Effect of preventive administration of probiotics on bone marrow myeloid cells after cyclophosphamide treatment

VILLENA JULIO; SALVA SUSANA; HERRERA MATÍAS; BARBIERI NATALIA; PACHECO VICTORIA; ALVAREZ SUSANA

San Miguel de Tucumán. Tucumán. Argentina

Simposio; III International Symposium on Lactic Acid Bacteria. II Argentinean LAB Net Meeting; 2009

CERELA-CONICET

The aim of this work was to determine the daily changes in mature granulocytes and progenitor cells in the post-chemotherapy blood and bone marrow (BM), and to determine the effect of different probiotic preventive treatments on blood count recovery as well as progenitor and stem cell mobilization. Different groups of Swiss-albino mice were fed Lactobacillus casei CRL 431 (Lc431, 109 cells/day/mouse) or Lactobacillus rhamnosus CRL 1506 (Lr06, 108 cells/day/mouse) for 2 or 5 consecutive days respectively. After each treatment, these mice and untreated controls (CG) received an intraperitoneal injection of cyclophosphamide (Cph) (150 mg/Kg). Mice were sacrificed at day 0 (before Cph administration) and in different time points after chemotherapy (during 15 days). We analyzed in blood and bone marrow: a) the total and differential cell counts, b) peroxidase activity and, c) Gr-1 and CD34 expression with flow cytometry. The administration of Cph induced a severe leukopenia with neutropenia. Lc431 and Lr06 groups showed a less severe neutropenia and an early recovery of this parameter, with respect to CG mice. In the BM, the Cph induced a decrease in the total number of cells, affecting both the mitotic and post-mitotic pool cells. Treatments with probiotics induced a significant increase in the number of cells in the mitotic pool and a less severe decrease in the total number of cells with respect to CG group. Probiotic treatments did not induce changes in blood Gr-1hi cells (mature neutrophils) before the administration of Cph. However, both Gr-1hi and Gr-1low (blasts and myelocytes) cells in BM were significantly increased in mice treated with Lc431 or Lr06 with respect to the CG group (day 0). In all experimental groups, the administration of Cph induced a decrease of blood and BM Gr-1hi and Gr-1low cells, which reached its minimum value on day 3 post-chemotherapy. However, the groups treated with probiotics showed numbers of Gr-1low cells higher than the CG group during all the studied period. We found that approximately 6% (3.6 106cell/femur) of nucleated BM cells from untreated mice were committed early and intermediate progenitors (CD34+ cells). Moreover, the majority of CD34+ cells were also Gr-1low positive, which represent immature myeloid progenitors. Both CD34+ and double-positive CD34/Gr-1 cells in BM were significantly increased by probiotic treatments (day 0). Administration of Cph reduced the number of BM CD34+ and CD34/Gr-1 cells in all groups; however Lc431 and Lr06 groups showed higher numbers of these cells with respect to the CG mice. Results showed that probiotic treatment is able to increase immature myeloid progenitors in the bone marrow. The higher numbers of these cells would allow an early recovery of myeloid cells in blood and bone marrow after the administration of Cph. To our knowledge, we demonstrated for the first time, the influence of probiotic preventive treatment on myeloid cell recovery after chemotherapy.