Abstract:

BACKGROUND: Many studies have confirmed that the subarachnoid implantation of microencapsulated adrenal chromaffin cells can relieve chronic pain in rodent models. An ethical argument surrounds the implantation of animal (xenogenic) adrenal chromaffin cells for human pain therapy, and the availability of human chromaffin cells is very limited. Thus, a new source of cells must be explored for cellular transplantation in pain therapy.
OBJECTIVE: To investigate the potential of microencapsulated PC12 cells to improve cold allodynia in a rat model of chronic neuropathic pain.
METHODS: Thirty-six Spraque Dawley rats with chronic constrictive injury were divided randomly into three groups: alginic-polylysine-alginic (APA) microencapsulated PC12 cell group, bare PC12 group and empty capsule group. The subarachnoid implantation was performed at 3-5 days after microcapsulation.
RESULTS AND CONCLUSION: After transplanted with APA-PC12, the difference in retracted frequency and time between two hind legs of rats was significantly decreased which compared with the results pre-transplantation (P < 0.01). Meanwhile, the differences were significantly lower than those in the bare PC12 group and empty capsule group (P < 0.01). The levels of met-enkephalin and norepinephrine in the cerebrospinal fluid of rats in the APA-PC12 group were significantly higher than those in the bare PC12 group and empty capsule group (P < 0.01) at week 7 after transplantation. These results suggest that subarachnoid implantation of microencapsulated PC12 cells can suppress cold allodynic behavior in a rat model of neuropathic pain. Increased levels of met-enkephalin and norepinephrine are found in the cerebrospinal fluid.