骨组织形态计量学观察低钙和低蛋白饮食对大鼠骨骼的影响

Bone Histomorphometric Analysis of the Effect of Low Calcium and/or Low Protein Diet on the Skeleton of the Male Rats

目的观察低蛋白和低钙饮食所致大鼠骨骼的变化,并与对照组进行比较。方法30只3个月龄SD雄性大鼠,随机分为正常年龄对照组(control)、极低钙组(VLCD,Ca0.01%)、低钙组(LCD、Ca0.3%)、低蛋白组(LPD、Pr8%)、混合组(Ca0.01%+Pr8%)。3个月后取大鼠左侧胫骨近心端,行骨组织形态计量学分析。结果与对照组相比,VLCD和LCD组大鼠骨量均减少,骨小梁面积百分率(%Tb.Ar)分别减少57%(P<0.01)和40%(P<0.05),代表骨形成指标如荧光周长百分数(L.Pm%)、矿化沉积率(MAR)、骨形成率(BFR/BV)有增加的趋势。VLCD组骨吸收参数如毫米破骨细胞数量(N.OC/Tb.Pm)增加63%(P<0.05),呈现骨高转化的改变。LPD组大鼠%Tb.Ar减少57%(P<0.01),骨形成减少,骨吸收增加不明显,呈低骨转化趋势。混合作用组骨量比单纯低钙、低蛋白组显著降低,动态参数与VLCD组相比呈更明显的骨高转化的改变,与LPD的低转化改变明显不同。结论低钙饮食可使骨量减少并伴有骨转换增加,而低蛋白、低钙饮食使骨转化增加更明显,骨量降到更低。

Objective To study the effects of low calcium and/or low protein diet on t he skeleton of the male rats by bone histomorphometry.Methods Thirty three-month-old Sprague-Dawley male rats were randomized into five groups:the control grou p(0.7%Ca,20%Pr ),the very low calcium diet group(VLCD,0.01%Ca ),the low calcium diet group (LCD,0.3%Ca),th e low protein diet group (LPD,8%P r)and the combination of VLCD and LPD group.After90days,all ra ts were killed and the left tibial was harvested for histomorphometrical evaluat ions.Results The VLCD and the LCD group lost57%(P<0.01)and40%(P< 0.05)of cancellous bone compared with that of the control group by3months ,respectively.The dynamic data in the VLCD group showed bone formation indices such as percent labeled perimeter (L.Pm%),mineral apposition rate(MAR)a nd bone formation rate (BFR/BV)increased without significance.Bone resorptio n indices such as osteoclast number per mm(N.Oc /Tb.Pm)in the VLCD group inc reased63%(P<0.05).The effect in the LCD group was lesser than that in the VLCD group.The LPD group also lost57%of bone mass with no significantly decreased bone formation and increased bone resorption.The combination of VLCD and LPD had the lowest bone mass in all groups and its dynamic data showed an i ncreased bone turnover compared with VLCD.Conclusions The results indicated that bone lo ss was associated with increased bone turnover in low calcium dietary rats and i mpressed bone formation in low protein dietary ones.The combination of both led to more bone loss with higher bone turnover.