转基因阿尔茨海默病小鼠脑内炎症反应的诱发因素研究

目的 观察炎症反应在转基因阿尔茨海默病(AD)小鼠脑组织中的变化,探讨AD脑内炎症反应的诱发因素.方法 选用3、12个月龄转人β-淀粉样前体蛋白/早老素-1(APP/PS1)基因AD小鼠及正常野生型(WT)小鼠,分别应用免疫组织化学法和ELISA法观察脑内淀粉样斑块、炎性因子[白细胞介素(IL)-1β、IL-6、肿瘤坏死因子(TNF)α、前列腺素(PGE)2]的变化.结果 3个月龄APP/PS1基因AD小鼠脑组织中无淀粉样斑块沉积,未发现激活的星型胶质细胞和小胶质细胞,炎性因子IL-1β、IL-6、TNFα、PGE2的含量与WT小鼠差异无统计学意义(P均＞0.05).12个月龄转APP/PS1基因AD小鼠脑组织中有大量淀粉样斑块沉积,并伴有大量激活的星型胶质细胞和小胶质细胞,炎性因子IL-1β、IL-6、TNFα、PGE2的含量[分别为(56.02±9.04)、(8.66±0.83)、(97.48±26.58)、(72.18±21.01)ng/g]较WT小鼠[分别为(29.81±6.03)、(7.73±0.74)、(61.98±11.11)、(37.23±10.96)ng/g]及3个月龄转APP/PS1基因AD小鼠[分别为(30.05±3.53)、(7.43±1.17)、(59.34±10.47)、(42.56±5.93)ng/g]显著增加(P＜0.05或P＜0.01).结论 在淀粉样斑块形成之前,转APP/PS1基因AD小鼠脑组织中无明确的炎症反应;而淀粉样斑块沉积之后,脑组织中有显著的炎症反应;AD脑内炎症反应与淀粉样斑块形成密切相关,淀粉样蛋白(Aβ)沉积是导致脑内炎症反应的直接诱发因素.

Abstract：

Objective To observe the changes of cerebral inflammation-related markers in brain of a transgenic mouse model of Alzheimer's disease (AD) ,and to determine the causative factor to the development of cerebral inflammation in AD. Methods 3- and 12-month-old β-amyloid protein precursor ( APP)/presenilin (PSI) transgenic mice and age-matched wild-type mice (WT) were used in the study. The changes of amyloid plaques, inflammatory factors ( interleukin 1β ( IL-1β ); interleukin 6( IL-6 ); tumor necrosis factor α (TNFα) ;prostaglandin E2 (PGE2)) in the brains among these mice were measured by immunohistochemistry and ELISA. Results Immunohistochemical analysis revealed that no amyloid plaques and activated astrocytes as well as microglia were observed in the 3-month-old APP/PS1 mice. There were no significant differences in the levels of inflammatory factors (IL-1β, IL-6 ,TNFα,and PGE2) between the 3-month-old APP/PS1 and WT mice ( Ps ＞ 0. 05 ). However, abundant amyloid plaques accompanied by a remarkable increase of activated astrocytes and microglia were found in the brain of the 12-month-old APP/PS1 mice. The levels of inflammatory factors (IL-1β,IL-6,TNFα, and PGE2 ) were significantly increased in the 12-month-old APP/PS1 mice ([56. 02 ±9. 04] ng/g, [8. 66 ±0.83] ng/g, [97.48 ±26.58] ng/g, [72. 18 ±21.01] ng/g) than in the WT mice ([29. 18 ± 6. 03] ng/g, [7. 73 ± 0. 74] ng/g, [61.98 ±11.11] ng/g, [37. 23 ± 10. 96] ng/g) and the 3-month-old APP/PS1 mice ( [30. 05 ± 3.53] ng/g, [7.43 ± 1.17] ng/g, [59.34 ± 10. 07] ng/g, [42. 56 ±5.93] ng/g) (P＜0.05,or P＜0.01,respectively). Conclusion This study demonstrates that the APP/PS1mice did not show cerebral inflammation before the appearance of amyloid plaques, and exhibited remarkable inflammation after amyloid plaque deposition. These findings suggest that the induction of cerebral inflammation is tightly associated with amyloid plaque formation, and deposition of amyloid-beta protein (Aβ) may be the direct causative factor to the development of cerebral inflammation in AD.

Causative factor to cerebral inflammation in a transgenic mouse model of Alzheimer's disease

Objective To observe the changes of cerebral inflammation-related markers in brain of a transgenic mouse model of Alzheimer's disease (AD) ,and to determine the causative factor to the development of cerebral inflammation in AD. Methods 3- and 12-month-old β-amyloid protein precursor ( APP)/presenilin (PSI) transgenic mice and age-matched wild-type mice (WT) were used in the study. The changes of amyloid plaques, inflammatory factors ( interleukin 1β ( IL-1β ); interleukin 6( IL-6 ); tumor necrosis factor α (TNFα) ;prostaglandin E2 (PGE2)) in the brains among these mice were measured by immunohistochemistry and ELISA. Results Immunohistochemical analysis revealed that no amyloid plaques and activated astrocytes as well as microglia were observed in the 3-month-old APP/PS1 mice. There were no significant differences in the levels of inflammatory factors (IL-1β, IL-6 ,TNFα,and PGE2) between the 3-month-old APP/PS1 and WT mice ( Ps ＞ 0. 05 ). However, abundant amyloid plaques accompanied by a remarkable increase of activated astrocytes and microglia were found in the brain of the 12-month-old APP/PS1 mice. The levels of inflammatory factors (IL-1β,IL-6,TNFα, and PGE2 ) were significantly increased in the 12-month-old APP/PS1 mice ([56. 02 ±9. 04] ng/g, [8. 66 ±0.83] ng/g, [97.48 ±26.58] ng/g, [72. 18 ±21.01] ng/g) than in the WT mice ([29. 18 ± 6. 03] ng/g, [7. 73 ± 0. 74] ng/g, [61.98 ±11.11] ng/g, [37. 23 ± 10. 96] ng/g) and the 3-month-old APP/PS1 mice ( [30. 05 ± 3.53] ng/g, [7.43 ± 1.17] ng/g, [59.34 ± 10. 07] ng/g, [42. 56 ±5.93] ng/g) (P＜0.05,or P＜0.01,respectively). Conclusion This study demonstrates that the APP/PS1mice did not show cerebral inflammation before the appearance of amyloid plaques, and exhibited remarkable inflammation after amyloid plaque deposition. These findings suggest that the induction of cerebral inflammation is tightly associated with amyloid plaque formation, and deposition of amyloid-beta protein (Aβ) may be the direct causative factor to the development of cerebral inflammation in AD.