Investigating Circulating RNA in Nude Mice

In this experiment, 20 nude mice (male, 4 weeks old) (both Beijing Huafukang Biotechnology Co., Ltd., Beijing, China) were selected and raised in sterile laminar flow animal rooms (SPF grade). Lentivirus plasmids of short hairpin RNA (shRNA) against circ-10720 (sh-circ-10720) and negative control (sh-NC) were constructed by Genepharma (Shanghai, China). Cells were infected with lentiviral particles of sh-circ-10720 or sh-NC, and then, nude mice were injected with 2 × 10⁶ cells into the subcutaneous area of the right back. The date and time of cell inoculation were recorded, and each nude mouse was marked. After 7 days, the longest diameter (length) and shortest diameter (width) of the tumors were measured with a ruler sterilized by UV radiation. After that, tumor volume was calculated: π/6 × (length × width)². After 4 weeks, mouse euthanasia was done with CO₂, and tumors were weighed [35 (link)].