREM2 receptor agonist HSP60 can reduce the neuroinflammatory damage in hypertensive mice exposed to lead.Figure 17;Table 12;Reference 97...