Feature on Erythropoiesis in Dietary Restricted Rats

Abstract

ABSTRACT. We attempted to characterize the influence of undernutrition on erythropoiesis in toxicity studies. Male rats were divided into the following 5 groups: dietary restriction groups in which feeding was restricted by 33% or 66% for 14 days (R33 and R66); phlebotomy groups in which 1% or 4% of total blood volume was removed by serial phlebotomy for 14 days (PB01 and PB04); and a nontreated group (NT). Toxicological parameters such as hematology and blood chemistry were evaluated. The body weight gains in the R33 and phlebotomy groups (PB01 and PB04) were similar and were less than that observed in the NT group. Decreases in peripheral blood reticulocytes, bone marrow erythroids and the unsaturated iron binding capacity (UIBC) were observed as changes that suppressed erythropoiesis in the R33 and R66 groups. However, increases in reticulocytes and UIBC were observed as opposite changes in the phlebotomy groups. In addition, an increase in the blood urea nitrogen level and a decrease in the serum alkaline phosphatase level were observed as changes reflecting poor nutrition in the phlebotomy groups. Decreased reticulocytes which are related to poor nutrition were not observed. However, increases in those cells as reflected by a loss of blood were observed in the phlebotomy groups. Even if undernutrition suppresses erythropoiesis, the ability of erythropoiesis to respond to a demand appears to be retained. In repeated dose toxicity studies, decreased food consumption is often observed in the drug administration groups. Our study results provide useful information for hematological evaluations in toxicity studies.

Toxicity of humidifier disinfectant polyhexamethylene guanidine hydrochloride by two-week whole body-inhalation exposure in rats

“…RBC, HCT, HGB, MCHC, MCH, MCV, RET, RET %, and PLT changed significantly in males and females exposed to 1, 5, and 25 mg/m 3 . This may be attributed to decreased hematopoiesis caused by anorexia 18,19 . In addition, MON%, NEU, NEU%, and LYM% changed significantly in males and females exposed to 5 and 25 mg/m 3 .…”

Differences in hematologic variables in rats of the same strain but different origin

“…External factors, such as exercise and environment, can also influence cell populations in peripheral blood . Finally, many studies have shown that nutrition has an effect on hematologic variables in rats . In people, geographic origin can influence reference intervals, and separate reference intervals are often established for different human subpopulations …”

“…Aging also has an influence on WBC and lymphocyte counts with young rats having lower values . Furthermore, restricted food intake may cause a leukopenia and lymphopenia …”

“…Age‐dependent changes have been reported for RBC counts, which increase in older rats, whereas MCV, MCH, and reticulocyte counts decrease with age . Reduced food intake may be a reason for increasing RBC counts, HGB concentration, HCT, and MCHC as food restriction may influence a rat's drinking behavior, inducing hemoconcentration …”

Assessment of respiratory and systemic toxicity of Benzalkonium chloride following a 14-day inhalation study in rats

“…The changes in the MCV, reticulocyte count and ratio, PLT count, APTT, and PT in the male T3 group rats; the reticulocyte count and ratio, PLT count, and PT in the male rats exposed to T2 group rats; the reticulocyte count and ratio, APTT, and PT in the female T3 group rats; and the PT in the female T2 group rats were observed. These changes can be attributed to the reduction in hematopoietic function due to the decrease in feed intake and the subsequent weight loss [28,29]. The changes in the number of lymphocytes observed in the T3 group rats were inferred to be due to nutritional deficiency or stress due to weight loss [30].…”