Objective  To investigate the effect of tritium water on the intestinal absorption function of mice.

Methods  Ten BALB/c strain male mice with specific pathogen free were randomly divided into a control (n=5) and an experimental group (n=5) through simple random sampling. The experimental group mice were intraperitoneally injected with a single dose of tritium water (2.85×10⁵ Bq/g). Those in the control group received intraperitoneal injection with an equivalent amount of phosphate-buffered solution. Mice in both groups were normally raised in a radioactive experimental animal room with a constant temperature of 26℃ and a constant humidity of 50% for 7 days. Mice were anesthetized with 400 mg/kg tribromoethanol and euthanized, and jejunal tissue samples were collected. Transmission electron microscopy was performed to observe changes in the ultrastructure of the mouse intestine. Terminal-deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay was conducted to detect cell apoptosis. Quantitative real-time polymerase chain reaction was used to measure the expressions of genes related to nutrient transporters in mice intestinal epithelial cells. Triglycerides (TG) and total cholesterol (T-CHO) were measured using their respective test kits to determine their content in the mouse intestine to further verify the effect of tritium water on intestinal absorption function. Comparisons between the two groups were attained through t-test (for equal variance).

Results  Compared with the control group, no significant changes were observed in the ultrastructure of jejunum cells, nuclei, mitochondria, or intestinal villi of the experimental group. No apoptosis was detected in the jejunum cells of the experimental group. The expressions of SLC2A5 and FABP6 genes on the intestinal epithelial cell membrane of the experimental group mice were significantly increased (2^−∆∆CT: (2.7±2.5) vs. (1.0±0.1), 2^−∆∆CT: (27.5±0.3) vs. (1.0±0.1), t=8.63, 252.40; P=0.001, <0.001), and those of genes, such as SLC5A1, SLC38A1, SLC38A2, VAQUA POR2N1, VAQUA POR2N2, SLC26A6, SLC44A1, RBP2, SLC23A1, SLC20A1, SLC25A3, APOA1, SLC25A36, SLC35A3, SLC37A4, and SLC39A3 were significantly decreased, and the differences were statistically significant (t=4.33–2 386.00, all P<0.05). The contents of T-CHO and TG in the intestinal tissues were significantly reduced ((0.060±0.120) mmol/g vs. (1.050±1.170) mmol/g, (0.030±0.005) mmol/g vs. (0.200±0.035) mmol/g, t=3.18, 8.57; P=0.034, 0.001).

Conclusion  A certain dose of tritium water inhibits the intestinal absorption function of mice and decreases the expression levels of genes related to nutrient transporters in the intestinal epithelial cells but does not induce apoptosis in intestinal cells nor cause changes in organelle morphology.