小鼠品系和小鼠年齡對實驗數(shù)據(jù)的影響知多少？

?實驗小鼠是進行科學(xué)研究常用的實驗動物，小鼠不僅和人的基因具有相似度，而且具有體型小、易飼養(yǎng)、生長繁殖快、操作管理方便的優(yōu)點。隨著小鼠在科學(xué)研究中的廣泛應(yīng)用，科研人員培育出了許多小鼠品種及品系。在進行研究計劃時，選擇合適品系的小鼠建立動物疾病模型，是實驗設(shè)計的關(guān)鍵基礎(chǔ)一步。

BALB/c小鼠?：

?遺傳背景?：1913年美國國立腫瘤研究所培育，經(jīng)過多代近交繁殖。

?特征?/用途?：?

1.性格溫順，易于繁殖，雌雄體重差異小；

2.乳腺腫瘤發(fā)病率低(3％)，當(dāng)用乳腺腫瘤病毒(MTV)誘導(dǎo)時發(fā)病率將增高。對礦物油誘導(dǎo)漿細胞瘤敏感，廣泛應(yīng)用于雜交瘤和單克隆抗體的生產(chǎn)；

3.易患慢性肺炎；

4.有自發(fā)高血壓癥，老年鼠心臟病變，雌雄鼠均有動脈硬化，幾乎全部20月齡的雄鼠脾臟均有淀粉樣變；

5.對放射線敏感，應(yīng)用于核醫(yī)學(xué)。

?C57BL/6小鼠?：

?遺傳背景?：1921年C.C.Little用Abby Lathrop小鼠培育而成。

?特征?/用途?：

1.已經(jīng)完成基因組測序的小鼠品系；

2.品系穩(wěn)定、容易繁殖；

3.試驗結(jié)果精度高，可比性好，應(yīng)激反應(yīng)均一；

4.構(gòu)建基因修飾動物模型，可保證遺傳背景的高度穩(wěn)定性和實驗數(shù)據(jù)一致性。

有了這些基礎(chǔ)知識背景，我們在構(gòu)建模型時，設(shè)計實驗時，參考文獻時，評價數(shù)據(jù)時，就能更準(zhǔn)確。尤其我們使用荷蘭Liposoma巨噬細胞清除劑Clodronate Liposomes氯膦酸鹽脂質(zhì)體清除巨噬細胞時，我們除了關(guān)注這些因素，還需要考慮小鼠的周齡。巨噬細胞的高度異質(zhì)性和可塑性，也覺得巨噬細胞的多功能性和多面性，動態(tài)性和適應(yīng)性。比如巨噬細胞可以質(zhì)控造血干細胞（見Science文獻），巨噬細胞可以和神經(jīng)元一樣調(diào)控運動（見Natuer文獻）。在這些頂刊的重大研究發(fā)現(xiàn)中，研究人員都使用荷蘭Liposoma的巨噬細胞清除劑（CP-005-005）貨號。此外，巨噬細胞等免疫細胞，在不同品系，不同周齡，不同性別，也是差異很大。見如下這篇文獻的基礎(chǔ)研究。

小鼠選擇

品系：C57BL/6和BALB/c

性別：雄性鼠

周/月齡：1、3、5、10和18月齡

處死方式：通過CO2窒息處死

樣品：外周血和脾臟

流式細胞術(shù)分析

1、樣本制備:

外周血單個核細胞(PBMC):血液PBS稀釋后,使用ACK裂解液去除紅細胞•脾細胞:機械分離后同樣使用ACK裂解液處理

2、抗體標(biāo)記: 使用熒光標(biāo)記的單克隆抗體組合:

FITC標(biāo)記: CD4、CD19、MHC II、CD11b

PE標(biāo)記: CD3、CD8、CD11c、CD44

PerCP標(biāo)記: CD3、CD19

研究結(jié)果

參考文獻：

Pinchuk LM, Filipov NM. Differential effects of age on circulating and splenic leukocyte populations in C57BL/6 and BALB/c male mice. Immun Ageing. 2008 Feb 11;5:1. doi: 10.1186/1742-4933-5-1. PMID: 18267021; PMCID: PMC2268915.

Results

Using a multipoint age comparison approach, cells from the two major immune system compartments, peripheral blood and spleen, and flow cytometry analysis, we found several principal differences in T cell and professional antigen presenting cell (APC) populations originating from a prototypical T helper (Th) 1 mouse strain, C57BL/6, and a prototypical Th2 strain, BALB/c. For example, regardless of age, there were strain differences in both peripheral blood mononuclear cells (PBMC) and spleens in the proportion of CD4+ (higher in the BALB/c strain), CD8+ T cells and CD11b+/CD11c+ APC (greater in C57BL/6 mice). Other differences were present only in PBMC (MHC class II + and CD19+ were greater in C57BL/6 mice) or differences were evident in the spleens but not in circulation (CD3+ T cells were greater in C57BL/6 mice). There were populations of cells that increased with age in PBMC and spleens of both strains (MHC class II+), decreased in the periphery and spleens of both strains (CD11b+) or did not change in the PBMC and spleens of both strains (CD8+). We also found strain and age differences in the distribution of na?ve and memory/activated splenic T cells, e.g., BALB/c mice had more memory/activated and less naive CD8+ and CD4+ T cells and the C57BL/6 mice.

Conclusion

Our data provide important information on the principal differences, within the context of age, in T cell and professional APC populations between the prototypical Th1 mouse strain C57BL/6 and the prototypical Th2 strain BALB/c. Although the age-related changes that occur may be rather subtle, they may be very relevant in conditions of disease and stress. Importantly, our data indicate that age and strain should be considered in concert in the selection of appropriate mouse models for immunological research.