Abstract

The aim of this study was to investigate the efficiency of intrathecal glial cell line-derived neurotrophic factor (GDNF) on nitric oxide (NO) and nitric oxide synthase (NOS) activity following a spinal nerve ligation (SNL) of male Sprague Dawley rats. The rats were randomly divided into four groups: normal (control), sham-operated, SNL (SNL followed by a physiological saline injection into the subarachnoid space), and GDNF (SNL followed by a GDNF injection into the subarachnoid space). Each group was divided into three subgroups (n = 10). The rats in each subgroup were euthanised 3, 7, and 14 days after the operation. Rat behaviour was evaluated before euthanising, and the ipsilateral spinal cords were harvested after euthanising to determine the NO content and NOS activity. Compared with the control and sham-operated groups, the NO content and NOS activity in the SNL group increased significantly 3 days after the operation; this increase was maintained until 14 days after the operation (P < 0.01 or 0.05). A significant decrease was observed in the NO content and NOS activity in the GDNF group compared with the SNL group. The decrease continued until 14 days after the operation (P < 0.01 or 0.05). The results indicated that the NO and NOS activity in the rat spinal cord are associated with SNL-induced neuropathic pain. The decreased neuropathic pain from the intrathecal GDNF is correlated with the decrease in NO content and NOS activity in the spinal cord.

Key words: Glial cell line-derived neurotrophic factor, neuralgia, nitric oxide, nitric oxide synthase.