Background Data for General Toxicology Parameters in RccHanTM:WIST Rats at 8, 10, 19 and 32 Weeks of Age

Abstract

Recently, RccHanTM:WIST (Wistar Hannover) rats were introduced to toxicity studies in Japan. The present study was performed to obtain control data for general toxicological parameters as an aid for interpretation of results in toxicity studies using this strain of rats. Four test groups comprising of 25 male and 25 female RccHanTM:WIST rats were housed for 2, 4, 13 or 26 weeks from 6 weeks of age and observed and examined for clinical observation, body weight, food consumption, urinalysis, hematology, blood chemistry, organ weight, necropsy and/or histopathology. Ophthalmological examination was not conducted in this study, and the data in this report were obtained from an ongoing 104-week background study in RccHanTM:WIST rats. These data were compared with the historical control data of CD(SD) (Sprague-Dawley) and/or F344 (Fischer) rats. The body weights of RccHanTM:WIST rats were lower than those of CD(SD) rats and higher than those of F344 rats. The ophthalmological examination revealed a greater incidence of focal corneal opacity. Histopathology revealed focal mineralization of the cornea and Berlin blue-positive pigmentation in the epididymal interstitium as well as hepatocytes. Other than the above, some minor differences were found in urinalysis, hematology, blood chemistry and organ weights as compared with CD(SD) rats.

Change Trends of Organ Weight Background Data in Sprague Dawley Rats at Different Ages

“…During the process of nonclinical drug safety evaluation, the toxicity of some drugs may only result in animal organ weight or organ coefficient changes. Therefore, organ background data is particularly important because they not only can be used to determine whether treatment group animal organ weights are in the range of background data or not but also provide an important reference to provide to pathologists for gross anatomy and microscopic examinations 2 . In many institutes including our laboratory in China, CD(SD) (Sprague-Dawley) rats are used predominantly as experimental models in toxicity studies, and they have been used as traditional animal models for assessing carcinogenic potential of various kinds of compounds 3 .…”

Corneal Mineralization in Wistar Hannover Rats

“…Through this work, we realized that there were high incidences of corneal mineralization in Wistar Hannover rats. A greater incidence of corneal mineralization in Wistar Hannover rats as one of the histological characteristics of this strain was reported 11 , but to our knowledge, there are no reports concerning histological details of corneal mineralization in this strain. In this study, we demonstrated the histopathological and ultrastructural characteristics of corneal mineralization in Wistar Hannover rats, as well as its incidence.…”

Integrated analysis of toxicity data of two pharmaceutical immunosuppressants and two environmental pollutants with immunomodulating properties to improve the understanding of side effects—A toxicopathologist׳s view

“…In large sample sizes, 'spontaneously' occurring outliers are expected. Collection of historical data including spontaneous incidences of outliers within laboratory specific data is routinely done in toxicology (examples: Hayakawa et al, 2013;Lee et al, 2012;Okamura et al, 2011). In addition, the incidence of outliers in clinical chemistry or hematology and unusual histopathologic findings in controls is surveyed in larger databases.…”