1
|
Rodríguez-Vázquez L, Martí J. An Animal Model for Assessing the Effects of Hydroxyurea Exposure Suggests That the Administration of This Agent to Pregnant Women and Young Infants May Not Be as Safe as We Thought. Int J Mol Sci 2018; 19:E3986. [PMID: 30544930 PMCID: PMC6320814 DOI: 10.3390/ijms19123986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/04/2018] [Accepted: 12/06/2018] [Indexed: 12/30/2022] Open
Abstract
The cytostatic agent hydroxyurea (HU) has proven to be beneficial for a variety of conditions in the disciplines of oncology, hematology, infectious disease and dermatology. It disrupts the S phase of the cell cycle by inhibiting the ribonucleotide reductase enzyme, thus blocking the transformation of ribonucleotides into deoxyribonucleotides, a rate limiting step in DNA synthesis. HU is listed as an essential medicine by the World Health Organization. Several studies have indicated that HU is well tolerated and safe in pregnant women and very young pediatric patients. To our knowledge, only a few controlled studies on the adverse effects of HU therapy have been done in humans. Despite this, the prevalence of central nervous system abnormalities, including ischemic lesions and stenosis have been reported. This review will summarize and present the effects of HU exposure on the prenatal and perinatal development of the rat cerebellar cortex and deep cerebellar nuclei neurons. Our results call for the necessity to better understand HU effects and define the administration of this drug to gestating women and young pediatric patients.
Collapse
Affiliation(s)
- Lucía Rodríguez-Vázquez
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
| | - Joaquín Martí
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
| |
Collapse
|
2
|
Hydroxyurea Exposure and Development of the Cerebellar External Granular Layer: Effects on Granule Cell Precursors, Bergmann Glial and Microglial Cells. Neurotox Res 2018; 35:387-400. [PMID: 30276718 DOI: 10.1007/s12640-018-9964-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/17/2018] [Accepted: 09/21/2018] [Indexed: 12/20/2022]
Abstract
The current paper presents a histological analysis of the cell death in the cerebellar external granular layer (EGL) following the treatment with a single dose (2 mg/g) of hydroxyurea (HU). The rats were examined at postnatal days (P) 5, 10, and 15, and sacrificed at appropriate times ranging from 6 to 48 h after treatment administration. Studies were done in each cortical lobe (anterior, central, posterior, and inferior). The quantification of several parameters, such as density of 5-bromo-2'-deoxyuridine, TUNEL, vimentin, and tomato lectin-stained cells, revealed that HU compromises the viability of EGL cells. Our results indicate that P10 is a time of high vulnerability to injury. We also show here that the anterior and central lobes are the cortical regions most susceptible to the action of the HU. Additionally, our data also indicate that from 6 to 24 h after HU-exposure is a time-window of high sensibility to this agent. On the other hand, our ultrastructural analysis confirmed that HU administration produces the activation of apoptotic cellular events in the EGL, resulting in a substantial number of dying cells. Different stages of apoptosis can be observed in all cortical lobes at all investigated postnatal ages and survival times. Moreover, we observed that dying neuroblasts were covered by laminar processes of Bergmann glia, and that these unipolar astrocytes presented cytological features of phagocytes engulfing apoptotic bodies and cell debris. The electron microscopy study also revealed the participation of ameboid microglial cells in the phagocytosis of apoptotic cells in the regions of the EGL with extensive cell death.
Collapse
|
3
|
Rodríguez-Vázquez L, Martí J. Effects of Hydroxyurea Exposure on the Rat Cerebellar Neuroepithelium: an Immunohistochemical and Electron Microscopic Study Along the Anteroposterior and Mediolateral Axes. Neurotox Res 2017; 32:671-682. [PMID: 28744838 DOI: 10.1007/s12640-017-9785-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/11/2017] [Accepted: 07/12/2017] [Indexed: 12/31/2022]
Abstract
We present a histological study of the cell death of cerebellar neuroepithelial neuroblasts following treatment with the cytotoxic agent hydroxyurea (HU) during the embryonic life. Pregnant rats were treated with a single dose of HU (300 mg/kg) at embryonic days 13, 14, or 15 of gestation, and their fetuses were studied from 5 to 35 h after treatment to elucidate the mechanisms of HU-induced fetotoxicity. Quantification of several parameters such as the density of pyknotic, mitotic, and PCNA-immunoreactive cells indicated that HU compromises the survival of the cerebellar neuroepithelium neuroblasts. On the other hand, our light and electron microscopic investigations during the course of prenatal development indicated that HU leads to two types of cell death: apoptosis and cells presenting cytoplasmic vacuolization, altered organelles, and a recognizable cell nucleus. Both modalities of cell death resulted in a substantial loss of cerebellar neuroepithelium cells. Current results suggest that HU exposure during gestation is toxic to the cerebellar neuroepithelium. Moreover, they allow to examine the mechanisms of HU-induced toxicity during the early development of the central nervous system. Our data also suggest that it is essential to avoid underestimating the adverse effects of HU when administered during early prenatal life.
