Objective:

2

To evaluate the effect of Guilu Erxian Glue (龟鹿二仙胶

GEG) on cyclophosphamide (CTX)-induced bone marrow hematopoietic stem cells (HSCs) senescence in mice and explore the underlying mechanism.

Methods:

2

The H

22

liver cancer ascites lump model was established in male Kunming mice by injecting intraperitoneally (i.p.) with 5×10

6

/mL H

22

cells per mouse. Fifty tumor-bearing mice were divided into the control

model

pifithrin-α

GEG

and GEG+pifithrin-α groups using a random number table

10 mice in each group. CTX (100 mg/kg i.p.) was administrated to mice from day 1 to day 3 (d1–d3) continuously except for the control group. The mice in the pifithrin-α

GEG and GEG+pifithrin-α groups were treated with pifithrin-α (2.2 mg/(kg•d) i.p.) for 6 consecutive days (d4–d9)

GEG (9.5 g/(kg•d) i.p.) for 9 consecutive days (d1–d9)

and GEG plus pifithrin-α

respectively. HSCs were collected after 9-d drug treatment. The anti-aging effect of GEG was studied by cell viability

cell cycle

and β-galactosidase (β-gal) assays. The mRNA and protein expressions of cyclin-dependent kinase 2 (CDK2)

CDK4

inhibitor of cyclin-dependent kinase 4a encoding the tumor suppressor protein p16 (p16

INK4a

)

p21

Cip1/Waf1

p53

and phosphorylated retinoblastoma (pRb) were evaluated by quantitative real-time reverse transcription-polymerase chain reaction and semi-quantitative Western blot

respectively.

Results:

2

Compared with the model group

GEG increased cell viability as well as proliferation (

P

<

0.05 or

P

<

0.01) and reduced β-gal expression. Furthermore

GEG significantly decreased the expressions of p16

INK4a

p53 and p21

Cip1/Waf1

proteins

and increased the expressions of CDK2

CDK4 and pRb proteins compared with the model group (

P

<

0.05 or

P

<

0.01).

Conclusion:

2

GEG can alleviate CTX-induced HSCs senescence in mice

and the p16

INK4a

-Rb signaling pathway might be the underlying mechanism.