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不同剂量和作用时间地塞米松对大鼠骨密度和成骨细胞作用的研究 |
Effect of dexamethasone at different doses and courses on bone mineral density and osteoblastsin rats |
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DOI:10.3969/j.issn.1006-7108.2018.06.012 |
中文关键词: 地塞米松 骨密度 成骨细胞 骨形成 |
英文关键词:Dex Bone mineral density Osteoblast Bone formation |
基金项目:国家自然科学基金(81260142) |
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中文摘要: |
目的 观察地塞米松(Dex)不同剂量及不同作用时间对大鼠骨量、成骨细胞的影响。方法 120 只3 月龄SD 雌性大
鼠,随机分对照组(生理盐水)、小剂量组(地塞米松1 mg/ kg)、中剂量组(地塞米松2?? 5 mg/ kg)、高剂量组(地塞米松5 mg/
kg),每组30 只,2 次/ 周肌内注射,分别干预4 w、9 w、12 w。给药前及干预后采用双能X 线骨密度仪测大鼠全身骨密度
(BMD),免疫组化法检测骨组织碱性磷酸酶(ALP)、I 型胶原蛋白表达。从新生SD 大鼠颅骨体外分离培养成骨细胞, 随机分
为5 组:空白对照组、5 ×10 -8 mol/ L Dex 组、5 ×10 -7 mol/ L Dex 组、5 ×10 -6 mol/ L Dex 组、5 ×10 -5 mol/ L Dex 组,分别培养12
h、24 h、48 h 后,采用CCK8 法检测成骨细胞增殖,采用RT? PCR 检测成骨细胞ALP mRNA、I 型胶原mRNA 表达。结果 (1)
干预4 w,不同剂量Dex 组大鼠的骨密度与对照组无差异(P >0?? 05)。干预9 w,不同剂量Dex 组大鼠的骨密度均低于对照组
(P <0?? 05),高剂量组大鼠骨密度低于小剂量组(P < 0?? 05);干预12 w,不同剂量Dex 组大鼠的骨密度均低于对照组(P <
0?? 05),且随着剂量的增加,大鼠的骨密度逐渐降低。(2)干预4 w,ALP、I 型胶原蛋白表达与对照组无差异(P >0?? 05);干预9
w,中剂量和高剂量组大鼠骨组织I 型胶原蛋白表达均低于对照组(P <0?? 05),不同剂量组大鼠骨组织ALP 蛋白表达均低于对
照组(P <0?? 05);干预12 w,大鼠骨组织ALP、I 型胶原蛋白表达均低于对照组(P < 0?? 05);随着Dex 剂量的增加,大鼠骨组织
ALP 及I 型胶原蛋白表达逐渐降低。(3)体外分离培养成骨细胞干预12 h, 5 ×10 -6 mol/ L Dex 和5 ×10 -5 mol/ L Dex 均抑制
成骨细胞增殖(P <0?? 05),5 ×10 -5 mol/ L Dex 组成骨细胞的ALP、I 型胶原mRNA 表达减少(P <0?? 05);干预24 h 及48 h,不同
浓度Dex 均明显抑制成骨细胞增殖(P < 0?? 05),ALP、I 型胶原mRNA 表达明显减少(P < 0?? 05),呈剂量和时间依赖性。
结论 地塞米松可能通过抑制成骨细胞的增殖及骨形成,导致SD 大鼠骨密度降低。 |
英文摘要: |
Objective To investigate the effect of dexamethasone (Dex) on rat bone mass and osteoblasts at different dose and
time. Methods A total of 120 3?month?old SD rats were randomly divided into control group (Cont, saline), low?dose Dex
group (LDG, 1 mg / kg), medium?dose Dex group (MDG, 2?? 5 mg / kg) and high?dose Dex group (HDG, 5 mg / kg), with 30 rats
in each group. Dex was injected intramuscularly twice a week for 4, 9, and 12 weeks. BMD was measured using dual energy X ray
absorptiometry. The protein expression of ALP and type I collagen in bone tissue was measured with immunohistochemistry. The
osteoblasts were collected fromol / L the calvaria of newborn SD rats and cultured. They were then randomly divided into 5 groups:
blank group, 5 ×10 -8 mol / L group, 5 ×10 -7 mol / L group, 5 ×10 -6 mol / L group, and 5 ×10 -5 mol / L group. Cells were cultured
for 12, 24, or 48 h. Cell proliferation was measured with CCK8 method . The expressions of ALP and type I collagen mRNA were
measured with RT?PCR. Results (1) After 4?week intervention, BMD in different doses of Dex groups were not different
compared with control group (P >0?? 05). After 9?week treatment, BMD in different doses of Dex groups were lower than that ofcontrol group (P < 0?? 05). BMD was significantly lower in HDG groups than those in LDG group (P < 0?? 05). After 12?week
intervention, BMD was significantly lower in Dex groups than in control group in a dose?dependent manner. (2) The expressions of
ALP and type I collagen protein were not different between Dex groups and control group in 4 weeks (P >0?? 05). The expressions
of ALP and type I collagen protein were lower in MDG and HDG groups than in control group in 9 and 12 weeks (P <0?? 05). (3)
At 12 h, the proliferation of osteoblasts at the concentrations of 5 × 10 -6 mol / L and 5 × 10 -5 mol / L groups were inhibited (P <
0?? 05). The expressions of ALP and type I collagen mRNA in 5 ×10 -5 mol / L group were lower than in blank group (P <0?? 05). At
24 h and 48 h, the proliferation and expression of ALP and type I collagen mRNA in different concentrations of Dex groups were
lower than those in blank group (P <0?? 05). Conclusion Dex inhibits osteoblast proliferation and bone formation, leading to a
decrease of BMD in rats. |
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