Mise au point d'un modèle de leucémie aiguë lymphoblastique de type B, chimiquement induite chez le rat pour l'étude d'agents leucémogènes (application aux champs magnétiques de 50 Hz)

PARIS-BIUP (751062107) / SudocSudocFranceF

A new model of pre-B acute lymphoblastic leukemia chemically induced in rats.

OBJECTIVE: Although B acute lymphoblastic leukemia (B-ALL) is the most common leukemia among children, no chemically inducible model of this leukemia has yet been described in vivo. METHODS: Leukemia was chemically induced in male WKAH/Hkm rats by a nitrosourea derivative, N-butylnitrosourea (BNU), an alkylating agent, administered orally 5 days a week for 24 weeks. Development of leukemia was monitored by clinical observation, follow-up of blood parameters, and appearance of blast cells in peripheral blood samples. The phenotype of the leukemia was determined by cytological examination, cytochemical reactions, and by immunophenotyping of bone marrow cells using various markers. The feasibility of leukemia transplantation was investigated. Clonality and karyotype analyses were also performed. RESULTS: We observed the appearance of acute leukemia in 60% of the rats treated with BNU. Of these, 65% developed pre-B-ALL, which was serially transplantable to healthy WKAH/Hkm male rats. Karyotype analysis did not reveal clonal abnormalities. Clonality determined by immunoglobulin gene rearrangement sequencing disclosed that the pre-B-ALL were mostly oligoclonal. CONCLUSION: This new in vivo model of inducible pre-B-ALL might be useful for investigating the effects of co-initiating or promoting agents suspected to be involved in leukemia development, and for disclosing new molecular events leading to leukemogenic processes

Impairment of lymphocyte function in head-injured rats : Effects of standard and immune-enhancing diets for enteral nutrition

International audienceBACKGROUND: The metabolic response to head injury (HI) is characterized by a dysimmunity which may be a risk factor of a septic state. The use of immune enhancing diets (IEDs) could be a promising approach to improve immune functions. The aim of the study was to investigate the consequences of HI on lymphocyte function and to determine the effects of an enteral IED comparatively to a standard enteral nutrition. METHOD: A rat model of HI by fluid percussion was used. Twenty-five male Sprague-Dawley rats were randomized into 4 groups: rats receiving standard chow diet ad libitum (AL), rats sustaining HI and receiving standard chow diet and enteral saline (HI), rats receiving the enteral standard diet Sondalis HP (HIS), and rats receiving the IED Crucial (HIC). The two enteral diets were infused continuously during 4 days after the HI and were isocaloric, isonitrogenous and isovolumic. RESULTS: HI induced a thymus atrophy (HI vs. AL, P<0.05), and an impairment in lymphocyte CD25 receptor density responsiveness to stimulation. The IED blunted thymus atrophy and allowed to preserve the stimulation of blood and Peyer patches lymphocytes (HIC: Stimulated vs. Basal, P<0.05). CONCLUSION: IED seems more adapted for preserving lymphocyte function than standard diet in HI patients

Impairment of lymphocyte function in head-injured rats : Effects of standard and immune-enhancing diets for enteral nutrition

International audienceBACKGROUND: The metabolic response to head injury (HI) is characterized by a dysimmunity which may be a risk factor of a septic state. The use of immune enhancing diets (IEDs) could be a promising approach to improve immune functions. The aim of the study was to investigate the consequences of HI on lymphocyte function and to determine the effects of an enteral IED comparatively to a standard enteral nutrition. METHOD: A rat model of HI by fluid percussion was used. Twenty-five male Sprague-Dawley rats were randomized into 4 groups: rats receiving standard chow diet ad libitum (AL), rats sustaining HI and receiving standard chow diet and enteral saline (HI), rats receiving the enteral standard diet Sondalis HP (HIS), and rats receiving the IED Crucial (HIC). The two enteral diets were infused continuously during 4 days after the HI and were isocaloric, isonitrogenous and isovolumic. RESULTS: HI induced a thymus atrophy (HI vs. AL, P<0.05), and an impairment in lymphocyte CD25 receptor density responsiveness to stimulation. The IED blunted thymus atrophy and allowed to preserve the stimulation of blood and Peyer patches lymphocytes (HIC: Stimulated vs. Basal, P<0.05). CONCLUSION: IED seems more adapted for preserving lymphocyte function than standard diet in HI patients