Influence of ciliary neurotrophic factor on spinal cord caspase-3 expression in rats of different age following sciatic nerve damage
- VernacularTitle:不同年龄大鼠坐骨神经损伤后睫状神经营养因子对脊髓组织中天冬氨酸特异酶切的半胱氨酸蛋白酶3表达的影响
- Author:
Tao LI
;
He WANG
;
Yu ZHUO
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2005;9(37):166-169
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND: Caspase-3 is a cysteine proteinase that can promote cell apoptosis. Ciliary neurotrophic factor has many kinds of biological activities, such as protecting various neurons from injury, especially motorial neurons, thereby reducing the occurrence of nerve cell injury.OBJECTIVE: To observe the Influence of ciliary neurotrophic factor on spinal cord caspase-3 expression in different ages rats following sciatic nerve injury, aiming to make further investigation about the changing regularity and modulating character of peripheral nerve damage at various ages rats.DESIGN: Randomized controlled experiment.SETTING: Ultrasound Department and the 5th Research Institute of Daping Hospital, Field Surgery Research Institute of the 3rd Military Medical University of Chinese PLA.MATERIALS: This experiment was carried out at the Field Surgery Research Institute of the 3rd Military Medical University of Chinese PLA from April 2000 to December 2001. Altogether 810 wistar rats including infant rats with body mass of 30-100 g (birth age of 20 days), adult rats of 200-350 g (birth age of 4 m), elder rats of 400-800 g (birth age of 18-24 m),were selected with 270 rats in each age stage. Female and male does not limit.METHODS: [1] Experimental animal grouping: Various age rats were randomly divided into normal group (n=18), ciliary neurotrophic factor group(n=126) and physiological saline group (n=126), rats in ciliary neurotrophic factor group and physiological saline group were subdivided into 1 day, 3days, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks subgroups. [2] Animal model preparation: In Ciliary neurotrophic factor group and physiological saline group, rats were cut off a piece of sciatic nerve of 2 mm long, both ends connected with silica tube for constructing neuranagenesis cab, in which 15 μL recombined ciliary neurotrophic factor (25 mg/L) was injected in ciliary neurotrophic factor group, and 15 μL physiological saline in physiological saline group. [3] Preparation and examination of specimen:Six rats were randomly selected from each group, lumbar L3-5 spinal cord were obtained for carryingonnation, caspase-3 activity examination and Western blotting examination.MAIN OUTCOME MEASURES: [1] Expression of spinal cord caspase-3 with IHC assay. [2] Distribution and expression intensity of spinal cordcaspase-3 by Western blotting technique. [3] Changes in caspase-3 activity.RESULTS: Altogether 810 rats completed the experiment, all data was entered the final result analysis. [1] Expression of spinal cord caspase-3 with IHC assay: After injury, neuronal caspase-3 expression became strengthened at injured side of various age physiological saline groups, which obviously increased at posttraumatic 2 weeks and 4 weeks, but less expressed at 8 weeks and 12 weeks; while in ciliary neurotrophic factor group, posttraumatic caspase-3 expression was mostly obvious at 2 weeks and 4 weeks. [2] Distribution and expression intensity of spinal cordcaspase-3 by Western blotting technique: Caspase-3 expression was not significant difference between various age subgroups in normal group(P ＞ 0.05). Comparing to the same age normal group and non traumatic group, caspase-3 expression was strengthened at 1 week, 2 weeks, 4 weeks in various age physiological saline group and ciliary neurotrophic factor group damages (P ＜ 0.05-0.01); in ciliary neurotrophic factor group, caspase-3 showed weaker expression at 1 week, 2 weeks, 4 weeks in infants; 2weeks and 4 weeks in adults, 4 weeks in elders comparing to corresponding physiological saline group, difference was significant (P ＜ 0.05-0.01).The comparison between untraumatic side of each group and normal group showed no statistical difference (P ＞ 0.05). [3] Changes in caspase-3 activity: In child, adult and elder physiological saline groups, caspase-3 activity was increased in traumatic spinal cord, moreover caspase-3 activity was higher than elder and adult group at various age point (P ＜ 0.05-0.01); in child, adult and elder ciliary neurotrophic factor groups, caspase-3 activity is lower than physiological saline group (P ＜ 0.05-0.01). After damage,caspase-3 activity at traumatic side in physiological saline group and ciliary neurotrophic factor group was difference from normal group but without significant meaning (P ＞ 0.05), except the expression in child posttraumatic 12 weeks group was lower than normal group (P ＜ 0.05).CONCLUSION: After sciatic nerve damage, caspase-3 protein expression and activity were found to be increased in spinal cord of different age groups rats which can be reduced by extragenous ciliary neurotrophic factor, which playing protective role on spinal cord nerve cells, such protection would gradually attenuated in child group, adult group to elder group in turns.