Collapse
Affiliation(s)
- Lucía Rodríguez-Vázquez
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Joaquín Martí
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| |
Collapse
|
4
|
Martí J, Molina V, Santa-Cruz MC, Hervás JP. Developmental Injury to the Cerebellar Cortex Following Hydroxyurea Treatment in Early Postnatal Life: An Immunohistochemical and Electron Microscopic Study. Neurotox Res 2016; 31:187-203. [PMID: 27601242 DOI: 10.1007/s12640-016-9666-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/17/2016] [Accepted: 08/30/2016] [Indexed: 11/30/2022]
Abstract
Postnatal development of the cerebellar cortex was studied in rats administered with a single dose (2 mg/g) of the cytotoxic agent hydroxyurea (HU) on postnatal day (P) 9 and collected at appropriate times ranging from 6 h to 45 days. Quantification of several parameters such as the density of pyknotic, mitotic, BrdU-positive, and vimentin-stained cells revealed that HU compromises the survival of the external granular layer (EGL) cells. Moreover, vimentin immunocytochemistry revealed overexpression and thicker immunoreactive glial processes in HU-treated rats. On the other hand, we also show that HU leads to the activation of apoptotic cellular events, resulting in a substantial number of dying EGL cells, as revealed by TUNEL staining and at the electron microscope level. Additionally, we quantified several features of the cerebellar cortex of rats exposed to HU in early postnatal life and collected in adulthood. Data analysis indicated that the analyzed parameters were less pronounced in rats administered with this agent. Moreover, we observed several alterations in the cerebellar cortex cytoarchitecture of rats injected with HU. Anomalies included ectopic placement of Purkinje cells and abnormities in the dendritic arbor of these macroneurons. Ectopic granule cells were also found in the molecular layer. These findings provide a clue for investigating the mechanisms of HU-induced toxicity during the development of the central nervous system. Our results also suggest that it is essential to avoid underestimating the adverse effects of this hydroxylated analog of urea when administered during early postnatal life.
Collapse
Affiliation(s)
- Joaquín Martí
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, 08193, Barcelona, Spain.
| | - Vanesa Molina
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - M C Santa-Cruz
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - José P Hervás
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| |
Collapse
|
5
|
Martí J, Santa-Cruz MC, Serra R, Hervás JP. Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons. Neurotox Res 2016; 30:563-580. [PMID: 27401826 DOI: 10.1007/s12640-016-9649-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/28/2016] [Accepted: 06/29/2016] [Indexed: 12/17/2022]
Abstract
The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.
Collapse
Affiliation(s)
- Joaquín Martí
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
| | - M C Santa-Cruz
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Roger Serra
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - José P Hervás
- Unidad de Citología e Histología, Facultad de Biociencias, Universidad Autónoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| |
Collapse
|
6
|
Sun J, Sugiyama A, Inoue S, Takeuchi T, Furukawa S. Effect of methotrexate on neuroepithelium in the rat fetal brain. J Vet Med Sci 2013; 76:347-54. [PMID: 24200895 PMCID: PMC4013360 DOI: 10.1292/jvms.13-0457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pregnant rats were treated with 30 mg/kg of methotrexate (MTX) on gestation day
13, and fetal brains were examined histopathologically from 6 to 48 hr after the
treatment. In the telencephalon of the control group, there were few pyknotic
neuroepithelial cells throughout the experimental period. Six hr after MTX treatment,
several pyknotic neuroepithelial cells scattered throughout the telencephalic wall. At
12–36 hr, pyknotic neuroepithelial cells increased significantly and were diffusely
distributed throughout the telencephalic wall. Neuroepithelial cells were eliminated and
showed sparse cell density at 36 hr in the telencephalon. Almost all fetuses died at 48
hr. Most of the pyknotic neuroepithelial cells were positively stained by the TUNEL method
and positive for cleaved caspase-3. While mitotic and phospho-histone H3-positive
neuroepithelial cells were located along the ventricular layer of telencephalon in the
control group, they were rarely observed in the same region at 6–36 hr in the MTX-treated
group. MTX induced few pyknotic changes to neuroepithelial cells in the metencephalon,
compared to other parts of brain. The distribution of apoptotic neuroepithelial cells and
the time-course changes of the indices of apoptotic and mitotic neuroepithelial cells were
different from those of other DNA-damaging chemicals reported previously. The difference
may reflect the disparity in mechanisms of apoptosis and the inhibition of cell
proliferation in neuroepithelial cells induced by MTX. To our knowledge, this is the first
report demonstrating histopathological findings of fetal brain damage induced by MTX.
