Radiotherapy of abdominal and pelvic tumors almost inevitably injures the intestine by oxidative stress and causes inflammation. Regrettably, traditional radioprotective agents for irradiation (IR) induced intestinal injury suffer from challenges...

Radiation-induced intestinal injury (RIII) restricts the therapeutic efficacy of radiotherapy in abdominal or pelvic malignancies. Also, intestinal injury is a major cause of death following exposure to high doses of radiation in nuclear accidents. No safe and effective prophylactics or therapeutics for RIII are currently available. Here, we reported that the apigenin, a natural dietary flavone, prolonged the survival in c57 mice after lethal irradiation. Apigenin pretreatment brought about accelerated restoration of crypt-villus structure, including enhanced regenerated crypts, more differentiated epithelium cells, and increased villus length. In addition, intestinal crypt cells in the apigenin-treated group exhibited more proliferation and less apoptosis. Furthermore, apigenin increased the expression of Nrf2 and its downstream target gene HO-1, and decreased oxidative stress after irradiation. In conclusion, our findings demonstrate the radioprotective efficacy of apigenin. Apigenin has the potential to be used as a radioprotectant in cancer therapy and nuclear accidents.

Objective This study aimed to reveal the protective effect of hydrogen storage nanomaterial MgH2 on radiation-induced male fertility impairment. Methods The characterization of MgH2 were analyzed by scanning electron microscopy (SEM) and particle size analyzer. The safety of MgH2 were evaluated in vivo and in vitro. The radioprotective effect of MgH2 on the reproductive system were analyzed in mice, including sperm quality, genetic effect, spermatogenesis, and hormone secretion. ESR, flow cytometry and western blotting assay were used to reveal the underlying mechanisms. Results MgH2 had an irregular spherical morphology and a particle size of approximately 463.2 nm, and the content of Mg reached 71.46%. MgH2 was safe and nontoxic in mice and cells. After irradiation, MgH2 treatment significantly protected testicular structure, increased sperm density, improved sperm motility, reduced deformity rates, and reduced the genetic toxicity. Particularly, the sperm motility were consistent with those in MH mice and human semen samples. Furthermore, MgH2 treatment could maintain hormone secretion and testicular spermatogenesis, especially the generation of Sertoli cells, spermatogonia and round sperm cells. In vitro, MgH2 eliminated the [·OH], suppressed the irradiation-induced increase in ROS production, and effectively alleviated the increase in MDA contents. Moreover, MgH2 significantly ameliorated apoptosis in testes and cells and reversed the G2/M phase cell cycle arrest induced by irradiation. In addition, MgH2 inhibited the activation of radiation-induced inflammation and pyroptosis. Conclusion MgH2 improved irradiation-induced male fertility impairment by eliminating hydroxyl free radicals. Graphical abstract Mice fertility and function were evaluated with or without MgH2 treatment after 5 Gy irradiation. MgH2 had the ability of hydroxyl radicals scavenging and MDA suppressing in testicular tissue induced by irradiation. Further, MgH2 could participate in spermatogenesis and protect sperm development in three stages: the generation of Sertoli cells (Sox-9+), spermatogonia (Stra8+) and round sperm cells (Crem+). Moreover, MgH2 alleviated the decrease of testosterone secreted by interstitial cells after irradiation. In addition, MgH2 suppressed apoptosis, pyroptosis and inflammatory response and alleviated cell cycle arrest by mediating IR-induced ROS.

The testis is susceptible to ionizing radiation, and male infertility and sexual dysfunction are prevalent problems after whole-body or local radiation exposure. Currently, there is no approved agent for the prevention or treatment of radiation-induced testicular injury. Herein, we investigated the radioprotective effect of dimethyl sulfoxide (DMSO), an organosulfur compound that acts as a free radical scavenger, on testicular injury. Treatment of mice with a single dose of DMSO prior to 5 Gy irradiation restored sex hormones and attenuated the reduction in testis weight. Histological analyses revealed that DMSO alleviated the distorted architecture of seminiferous tubules and promoted seminiferous epithelium regeneration following irradiation. Moreover, DMSO provided quantitative and qualitative protection for sperm and preserved spermatogenesis and fertility in male mice. Mechanistically, DMSO treatment enhanced GFRα-1+ spermatogonial stem cell and c-Kit+ spermatogonial survival and regeneration after radiation. DMSO also alleviated radiation-induced oxidative stress and suppressed radiation-induced germ cell apoptosis in vivo and in vitro. Additionally, DMSO efficiently reduced DNA damage accumulation and induced the expression of phosph-BRCA1, BRCA1, and RAD51 proteins, indicating that DMSO facilitates DNA damage repair with a bias toward homologous recombination. In summary, our findings demonstrate the radioprotective efficacy of DMSO on the male reproductive system, which warrants further studies for future application in the preservation of male fertility during conventional radiotherapy and nuclear accidents.

Radiation-induced intestinal injury (RIII) occurs after high doses of radiation exposure. RIII restricts the therapeutic efficacy of radiotherapy in cancer and increases morbidity and mortality in nuclear disasters. Currently, there is no approved agent for the prevention or treatment of RIII. Here, we reported that the disulfiram, an FDA-approved alcohol deterrent, prolonged the survival in mice after lethal irradiation. Pretreatment with disulfiram inhibited proliferation within 24 h after irradiation, but improved crypt regeneration at 3.5 days post-irradiation. Mechanistically, disulfiram promoted Lgr5+ intestinal stem cells (ISCs) survival and maintained their ability to regenerate intestinal epithelium after radiation. Moreover, disulfiram suppresses DNA damage accumulation, thus inhibits aberrant mitosis after radiation. Unexpectedly, disulfiram treatment did not inhibit crypt cell apoptosis 4 h after radiation and the regeneration of crypts from PUMA-deficient mice after irradiation was also promoted by disulfiram. In conclusion, our findings demonstrate that disulfiram regulates the DNA damage response and survival of ISCs through affecting the cell cycle. Given its radioprotective efficacy and decades of application in humans, disulfiram is a promising candidate to prevent RIII in cancer therapy and nuclear accident.

Recently, Toll-like receptors (TLRs) have been extensively studied in radiation damage, but the inherent defects of high toxicity and low efficacy of most TLR ligands limit their further clinical transformation. CRX-527, as a TLR4 ligand, has rarely been reported to protect against radiation. We demonstrated that CRX-527 was safer than LPS at the same dose in vivo and had almost no toxic effect in vitro. Administration of CRX-527 improved the survival rate of total body irradiation (TBI) to 100% in wild-type mice but not in TLR4-/- mice. After TBI, hematopoietic system damage was significantly alleviated, and the recovery period was accelerated in CRX-527-treated mice. Moreover, CRX-527 induced differentiation of HSCs and the stimulation of CRX-527 significantly increased the proportion and number of LSK cells and promoted their differentiation into macrophages, activating immune defense. Furthermore, we proposed an immune defense role for hematopoietic differentiation in the protection against intestinal radiation damage, and confirmed that macrophages invaded the intestines through peripheral blood to protect them from radiation damage. Meanwhile, CRX-527 maintained intestinal function and homeostasis, promoted the regeneration of intestinal stem cells, and protected intestinal injury from lethal dose irradiation. Furthermore, After the use of mice, we found that CRX-527 had no significant protective effect on the hematopoietic and intestinal systems of irradiated TLR4-/- mice. in conclusion, CRX-527 induced differentiation of HSCs protecting the intestinal epithelium from radiation damage.