2.4 | Transmission electron microscopy detection
After harvesting the LF specimens during the operation, they were immediately cut into small pieces of approximately 0.8 mm3. Subsequently, the small pieces of LF specimens were fixed in 2.5% glutaraldehyde for 3 h. Next, the sample sections were washed 3 times for 15 minutes using phosphate-buffered saline (PBS). After dehydrating with propylene oxide 3 times for 30 minutes each time, they were embedded in Epon. Then, the specimens were cut into ultrathin sections of 70 nm thickness using an ultramicrotome (EM UC7, Leica, Germany). Finally, the sections were stained with 2% uranyl acetate. The morphology and structure of LF was analyzed under a transmission electron microscope (LVEM5, Delong, America).