Effects of lactoferrin on X-ray-induced intestinal injury in Balb/C mice

Intestinal injury is common after radiotherapy. We aim to investigate the effects of lactoferrin (Lf) on X-ray-induced intestinal injury in Balb/C mice.

In assessing animal survival, a total of 40 animals were assigned randomly to 8Gy group, 2 mg Lf+8Gy group, 4 mg Lf+8Gy group, and 6 mg Lf+8Gy group. Mice were administered with Lf intraperitoneally and exposed to single whole-body X-ray irradiation. Lf administration lasted for 3 days. Survival rate was compared among groups. For the observation of intestinal injury, a total of 60 animals were divided randomly into control group, 5Gy group, 2 mg Lf+5Gy group, and 4 mg Lf+5Gy group. Lf was administered once a day. Five mice in each group were randomly sacrificed at days 1, 3, and 9 after irradiation. Fasting blood was used to determine serum levels of pro-inflammatory cytokines IL-6 and TNF-α, and anti-inflammatorycytokine IL-10. Intestinal tissues were collected to examine histological changes and determine the protein expression levels of NF-κB, IKKα and IKKβ.

Mean survival time was 4.30 ± 1.34, 4.20 ± 0.71, 5.75 ± 2.44 and 6.70 ± 2.54 days in four groups, respectively, with significantly longer duration in 6 mg Lf+8Gy group than in the 8Gy group. Survival rate was significantly higher in 4 mg Lf+8Gy group and 6 mg Lf+8Gy group, compared with the 8Gy group. For intestinal histology, the radiation-induced injury was considerably improved in the 2 mg Lf+5Gy and 4 mg Lf+5Gy groups. Villus length and its ratio to crypt depth significantly increased in the two Lf intervention groups. Compared with 5Gy group, serum levels of IL-6 and TNF-α significantly decreased in the two Lf intervention groups at days 3 and 9. Furthermore, Lf significantly reduced the radiation-induced expression of IKKα/β and NF-κB at day 3 and/or day 9.

Lf extended the survival time of radiated mice and improved intestinal injury by decreasing inflammatory cytokines and downregulating NF-κB expression.