Clinical Pathology Standard Parameters in Nude Rats

Clinical Pathology Standard Parameters in Nude Rats: De Novo Generation of Reference Intervals

Anes Bendrimia, Alexandre Bidaut, Vitalis Jacquemet, Myriam Defontis

Introduction: Long term pharmacology and safety evaluation of innovative human-derived cell therapy products require the use of immunocompromised animals to avoid immune-mediated destruction of injected human-derived cells. Athymic Nude (RH-FoxN1rnu) rats represent an interesting alternative to broadly used Nude mice, particularly when implantation surgery is required and animals of larger size are preferred. Clinical pathology data obtained from this rat strain remain sparse in the literature.

Materials and methods: We sampled 34 untreated Nude male (N=16) and female (N=18) rats and analyzed a standard panel of hematology (Sysmex XN-1000V), biochemistry (Pentra C400) and coagulation (STA-Satellite Max) parameters routinely used in toxicology studies. Blood smears were prepared and examined. Data were qualitatively reviewed and compared with data obtained from conventional rat strains.

Results: Whilst most biochemistry and coagulation parameters were overall unchanged, in hematology, white blood cell differential counts strongly differed from those recorded in other rat strains.

Conclusions: Full clinical pathology profiles of nude rats including blood smear examination enabled to characterize the Nude rat strain and to produce first reference intervals. Specific hematology changes were observed and consistent with the T-cell deficient phenotype of this rat strain. Those results should be taken into consideration when interpreting study results.