Majallah-i Dānishgāh-i ̒Ulūm-i Pizishkī-i Bābul (Jun 2009)
Analgesic Effect of Intrathecal Transplantation of Adrenal Medullary Tissue and Histogranin in Neuropathic Rats
Abstract
BACKGROUND AND OBJECTIVE: Neuropathic pain is a consequence of disease or trauma to peripheral nerves or the central nervous system. In spite of so many people suffering from neuropathic pain it is still extremely difficult to treat. The aim of this study was to examine the cumulative effect of adrenal transplantation and intrathecal injection of histogranin (HN) on pain behavior in neuropathic rats.METHODS: In this experimental research 20 rats were allocated to 2 groups, 10 rats in each. One week after unilateral sciatic nerve ligation using chronic constriction injury (CCI) model, animals received either adrenal medullary or control striated muscle tissue transplantation in lumbar part of spinal cord. One week after animals received different doses of HN (0.5, 1, 3, 6 µg/10ml) or saline interathecally. Behavioral tests were preformed before induction of CCI, before transplantation, before injection and 10 min after injection of HN.FINDINGS: CCI caused heat and mechanical hyperalgesia. In adrenal transplanted animals heat and mechanical thresholds in animals which received low dose of histogranin (0.5 mg/kg) was 9.3±0.6 and 9.5±1.1, respectively which increased comparing to before injection time (p<0.05). Injection of 6 µg HN was not effective. In muscle transplanted animals only higher dose of histogranin increase thermal threshold. Thermal threshold in this groups increased from 6.4±0.35 before injection time to 9±0.9 after injection of 3 µg of HN (p<0.05). However alleviation of pain was significant with the lower doses of histogranin in adrenal medullary transplanted animals (p<0.05). CONCLUSION: The results showed that the pain alleviation effect of histogranin when accompained with adrenal medullary graft is dose dependant and low doses of histogranin can augment the effects of adrenal medullary transplants and may be an effective adjunct in the treatment of chronic pain.
