人尿激肽原酶对SAMP8小鼠模型认知功能的影响及机制

Effect of human urinary kallidinogenase on cognitive function of SAMP8 mouse model and its mechanism

目的研究人尿激肽原酶(human urinary kallidinogenase,HUK)对SAMP8小鼠模型认知功能的影响及机制。方法SAMP8鼠分为5组:SAMP8组、治疗组(分别给予8.75×10^(-3)、1.75×10^(-2)、3.5×10^(-2)、7.0×10^(-2)PNAU·kg^(-1) HUK),并以SAMR1溶媒组作为空白对照。各组行Morris水迷宫检测空间认知水平,选取认知改善最明显一组(HUK组)进行后续实验。免疫组化检测CA3区ChAT表达情况,以RT-PCR进一步验证。Western blot检测PSD95、SYN、BDNF、pCREB蛋白表达。测定MPO活性及IL-1β、IL-18含量。结果SAMP8组小鼠的平台穿梭次数较SAMR1组减少(P<0.05),给予不同剂量HUK后,平台穿梭次数较SAMP8组增多(P<0.05或P<0.01),目的象限探索时间短(P<0.05或P<0.01),我们以7.0×10^(-2)PNAU·kg^(-1)剂量组(HUK组)进行后续实验。SAMP8组CA3区ChAT阳性细胞较SAMR1组表达明显减少;HUK组阳性细胞表达明显增多;RtPCR显示ChAT在SAMP8组表达明显低于SAMR1组,给予HUK治疗后ChAT表达明显高于SAMP8组。与SAMR1组比较,SAMP8组CA3区中IL-1β、IL-18含量、MPO活性明显升高,PSD95、SYN、BNDF和pCREB蛋白表达降低。经HUK干预后,IL-1β、IL-18含量及MPO活性降低,PSD95、SYN、BNDF和pCREB蛋白表达均增加。结论HUK改善SAMP8小鼠的空间认知功能,其机制可能是通过促进CA3区ChAT表达、减轻氧化应激水平及增加突触相关蛋白表达来实现。

Aim To study the effect of human urinary kallidinogenase(HUK)on the cognitive function of SAMP8 mouse model and its mechanism.Methods SAMP8 mice were divided intofive groups:SAMP8 group,treatment group(giving 8.75×10^(-3),1.75×10^(-2),3.5×10^(-2),7.0×10^(-2)HUK),and the SAMR1 vehicle group was used as blank control.Each group was performed Morris water maze to detect spatial cognition.Afterwards the group with the most obvious cognitive improvement(HUK group)was selected for the follow-up experiments.Immunohistochemical detection of ChAT expression in CA3 area was further verified by RtPCR.Western blot was used to detect the expression of PSD95,SYN,BDNF,and pCREB protein.The activity of MPO and the content of IL-1βand IL-18 were determined.Results The passing times in the SAMP8 group was less than that of the SAMR1 group(P<0.05).The passing times of treatment group increased compared with the SAMP8 group(P<0.05 or P<0.01),and the spatial probe time of the target quadrant was shorter(P<0.05 or P<0.01).We conducted follow-up experiments with group d(HUK group).The expression of ChAT positive cells in CA3 area of SAMP8 group was significantly lower than that of SAMR1 group;the expression of positive cells in HUK group significantly increased;RtPCR showed that ChAT expression in SAMP8 group was lower than that in SAMR1 group,and ChAT expression was significantly higher than that in SAMP8 group after HUK treatment.Compared with the SAMR1 group,the levels of IL-1β,IL-18 and MPO activity in the CA3 area of SAMP8 group significantly increased,and the protein expressions of PSD95,SYN,BNDF and pCREB decreased.After HUK treatment,the content of IL-1β,IL-18 and MPO activity decreased,and the expression of PSD95,SYN,BNDF and pCREB increased.Conclusions HUK can improve the spatial cognition of SAMP8 mice.The mechanism may be achieved by promoting the expression of ChAT in CA3 area,reducing the oxidative stress and increasing synapse-related proteins.