ABSTRACT
P2X4 and P2X7 receptors play an important role in neuropathic pain after spinal cord injury. Regulation of P2X4 and P2X7 receptors can obviously reduce pain hypersensitivity after injury. To investigate the role of neural stem cell transplantation on P2X receptor-mediated neuropathic pain and explore related mechanisms, a rat model of spinal cord injury was prepared using the free-falling heavy body method with spinal cord segment 10 as the center. Neural stem cells were injected into the injured spinal cord segment using a micro-syringe. Expression levels of P2X4 and P2X7 receptors, neurofilament protein, and glial fibrillary acidic protein were determined by immunohistochemistry and western blot assay. In addition, sensory function was quantitatively assessed by current perception threshold. The Basso-Beattie-Bresnahan locomotor rating scale was used to assess neuropathological pain. The results showed that 4 weeks after neural stem cell transplantation, expression of neurofilament protein in the injured segment was markedly increased, while expression of glial fibrillary acidic protein and P2X4 and P2X7 receptors was decreased. At this time point, motor and sensory functions of rats were obviously improved, and neuropathic pain was alleviated. These findings demonstrated that neural stem cell transplantation reduced overexpression of P2X4 and P2X7 receptors, activated locomotor and sensory function reconstruction, and played an important role in neuropathic pain regulation after spinal cord injury. Therefore, neural stem cell transplantation is one potential option for relieving neuropathic pain mediated by P2X receptors.
ABSTRACT
Based on the time series of ecological footprint (EF) in Jilin Province from 1994 to 2003, the relationship models of EF, ecological budget, and EF intensity with urbanization level were established. The results showed that in Jilin Province, there existed significant correlations of EF, ecological budget, and EF intensity with urbanization level. Along with the development of urbanization, the EF in the Province increased from 1.59 hm2 x cap(-1) in 1994 to 2.23 hm2 x cap(-1) in 2003, which was mainly affected by the process of urbanization and the proportion of tertiary industry. The EFs of built-up land, pasture and fossil fuel land changed more markedly, among which, the EFs of pasture and fossil fuel land were mainly affected by domestic consumption, while that of built-up land was mainly affected by the GDP per capita and the proportion of tertiary industry. Owing to the increase of domestic consumption, the ecological deficit increased from 0.319 hm2 cap in 1994 to 0.923 hm2 cap(-1) in 2003. The changes in ecological budget of pasture and fossil fuel land were more remarkable. Under the effects of the optimization of economic structure and consumption structure, the EF intensity in the Province decreased from 4.14 hm2 x (10(4) Yuan)(-1) in 1994 to 2.35 hm2 (10(4) Yuan)(-1) in 2003, and there still had enough potential for the decrease. Through the optimization of economic structure and consumption structure, an ecological surplus and the balance between natural resources supply and demand in the Province could be achieved.
