Hematological profile of untreated or ionizing radiation-exposed cyclooxygenase-2-deficient mice

Hematological reference values and animal welfare parameters of BALB/C-FMABC (Mus musculus) inoculated with Ehrlich tumor kept in the vivarium at ABC Medical School

BACKGROUND

Biochemical and hematological parameters are important tools for assessing the physiological profile of vital organs, and can be recorded to create reference values used for clinical diagnosis of diseases. Many research laboratories lack the means to establish their own set of reference parameters for use in their research, and while there are articles in the literature that discuss laboratory parameters for healthy BALB/c mice, few studies address the evaluation of these parameters in pathological situations, such as in mice inoculated with Ehrlich tumor.

METHOD

BALB/c-FMABC mice previously inoculated with Ehrlich tumor were maintained under appropriate conditions. Blood samples were taken for analysis of hematological parameters using automated and semi-automated equipment to create a set of the animal welfare parameters for evaluation.

RESULT

Results were obtained for all the hematological parameters for all groups analyzed. These showed: statistically significant differences between the initial and final tumor weight; comparable initial tumour volume and weight; an increase in leukocytes in the 7-day group with a characteristic predominance of lymphocytes and neutrophils; statistically significant changes in RDW in the 21-day group and in the welfare parameters in the 28-day group.

CONCLUSION

The study successfully defined and established reference values for hematological and welfare parameters for all groups analyzed.

Brief Story on Prostaglandins, Inhibitors of their Synthesis, Hematopoiesis, and Acute Radiation Syndrome

Prostaglandins and inhibitors of their synthesis (cyclooxygenase (COX) inhibitors, non-steroidal anti-inflammatory drugs) were shown to play a significant role in the regulation of hematopoiesis. Partly due to their hematopoiesis-modulating effects, both prostaglandins and COX inhibitors were reported to act positively in radiation-exposed mammalian organisms at various pre- and post-irradiation therapeutical settings. Experimental efforts were targeted at finding pharmacological procedures leading to optimization of therapeutical outcomes by minimizing undesirable side effects of the treatments. Progress in these efforts was obtained after discovery of selective inhibitors of inducible selective cyclooxygenase-2 (COX-2) inhibitors. Recent studies have been able to suggest the possibility to find combined therapeutical approaches utilizing joint administration of prostaglandins and inhibitors of their synthesis at optimized timing and dosing of the drugs which could be incorporated into the therapy of patients with acute radiation syndrome.

Impaired post-irradiation survival of cyclooxygenase-2-deficient mice

We investigated and evaluated post-irradiation survival in cyclooxygenase-2-deficient (COX-2 KO) mice. Thirty-day survival following exposure of COX-2 KO mice to a lethal dose of 8.5 Gy of gamma-rays was observed to be statistically significantly lower in both males and females, as well as when the sexes were merged, in comparisons with their wild-type counterparts. These findings were related to the previous observations concerning the detrimental influence of the COX-2 genetic disruption on hematopoiesis in sublethally irradiated mice. Deteriorated post-irradiation survival of COX-2 KO mice confirmed the previously anticipated conclusion regarding negative influence of the antiinflammatory action of COX-2 deficiency under the conditions of exposure of the animals to ionizing radiation.

Cyclooxygenase‑2‑mediated upregulation of heme oxygenase 1 mitigates the toxicity of deuterium‑tritium fusion radiation

Utilizing the energy released from the nuclear fusion of deuterium with tritium (D-T) may be an important method of supplying energy in the future. The ionizing radiation emitted from nuclear fusion is a potential health risk to humans, including scientists who are currently performing nuclear fusion experiments and the employees of fusion nuclear plants, in the future. However, there have been few reports on the biological effects of fusion radiation. In the present study, using the High Intensity D-T Fusion Neutron Generator, the DNA damage and its regulation in normal human fibroblasts exposed to fusion radiation were investigated. Heme oxygenase 1 (HO-1), which is reported to induce anti-inflammatory activity, was upregulated in the irradiated cells. Pretreatment with the HO-1 inhibitor, protoporphyrin IX zinc (II), exacerbated double strand break formation following exposure to fusion radiation. The expression of cyclooxygenase-2 (COX-2) contributed to the upregulation of HO-1, as demonstrated by the result that its inhibitor, NS-398, inhibited the induction of HO-1 in irradiated cells. It was further clarified that the ataxia telangiectasia mutated DNA damage response was activated and it stimulated the phosphorylation of p38 mitogen-activated protein kinase, which was responsible for the upregulation of COX-2 and HO-1. These results provide novel information on fusion radiation-induced biological effects and potential targets for decreasing the associated health risks.