Protection of motoneurons from spinal root avulsion induced cell death by Schwann cell derived neurotrophic factor
- VernacularTitle:许旺细胞源神经营养因子对脊神经根性撕脱所致神经元死亡的干预
- Author:
Lijun LIU
;
Jiakai ZHU
;
Jiande XIAO
;
Daping WANG
;
Lei YANG
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2006;10(33):168-170,封三
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND: Schwann cell derived neurotrophic factor, which is isolated and purified from the kytoplasm of Schwann cell with the relative molecular mass of 58000, is a kind of neurotrophic substance possessing obvious neurotrophic activity. It can be against neurovirulent substance of nitrogen monoxidum.OBJECTIVE:To create root avulsion animal models and observe the protective effects of Schwann cell derived neurotrophic factor (SDNF) on motoneurons of spinal anterior horn from spinal root avulsion induced cell death.DESIGN: Repeated observation and measure.SETTING: Third Department of Orthopaedics, Second People's Hospital of Shenzhen; Department of Micro-surgery , First Hospital Affiliated to Sun Yat-sen University.MATERIALS: This experiment was conducted at the Experimental Animal Center of Medical College of Sun Yat-sen University from March to May 2003. Twenty Sprague-Dawley rats with the age of 3-4 months, of clean degree, were selected and divided randomly into experimental group of Schwann cell derived neurotrophic factor and control group of normal saline with 10 rats in each group. The right side was injured, and the left side was intact served as normal control side.METHODS : ①A rat model of C6,7 spinal root avulsion induced motoneuron degeneration was established. ② A small piece of gelfoam presoaked in 40 μL SDNF solutions (1 g/L) was placed in contact with the injured spinal cord in the animals of the experimental group. Normal saline was added as the same way as above in the animals of the control group. ③ A silica pipe was put on the surface of gleform, one end of the silica was sutured to the glefoam , and the other end wasfixed subcutaneously with vaselinum. Local intramuscular injection of penicillinum was performed on the wound following closing the incision. All rats received an injection (20 μL) of either SDNF or normal saline solution at the lesion site through the silica pipe sutured to the glefoam once a week after the surgery. All the animals were killed by the end of the third weeks. ④The spinal region of C6,7 level was dissected out for observing survival rate and morphological change of motoneurons of spinal anterior horn as well as the expression of nitricoxide synthase(NOS).MAIN OUTCOME MEASURES: ① Survival and morphological change of spinal motor neurons. ②Change of nitricoxide synthase expression of spinal motor neurons.RESULTS: Totally 20 rats were enrolled in the experiment, and all of them entered the stage of result analysis. ① Survival and morphological changeof spinal motor neurons: 68.6% motoneurons of injured side of the control group died at 3 weeks after surgery. The survival rate was 31.4%,which was significantly lower than that of the intact side (P ＜ 0.01), and the survived neurons was shrinked significantly; the death rate of spinal motor neurons of injured side of experimental group was decreased by 35%as compared with control group (P＞ 0.05). The survival rate was 66.4%,and the survived neuron body was increased, similar to the intact side (P ＞ 0.05). ② Change of nitricoxide synthase expression of spinal motor neurons: In normal spinal cord, NOS positive neurons were shown in dorsal horn, surrounding the central canal and in the intermediolateral column.NOS was not seen in the anterior horn motonurons. At the end of the third week after C6,7 spinal root avulsion, increased NOS expression was not found at the injured side in the Schwann cell derived neurotrophic factor group and the intact side in the control side, while the significantly increased NOS expression of spinal motoneurons was found at the injured side of the control group.CONCLUSION: Degeneration of spinal motoneuron and increased expression of NOS can be induced by spinal root avulsion. SDNF has a significant effect in protecting spinal motoneurons from spinal root avulsion induced cell death and inhibiting the expression of NOS. These results suggest that the effects .of SDNF on motoneuron survival may be achieved by modifying the expression of certain cellular molecule such as NOS.
