Rabbit immunoglobulin g igg

All animal protocols were approved by the local government agency (Department of Health, Hong Kong SAR) and institutional ethics committee (CULATR), and performed in accordance with relevant guidelines and regulations. The University of Hong Kong is an AAALAC accredited facility and follows guidelines of the Department of Health, Special administrative region of Hong Kong. All procedures were performed in accordance with Cap. 340 Animals (Control of Experiments) Ordinance and Regulations established by the Department of Health. Four month-old female Lewis rats were anesthetized (Ketamine:Xylazine, 2:1, 1 ml/kg i.p.). Radiographs were taken to locate caudal disc levels 4–5, 5–6, and 6–7. The tail skin was sterilized and was longitudinally incised over target disc levels. The discs were perpendicularly inserted with a 34 G gauge needle (Hamilton) at a depth of 3 mm through the anulus fibrosus, followed by injection of 2ul 200ug/ml CDH2 ectodomain antibody (Santa Cruz) or rabbit immunoglobulin G (IgG, Santa Cruz) into the nucleus pulposus. The skin and muscles were sutured and the animals were allowed to move freely in the cage after the operation. Animals were sacrificed at multiple time points from 2 to 8 weeks after injection (n = 3 per timepoint).