糖皮质激素抑制幼鼠骨骼生长发育的实验研究

Glucocorticoid inhibit immature rat＇s bone growth and development of experimental research

目的探讨在地塞米松干预下骨形成标志物骨钙蛋白（OC）、骨碱性磷酸酶（BAKP）及Ⅰ型前胶原氨基端前肽（PINP）与骨骼纵向生长的关系。方法四周龄雄性SD大鼠33只，按随机数字表法分配为实验组（18只）和对照组（15只）。两组大鼠均标准鼠粮喂养，实验组腹腔注射地塞米松200 μg/100 g，对照组腹腔注射生理盐水2 ml/d，连用10 d。末次给药后次日8∶00，根据体重予以10%水合氯醛腹腔注射麻醉，去头采血约3 ml，分离血清，保存于－80℃冰箱待测。分离胫骨、测量胫骨长。制备胫骨生长板组织切片，以胫骨长反映骨骼纵向生长情况，通过HE染色方法显示生长板软骨细胞形态，测量生长板厚度。采用ELISA方法检测大鼠OC、BAKP和PINP值。结果实验组SD大鼠胫骨长度（P＝0.000）、生长板厚度（P＝0.001）均小于对照组。二组血清生化标志物OC、BAKP、PINP比较差异无统计学意义（P〉0.05）。对照组OC与胫骨长度呈正相关（r＝0.454，P＝0.008），实验组PINP与OC呈正相关（r＝0.521，P＝0.026）。结论胫骨长度是反映大鼠骨骼纵向生长的有效指标，地塞米松能够抑制童龄SD大鼠胫骨生长，对生长发育阶段的SD大鼠成骨细胞功能（OC、BAKP和PINP）抑制作用不明显。

Objective To explore bone formation markers in dexamethasone intervention osteocalcin（ OC）, bone alkaline phosphatase （BAKP）, and type I original amino terminal propeptide （PINP） relationship with bone longitudinal growth. Methods The selected thirty-three 4-week-old male Sprague- Dawley （SD） rats were randomly divided into two groups： the dexamethasone group （n = 18 ） and the control group （n = 15 ）. The rats in the dexamethasone group received dexamethasone （200 μg/100 g） by intraperitoneal injection for 10 days. The rats in the control group received matching volume sodium chloride solution. All rats were weighed everyday. The rats were killed by using 10% chloral hydration at 8 AM of 11 th day. The length of tibiae was measured. The proximal tibiae were excised, fixed and decalcified. After paraffin embedded, sections in 5 μm thick were cut. The growth plate sections were stained by haematoxylin-eosin （HE） histochemistry method. Total height of growth plate was measured. The rats decaptitating and the blood were collected. Serum was separated and stored in - 80 ℃ refrigerator for analysis. Enzyme -linked immuno sorbent assay （ELISA） method was used to detect the rat OC, BAKP and PINP values. Results The length of growth plate and tibiae of dexamethasone group were significantly decreased contrast the control group ： the length of growth plate （ P = 0. 001 ）, and the length of tibiae （ P = 0. 000 ）. There were no significant differences between two groups of the value of OC, BAKP and PINP： OC （ P = 0. 056）, BAKP （P =0. 122）, and PINP （P =0. 169）. There was positive correlation between the serum OC and the length of tibiae （r =0. 454,P =0.08） in control group, the PINP and OC （r =0. 521 ,P =0. 026） in dexamethasone group. Conclusions Glucocorticoid inhibit the longitudinal bone growth, to the osteoblasts （OC, BAKP and PINP） of growing rats is not obvious.