[Establishment of PD-L1 transgenic mouse model and recovery of the motion after spinal cord injury].

ABSTRACT

AIM: To establish a ubiquitously expressed PD-L1 transgenic mouse model and evaluate its recovery of motor function after spinal cord injury. METHODS: Clone and sequence the complete mouse PD-L1 cDNA and construct the pCAG-PD-L1 transgenic vector by inserting the PD-L1 cDNA into the pCAGGS vector. The PD-L1 transgenic (TgPD-L1) mice were established by pronuclear micro-injection with fertilized eggs from C57BL/6 mice and the genotypes were confirmed by PCR with tail genomic DNA. The expression of PD-L1 on T and B lymphocytes from mouse spleen were detected by flow cytometry. The expression of PD-L1 in peripheral tissues was displayed by immunohistochemistry. The expression level of PD-L1 in spinal tissue was evaluated by RT-PCR. The recovery of motor function was analyzed by Basso-Beattie-Bresnahan(BBB) locomotion testing system at 3, 7, 14, 21, 28 and 35 day after spinal severe crush with forceps in mice. RESULTS: Three lines of TgPD-L1 mice in C57BL/6 background were generated and the exogenous PD-L1 gene can be heritable steadily to offsprings. PD-L1 was highly exppressed in spinal tissue, peripheral tissues, T and B lymphocytes using RT-PCR, immunohistochemistry and flow cytometry respectively in TgPD-L1 mice. The BBB scores were obviously higher at 21 day post-injury in TgPD-L1 than those of in WT mice (P<0.05). CONCLUSION: The TgPD-L1 mice whose background are C57BL/6 were established successfully and high expression level of PD-L1 in tissues promotes locomotion recovery after spinal cord injury in TgPD-L1 mice.