损毁弓状核对幼年大鼠骨生长发育的影响

Effects of damaging of arcuate nucleus on bone growth and development in male juvenil rats

目的:观察新生期注射谷氨酸单钠(MSG)破坏下丘脑弓状核大鼠,35日龄及70日龄股骨、胫骨生长、发育的情况。方法:新生期SD大鼠皮下注射10%谷氨酸单钠,饲养至第35天、第70天处死,检测各项指标。结果:MSG大鼠35日龄时,弓状核神经细胞大面积损毁,损毁率达50%—60%,伴有垂体、睾丸重量减轻、四肢骨明显变短(P<0.05),其余指标开始变化。至70日龄时,MSG大鼠上述各项指标进一步发展,弓状核神经细胞损毁率达70%—80%,血清中T、E2水平显著下降,伴有股骨湿重、干重、体积骨密度明显减轻,胫骨骨小梁面积、数量、宽度显著下降,而分离度明显升高。结论:损毁弓状核首先导致骨生长发育障碍,继而发生骨质疏松。前者主要与下丘脑-GH-IGF-I轴有关,后者主要与下丘脑-垂体-性腺轴有关。

Objective：To research the effects of damaging of arcuate nucleus（ARC） on bone growth and development in 35d and 70d rats.Method：Newborn SD rats were injected with monosodium glutamate hypodermically once every other day.After surviving 35d and 70d,the rats were killed and examine the changes of markers.Result：Compared with control group（35d）,the lesion degree of hypothalamic in MSG group of 35d approximately 50%--60% the average, body length is evidently shorter and the femur was shorter and slimmer. The lesion degree of the hypothalamic ARC in MSG group of 70d is approximately 70%--80%. Meanwhile, MSG rats （70d） were stunted, and had smaller pituitaries and testis. The level of serum E2 and T were both lower. The wet weight,dry weight and BMD of the femur obviously reduced. The parametes had significant changes, and the difference were significant compared with control group （70d）.Conclusion：The study provides evidence that the effects of lesion of arcuate nucleus firstly lead to the disorder of bone growth,then osteoporosis.The former has an intimate correlation with the hypothalamus-GH- IGF-I axis;the latter has an intimate correlation with the hypothalamus-pituitary-gonad axis.