Collapse
Affiliation(s)
- Jing Sun
- Courses of Veterinary Laboratory Medicine, School of Veterinary Medicine, Faculty of Agriculture, Tottori University, 4-101 Koyama-cho Minami, Tottori, Tottori 680-8553, Japan
| | | | | | | | | |
Collapse
|
7
|
Yamaguchi T, Kanemitsu H, Yamamoto S, Komatsu M, Uemura H, Tamura K, Shirai T. N,N'-Bis(2-chloroethyl)-N-nitrosourea (BCNU)-induced Apoptosis of Neural Progenitor Cells in the Developing Fetal Rat Brain. J Toxicol Pathol 2010; 23:25-30. [PMID: 22272008 PMCID: PMC3234648 DOI: 10.1293/tox.23.25] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 10/13/2009] [Indexed: 11/23/2022] Open
Abstract
N,N’-bis(2-chloroethyl)-N-nitrosourea
(BCNU) is one of the major drugs used in chemotherapy against malignant
gliomas due to its effects, such as induction of bifunctional alkylation of
DNA and formation of interstrand DNA cross-linkages, and induces cortical
malformations in the fetal and neonatal rat brain. In this study, pregnant
rats were treated with 7.5 mg/kg of BCNU on gestational day 13 (GD 13), and
their fetuses were collected from 12 to 72 hours after BCNU treatment in
order to examine the timecourses of morphological and immunohistochemical
changes in neural progenitor cells in the developing brain. The number of
pyknotic cells in the telencephalon peaked at 24 h and then gradually
decreased until 72 h. The majority of these pyknotic cells were positive
for cleaved caspase-3, a key executioner of apoptosis. The pyknotic cells
showed the ultrastructural characteristics of apoptosis. The number of
p53-positive cells began to increase prior to the appearance of apoptotic
cells and p21-positive cells. The number of phosphorylated-histone
H3-positive cells (mitotic cells) decreased from 24 to 36 h. The number of
Iba1-positive cells (microglial cells) in the telencephalon increased from
12 to 48 h. These results suggest that BCNU induces p53-dependent apoptosis
and reduces proliferative activity, resulting in reduction of the weight of
the telencephalon and the thickness of the telencephalic wall in the fetal
brain. This study will help to clarify the mechanisms of BCNU-induced fetal
brain toxicity.
Collapse
Affiliation(s)
- Tsuyoshi Yamaguchi
- Bozo Research Center Inc., Gotemba-shi, Shizuoka 412-0039,
Japan
- Department of Experimental Pathology and Tumor Biology,
Nagoya City University Graduate School of Medical Sciences, Nagoya
467-8601, Japan
| | | | - Satoshi Yamamoto
- Bozo Research Center Inc., Gotemba-shi, Shizuoka 412-0039,
Japan
| | - Masahiko Komatsu
- Bozo Research Center Inc., Gotemba-shi, Shizuoka 412-0039,
Japan
| | - Hiroyuki Uemura
- Bozo Research Center Inc., Gotemba-shi, Shizuoka 412-0039,
Japan
| | - Kazutoshi Tamura
- Bozo Research Center Inc., Gotemba-shi, Shizuoka 412-0039,
Japan
| | - Tomoyuki Shirai
- Department of Experimental Pathology and Tumor Biology,
Nagoya City University Graduate School of Medical Sciences, Nagoya
467-8601, Japan
| |
Collapse
|