Interleukin-10 gene therapy for neuropathic pain in a rat model of chronic constriction injury / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of intrathecal IL-10 gene on neuropathic pain induced by chronic constriction injury (CCI) to the sciatic nerve. Methods Sixty female SD rats weighing 230-250 g were anesthetized with pentobarfaital. Right sciatic nerve was exposed at the midthigh level and 4 ligatures were placed on the sciatic nerve with 4.0 catgut at 1mm interval. Intrathecal catheter (PE-10 tubing) were inserted at L5,6 interspace and correct placement was confirmed by outflow of CSF. The animals were randomized into 5 groups ( n = 12) group Ⅰ sham operation; group Ⅱ CCI; group Ⅲ,Ⅳ and Ⅴ received intrathecal (IT) normal saline (NS) (Ⅲ) or pcDNA 3.1 (Ⅳ) or pcDNA 3.1-IL-10 (Ⅴ) 3 days after CCI when the animals developed thermal hyperalgesia. Threshold to noxious thermal stimuli was measured before CCI (baseline), before and 2, 4, 7, 10 and 14 days after IT injection. CSF was collected on 1, 3, 7 and 10 days after IT injection for determination of CSF IL-10 concentration. Six animals were killed on 3rd and 14th days after IT injection respectively in each group and the sciatic nerve, lumbar segment of spinal cord ( L3-6) and hippocampus were isolated and blood was collected for determination of IL-10 mRNA expression (by RT-PCR) (on 3rd day after IT) and TNF-? content (on 14th day after IT) .Results Paw removal latencies were significantly longer 2-14 days after IT injection in group Ⅴ(CCI + pcDNA 3.1-IL-10) than in group Ⅲ (CCI + NS) and Ⅳ (CCI + pcDNA 3.1). The IL-10 mRNA expression in sciatic nerve, lumbar segment of spinal cord and hippocampus was significantly higher 3 days after IT injection while their TNF-? contents were significantly lower 14 days after IT injection in group Ⅴ than in the other 4 groups. The CNS IL-10 concentration on day 1-7 after IT injection was significantly higher in group Ⅴ than in the other 4 groups. Conclusion Intrathecal IL-10 gene injection can ease pain induced by CCI of the sciatic nerve through inhibition of inflammatory response.