Effect of Matrigel on the establishment of human osteosarcoma animal model

Abstract

Objective To investigate the effects of cell suspension including Matrigel, normal culture medium and phosphate buffer saline (PBS) on the xenograft model establishment of human osteosarcoma. The function of Matrigel on regulating human osteosarcoma cell differentiation and proliferation was analyzed. Methods Twenty-four BALB/c-nu/nu nude mice were randomly divided into three groups with 8 animals in every group: Matrigel and RPMI 1640 suspension (group M), RPMI 1640 culture medium (group R), PBS (group P). Human osteosarcoma cell-SaOS-2 was suspended in the three groups respectively. 1×106/ml equivalent cell counts were injected into the back of each anesthetized nude mouse (400 μl per mouse). Xenograft tumors were measured at regular intervals and the tumor volume was calculated. After 5 weeks of inoculation, the tumor parts were dissected. Paraffin-embedded sections from xenograft tumor tissues were fixed in 4 % paraformaldehyde and pathological study was made after paraffin embedding and cutting under microscope by HE stains. Results Eight nude mice formed tumor lumps at 0 day in group M and were gradually increased over time. Xenograft tumors of group R and group P disappeared in 2-4 days and some appeared again after 1 week with an increase of tumor size. After 5 weeks, the tumor volume in the group M was significantly larger than that in the group P and group R [(3 185 ± 488), (598 ± 189), (512 ± 109) mm3 respectively, F= 85.7, P 0.05). Histopathological analysis showed that cells in the group M could keep original degrees of pathological differentiation in osteosarcoma cells. Besides, cells suspension of culture medium or PBS in the group P and group R were poorly differentiated. Conclusions Matrigel can promote high tumor growth rate and good uniformity of human osteosarcoma cells in experimental animals. The histological state is similar to original structure, which conforms to the occurrence and development of human osteosarcoma. Key words: Osteosarcoma; Models, animal; Transplantation; Matrigel