Sanguisorba parviflora (Maxim.) Takeda alleviates cyclophosphamide-induced leukopenia by regulating haematopoietic cell-specific protein 1-associated protein X-1 gene expression.

Abstract

We have previously shown that the saponins of Sanguisorba parviflora (Maxim.) Takeda (Sp. T) relieved cyclophosphamide-induced myelosuppression in leukopenic mice. Haematopoietic cell-specific protein 1-associated protein X-1 (HAX-1) participated in the survival of neutrophils through the regulation of mitochondrial function. The aim of the present study was to comprehensively identify the role of HAX-1 in the mechanism of leukopenia alleviation by Sp.T. HAX-1gene and protein expression levels in peripheral blood neutrophils were examined using real-time quantitative reverse transcription-polymerase chain reaction, western blot and immunohistochemical assays. Neutrophil apoptosis was measured using flow cytometry. Mitochondrial function was determined via assessments of the reactive oxygen species (ROS) generation and mitochondrial membrane potential (ΔΨm) integrity levels. The HAX-1gene expression level in the peripheral blood neutrophils was significantly lower in patients with leukopenia than in healthy donors. The saponins of Sp.T induced HAX-1 expression and promoted myeloid progenitor cell (mEB8-ER cell) viability. HAX-1 overexpression reduced the production of ROS and maintained ΔΨm integrity. Cyclophosphamide-induced mitochondrial dysfunction and apoptosis could be abrogated by treatment with Sp.T or metformin. Our data suggest a mechanism through which Sp.T protects against chemotherapy-induced leukopenia by regulating HAX-1gene expression in a mitochondrial-dependent manner.