Comparative study of myelopoiesis immunoenhancers obtained from different lactobacillus strains

Abstract

Myelosuppression is the major dose-limiting toxicity of systemic cancer chemotherapy. Thereare many attempts to find new strategies that reduce myelosuppression. Hence, themyelopotentianting potential of L. rhamnosus CRL1505 and its cell wall (CW1505), wasevaluated in cyclophosphamide-immunosuppressed mice. Moreover, we compared thisproperty with the non-probiotic L. rhamnosus CRL534 and the other probiotic L. plantarumCRL1506, and their cell walls (CW1506 and CW534 respectively). Different group of Swiss micewere orally treated with three strains (108UFC/mouse/day) or their cell walls (8μg/mice/day)during 10 consecutive days. On day 6, treated and untreated control mice received anintraperitoneal dose of cyclophosphamide (150 mg/kg). Cyclophosphamide impaired steadystatemyelopoiesis. CW1505 and CRL1505 strain promoted a significant increase of bonemarrow (BM) LSK cells (Lin-Ckit+SCA1+) and myeloid multipotent precursors (MMP: Lin+CD34+)and mitotic pool cells with respect to untreated mice (p<0.05). Besides, CW1505 and CRL1505strain were the only treatments able to reduce the BM cells undergoing apoptosis at 5 dayspost-cyclophosphamide. Consequently, CW1505 minimized leukopenia promoting a fasterrecovery of BM mature myeloid cells (Ly6G+Gr-1+Ly6C-), blood leukocytes and neutrophils.These parameters were similar to the untreated control group. The principal componentanalysis explained the variability of 82.9% of the data, separating L. rhamnosus CRL1505 andCW1505 treatments in a different profile of the other groups. This behavior is explained by thenumber of LSK cells, MMP, BM and blood leukocytes and neutrophils. In conclusion, themyelopotentiating effect of CW1505 is a strain specific property. CW1505 could be considered apotential adjuvant to revert chemotherapy-induced leukopenia.