损毁弓状核对幼年大鼠骨生长发育的影响

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.

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

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.