Objective: To observe the effects of Youdujing preparation on the proliferation and apoptosis of cervical immortalized cells (H8 cells) and explore the possible mechanism. Method: H8 cells

which were transfected with HPV-16 gene and passed stably

were chosen to be the object of the study. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay was used to detect the proliferation inhibition of H8 cells after being treated with 1

2

3

4

5 g·L-1 Youdujing for 24

48

72 hours. Meanwhile

the blank was set up for parallel control. MTT was used to detect the inhibitory effect on cell proliferation. Apoptotic changes of cells that were intervened by 1

2

3

4

5 g·L-1 Youdujing for 24 h and stained by Hoechst 33342 were observed by fluorescence microscope. Flow cytometry was used to detect the early-stage apoptotic rate of H8 cells after being double stained with Annexin V/propidium iodide (PI). Expressions of Caspase-3 protein and Poly ADP-ribose polymerase (PARP) protein in H8 cells

which were treated with 1

2

3

4

5 g·L-1 Youdujing for 24 h

were tested by Western blot method. Result: The growth of H8 cells intervened by 1

2

3

4

5 g·L-1 Youdujing was significantly inhibited in concentration-dependent and time-dependent manners (P<0.05)

compared with blank group. According to Hoechst 33342 staining

nuclear chromatin condensations were observed after being intervened by 1

2

3

4

5 g·L-1 Youdujing for 24 h

and round

bright blue apoptotic bodies increased after being treated with 3

4

5 g·L-1 Youdujing. The early-stage apoptotic rates of cells treated with 1

2

3 g·L-1 Youdujing were (23.73±5.72)%

(63.9±3.59)%

(71.53±1.59)%

respectively

according to flow cytometry

which were significantly higher than that of control group(6.53±0.85)%(P<0.01). Caspase-3 and PARP proteins were consistently down-regulated in H8 cells (P<0.05). Conclusion: Youdujing preparation can inhibit H8 cell growth and induce early-stage apoptosis in H8 cells

which may be implemented by activating Caspase-3-PARP.