2.13 | Rabbit LF degeneration and hypertrophy model
All surgical and experimental procedures were approved by the ethics
committee
of Nanjing Medical University. Nine New Zealand white rabbits, weighing
approximately 3.0 kg, were randomly divided into three groups in this
study. The rabbits were anesthetized using 3% pentobarbital chloral
hydrate (3ml/kg) and prevented infection by injection of antibiotics
(10mg/kg of cefazolin sodium pentahydrate; Shenzhen, China) via the ear
vein. Then, the rabbits were placed into a prone position. A dorsal
midline skin incision approximately 6 cm was performed under X-ray
control. As described previously (Hayashi et al., 2017), lumbosacral
fascia was cut left lateral to the mammillary process, and then
discovered the gap between the multifidus and longissimus muscles.
Subsequently, we detached the the multifidus from the mammillary
processes to expose the lamina, the root of the transverse process and
posterior edge of vertebral body. The Group A just underwent surgical
exposure without fixation as a control operation (n=3). The Group B
underwent posterolateral fusion with instrumentation (Watson locking
plate; Changzhou, China) and performed additional resection of L3-4
supraspinal muscle and interspinous ligament to obtain mechanical stress
concentrating on L3-4 level (n=3). Briefly, 4-hole titanium locking
plate was used on the left posterolateral side of L2-3 and L4-5, and a
2mm×10mm titanium locking screw was then inserted into each vertebra and
locked to obtain mechanical stress concentrating on L3-4 level. Rabbits
in Group C were treated with cyclopamine (50mg/kg every day,
subcutaneous injection as described previously (Berman et al., 2003;
Berman et al., 2002)) except for the same surgical procedure in Group B
(n=3). All rabbits were raised independently with free access to food
and water. Three groups of rabbits were sacrificed at 12 weeks after
surgery.