目的 連續(xù)7 d重復(fù)給予C57BL/6J小鼠N-亞硝基二甲胺（NDMA）和N-亞硝基二乙胺（NDEA），觀察至首次給藥后28 d，評價兩者主要毒性靶器官及遺傳毒性風(fēng)險。方法 分設(shè)溶媒對照組（0.5%羧甲基纖維素鈉），受試物組（分別給予0.75、1.50、3.00 mg·kg^-1 NDMA或3.25、7.50、15.00 mg·kg^-1 NDEA）和陽性對照組（200 mg·kg^-1甲磺酸乙酯、40 mg·kg^-1N-乙基-N-亞硝基脲）。溶媒對照組和受試物組連續(xù)7 d每天ig給藥1次，陽性對照組連續(xù)3 d每天ig給藥1次。末次給藥后開展小鼠肝、腎和外周血彗星試驗，計算每只動物的肝、腎和血細(xì)胞尾DNA百分含量（% Tail DNA）和尾距（tail moment）平均值。觀察結(jié)束后（D28）開展小鼠磷脂酰肌醇聚糖A類（Pig-a）基因突變試驗，計算網(wǎng)織紅細(xì)胞（RET^CD24-）和總紅細(xì)胞（RBC^CD24-）的突變率。并在末次給藥和恢復(fù)期結(jié)束后，試劑盒法檢測小鼠肝、腎和肺的8-羥基脫氧鳥苷（8-OHdG）水平、實時熒光定量PCR（qRT-PCR）法檢測DNA損傷基因（ATM、gH2AX、Nbn、Prkdc、Trp）和肝藥酶基因（CYP2E1、CYP2A6）。結(jié)果 NDMA劑量為3 mg·kg^-1時，動物全部死亡，自連續(xù)給藥4 d后，NDEA 15 mg·kg^-1組小鼠體質(zhì)量與溶媒對照組相比顯著性降低（P＜0.001）；且NDMA和NDEA組與溶媒對照組在臟器系數(shù)、血液生化指標(biāo)、組織病理學(xué)等方面存在顯著差異（P＜0.05、0.01、0.001），提示NDMA和NDEA對肝臟和腎臟存在一定毒性；NDMA和NDEA組小鼠肝、腎彗星試驗結(jié)果均為陽性，Pig-a基因突變試驗中NDEA高劑量組RET^CD24-結(jié)果為陽性；與溶媒對照組比較，NDMA和NDEA組小鼠肝、腎和肺中8-OHdG含量顯著升高（P＜0.05、0.001），DNA損傷和肝藥酶基因表達(dá)也存在顯著差異（P＜0.05、0.001）。結(jié)論 NDMA分別在1.5 mg·kg^-1劑量條件下產(chǎn)生肝臟毒性，0.75、1.50 mg·kg^-1劑量條件下使小鼠肝、腎細(xì)胞產(chǎn)生致突變性和肝、腎DNA損傷；NDEA可在15 mg·kg^-1劑量條件下產(chǎn)生肝臟毒性，并導(dǎo)致肝、腎細(xì)胞產(chǎn)生致突變性和DNA損傷；8-OHdG和DNA損傷基因等指標(biāo)檢測結(jié)果與NDMA和NDEA遺傳毒性結(jié)果具有一定關(guān)聯(lián)性。

Objectives Repeated administration of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) in C57BL/ 6J mice for seven consecutive days was observed until 28 days after the first administration, and the main toxic target organs and genotoxic risk of both were evaluated. Methods A solvent control group (0.5% sodium carboxymethyl cellulose), a test group (0.75, 1.50, 3.00 mg·kg^-1 NDMA or 3.25, 7.50, 15.00 mg·kg^-1 NDEA, respectively) and a positive control group (200 mg·kg^-1 ethyl mesylate; 40 mg·kg^-1 N-ethyl-n-nitrosourea). The solvent control group and the test group were given ig once a day for seven consecutive days, and the positive control group was given ig once a day for three consecutive days. Comet tests in mouse liver, kidney, and peripheral blood were performed after the final dose, and the average percentage of Tail DNA and Tail Moment in liver, kidney, and blood cells of each animal were calculated. After observation (D28), mouse Pig-a gene mutation test was carried out to calculate the mutation rate of reticulocyte (RET^CD24-) and total erythrocyte (RBC^CD24-). The expression of 8-hydroxydeoxyguanosine (8-OHdG), DNA damage genes (ATM, gH2AX, Nbn, Prkdc, Trp) and liver drug enzyme genes (CYP2E1, CYP2A6) in liver, kidney and lung were studied after the final administration and recovery period. Results When the dose of NDMA was 3 mg·kg^-1 all the animals died. After continuous administration for four days, the body weight of mice in the NDEA 15 mg·kg^-1 group significantly decreased compared to the solvent control group (P＜0.001). There were differences in organ coefficient, blood biochemical index and histopathology between NDMA and NDEA and the solvent control group (P＜0.05, 0.01, and 0.001), suggesting that NDMA and NDEA had certain toxicity to liver and kidney. The results of comet test in liver and kidney of NDMA and NDEA mice were positive, and RET^CD24- in Pig-a gene mutation test of high-dose NDEA group was positive. The content of 8-OHdG in liver, kidney and lung of NDMA and NDEA groups was significantly increased (P＜0.05, 0.001), and there were significant differences in DNA damage and liver drug enzyme gene expression (P＜0.05, 0.001). Conclusion NDMA produced hepatotoxicity at a dose of 1.5 mg·kg^-1, and mutagenic and DNA damage in liver and kidney cells at a dose of 0.75 mg·kg^-1, respectively. NDEA can produce hepatotoxicity at a dose of 15 mg·kg^-1, and lead to mutagen and DNA damage in liver and kidney cells. It has been proved that the results of 8- OHdG and DNA damage genes are related to the genotoxicity results of NDMA and NDEA.

國家十三五“重大新藥創(chuàng)制”專項（2018ZX09201017）