[The pathogenesis of CD4(+)T cells infiltrated into the spinal cord in rat SNL model]

To explore the infiltration pathogenesis of CD4(+);T cells following the spinal nerve ligation.Healthy adult male SD rats were randomly divided into the spinal nerve ligation group (Tx), sham operation group (S), control group (C). the 50mechanical paw withdrawal threshold ( 50MWT ) was determined by up-down method; CD4(+);T cells infiltration was assessed by FACS; the mRNA levels of CCL2, CCL5 and CXCL10 were quantitated by RT-qPCR; serum cytokines were tested by ELISA kits.After 3 days since operation, 50MWT of Tx group was significantly reduced (P0.01) comparing with S group, C group; on day 14, 50MWT was up to the minimum value; whereas S group and C group were no difference (P0.05). After 7 days since operation, CD4(+);T cells infiltration into lumbar segments of the spinal cord in the Tx group increased significantly (P0.01), and the CCL2, CCL5mRNA expression increased (P0.05); on day 14, the CD4(+);T cells infiltration in Tx group was higher than S group, C group; but there was no statistical significance. On day 7 and 14 days, serum levels of cytokines were no difference in the three groups.Following spinal nerve ligation, high expression of chemokine promoted peripheral CD4(+);T cells to infiltrate into spinal cord; and the infiltrated CD4(+);T cells maintained the neuropathic pain.