ABSTRACT
AIM: To investigate the possibility of transfecting siRNA into rabbit cervical cells in transformation zone by the method of solid phase in vivo and to verify the effectivity of siRNA transfection by modifying the permeability of the cervical epithelium. METHODS: A sense strand small-interference RNA (siRNA) for human papillomavirus type 16 (21 bp) was designed and labeled with Cy3. siRNA-Lipo2000-carbomer gum was prepared. Twelve rabbits were included in the study and divided into experimental group and control group. In order to modify the permeability of cervical epithelium, hypertonic saline solution at concentration of 200 mmol/L was used to infuse the cervix in the experimental rabbits for 10 min, and normal saline was used for the control animals. The siRNA-Lipo2000-carbomer gum was applied to the surface of the rabbit cervix. Twenty-four hours later, the rabbits were sacrificed, and the cervix was isolated, cut into 2 parts, one part was for rapid frozen sectioning and the efficiency of transfection was observed under fluorescence microscope, another part was prepared by paraffin embedding and sectioning, and the form of cervical histiocytes was observed. Twelve SCID mice with SiHa cell cervical tumor, divided into experimental group and control group, were also used in the study. The mice in experimental group were treated with siRNA-Lipo2000-carbomer gum for 7 d. The control mice were treated with Lipo2000-carbomer gum only. Five days later, the mice were sacrificed and the tumor was collected, and the HPV16-DNA was measured by PCR. RESULTS: (1) Red fluorescence (Cy3) in cervical epithelium was observed in all rabbits. However, no different effect of siRNA transfection was found between the ways of modifying the cervical epithelium permeability. (2) No abnormal change such as flare, swelling and ulcer at all cervical tissue was observed, the cervical cell form was normal. (3) The titer of HPV16-DNA was decreased significantly after siRNA transfection (P<0.05). CONCLUSION: Transfection of siRNA into rabbit cervical epithelium in vivo is successful by using the method of solid phase and inhibits the processes of HPV-DNA, indicating that using RNAi is a practical way to treat HPV infection in human cercix and to decrease the incidence of cercical carcinoma.