title: Systemic histopathology of infant rats exposed to busulfan.
abstract: Busulfan is an antineoplastic bifunctional alkylating agent. We previously reported the busulfan-induced systemic histopathological changes in fetal rats and the sequence of brain lesions in fetal and infant rats. In the present study, in order to clarify the nature and sequence of busulfan-induced systemic histopathological changes in infant rats, 6-day-old male infant rats were subcutaneously administered 20 mg/kg of busulfan and histopathologically examined at 1, 2, 4, 7 and 14 days after treatment (DAT). As a result, histopathological changes characterized by pyknosis of component cells were observed in the heart, lungs, stomach, intestines, liver, kidneys, testes, epididymides, hematopoietic and lymphoid tissues, dorsal skin and femur as well as in the brain and eyes (data not shown in this paper). Such pyknosis transiently appeared until 7 DAT with prominence at 2 and/or 4 DAT in each tissue, except for the thymus, in which pyknosis peaked at 1 DAT. Most of the pyknotic nuclei were immunohistochemically positive for cleaved caspase-3, indicating that pyknotic cells were apoptotic. Different from the reports of fetal and adult rats, apoptosis was also found in cardiomyocytes and osteoblasts in infant rats.
authors.affiliation: Pathology Division, Gotemba Laboratories, BoZo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan.
authors.forename: Toko
authors.initials: T
authors.lastname: Ohira
authors.affiliation: Pathology Division, Gotemba Laboratories, BoZo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan.
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Saito
authors.affiliation: Pathology Division, Gotemba Laboratories, BoZo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ando
authors.affiliation: Pathology Division, Gotemba Laboratories, BoZo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Tamura
authors.affiliation: Pathology Division, Gotemba Laboratories, BoZo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hoshiya
keywords: apoptosis; busulfan; infant rat; systemic histopathology