Myelosuppression is the most common complication of chemotherapy. Decline of self-renewal capacity and stress-induced premature senescence (SIPS) of hematopoietic stem cells (HSCs) induced by chemotherapeutic agents may be the cause of long-term myelosuppression after chemotherapy. Whether the mechanism of SIPS of hematopoietic cells relates to chemotherapeutic injury occurred in hematopoietic microenvironment (HM) is still not well elucidated. This study explored the protective effect of Angelica sinensis polysaccharide (ASP), an acetone extract polysaccharide found as the major effective ingredients of a traditional Chinese medicinal herb named Chinese Angelica (Dong Quai), on oxidative damage of homo sapiens bone marrow/stroma cell line (HS-5) caused by 5-fluorouracil (5-FU), and the effect of ASP relieving oxidative stress in HM on SIPS of hematopoietic cells. Tumor-suppressive doses of 5-FU inhibited the growth of HS-5 in a dose-dependent and time-dependent manner. 5-FU induced HS-5 apoptosis and also accumulated cellular hallmarks of senescence including cell cycle arrest and typical senescence-associated β-galactosidase positive staining. The intracellular reactive oxygen species (ROS) was increased in 5-FU treated HS-5 cells and coinstantaneous with attenuated antioxidant capacity marked by superoxide dismutase and glutathione peroxidase. Oxidative stress initiated DNA damage indicated by increased γH2AX and 8-OHdG. Oxidative damage of HS-5 cells resulted in declined hematopoietic stimulating factors including stem cell factor (SCF), stromal cell-derived factor (SDF), and granulocyte-macrophage colony-stimulating factor (GM-CSF), however, elevated inflammatory chemokines such as RANTES. In addition, gap junction channel protein expression and mediated intercellular communications were attenuated after 5-FU treatment. Significantly, co-culture on 5-FU treated HS-5 feeder layer resulted in less quantity of human umbilical cord blood-derived hematopoietic cells and CD34⁺ hematopoietic stem/progenitor cells (HSPCs), and SIPS of hematopoietic cells. However, it is noteworthy that ASP ameliorated SIPS of hematopoietic cells by the mechanism of protecting bone marrow stromal cells from chemotherapeutic injury via mitigating oxidative damage of stromal cells and improving their hematopoietic function. This study provides a new strategy to alleviate the complication of conventional cancer therapy using chemotherapeutic agents.

Age-related regression in hematopoietic stem/progenitor cells (HSC/HPCs) limits replenishment of the blood and immune system and hence contributes to hematopoietic diseases and declined immunity. In this study, we employed D-gal-induced aging mouse model and observed the antiaging effects of Angelica Sinensis Polysaccharide (ASP), a major active ingredient in dong quai (Chinese Angelica Sinensis), on the Sca-1⁺ HSC/HPCs in vivo. ASP treatment prevents HSC/HPCs senescence with decreased AGEs levels in the serum, reduced SA-β-Gal positive cells, and promoted CFU-Mix formation in the D-gal administrated mouse. We further found that multiple mechanisms were involved: (1) ASP treatment prevented oxidative damage as total antioxidant capacity was increased and levels of reactive oxygen species (ROS), 8-OHdG, and 4-HNE were declined, (2) ASP reduced the expression of γ-H2A.X which is a DNA double strand breaks (DSBs) marker and decreased the subsequent ectopic expressions of effectors in p16Ink4a-RB and p19Arf-p21Cip1/Waf senescent pathways, and (3) ASP inhibited the excessive activation of Wnt/β-catenin signaling in aged HSC/HPCs, as the expressions of β-catenin, phospho-GSK-3β, and TCF-4 were decreased, and the cyto-nuclear translocation of β-catenin was inhibited. Moreover, compared with the positive control of Vitamin E, ASP exhibited a better antiaging effect and a weaker antioxidation ability, suggesting a novel protective role of ASP in the hematopoietic system.

The protective effect and mechanism of Ginsenoside Rg1 on aging mouse pancreas damaged by D‑galactose (D‑gal)‑induced was studied. Two-month-old male C57BL/6J mice were randomly divided into three groups of 10 mice per group. The D‑gal group of mice received hypodermic injection of D‑gal (120 mg/kg/day) for 42 days; the Rg1+D‑gal group of mice receiving D‑gal + intraperitoneal injection Rg1 (40 mg/kg/day) for 27 days from the 16th day of D‑gal replication; and the naïve group that constituted the normal control mice receiving the same dose of saline instead of the drug. The related indicators were tested on the second day after modeling and administration. Fasting blood glucose (FBG), oral glucose tolerance test (OGTT) and fasting insulin level were measured by taking peripheral blood. Samples of pancreas were weighed and visceral index was calculated. Paraffin sections were prepared. H&E staining sections were produced to observe pancreatic tissue morphology. Immunohistochemical staining was used to observe advanced glycation end products (AGEs) and integral optical density (IOD) of stained positive tissue in pancreas. Ultrathin slices were used to observe ultrastructural change of pancreatic tissue. Frozen sections were prepared to test the relative optical density of positive cells that were stained by senescence‑associated β‑galactosidase (SA‑β‑gal) in pancreatic tissue. Superoxide dismutase (SOD), malonalde­hyde (MDA) and total antioxidant capacity (T‑AOC) were detected by preparing pancreas tissue homogenates. Compared with the control group, Rg1+D‑gal mice had significantly decreased pancreatic wet weight and visceral index and significantly lower FBG; OGTT for 30 and 120 min. There was no significant difference of the blood sugar level between the groups. The area under the curve and the number and size of the nucleated cells within islet were markedly reduced. In addition, SA‑β‑gal‑positive particles in pancreas tissue intracytoplasmic cells significantly decreased and relative optical density also reduced. The IOD of AGEs in pancreas tissue and MDA content decreased. SOD and T‑AOC activity significantly increased. Ginsenoside Rg1 can be effective antagonistic structure and function of the pancreas injury induced by D‑gal. The mechanism may be associated with reducing oxidative damage.