Defective Bone Microstructure in Hydronephrotic Mice: A Histomorphometric Study in ICR/Mlac‐hydro Mice

Chronic renal impairment can lead to bone deterioration and abnormal bone morphology, but whether hydronephrosis is associated with bone loss remains unclear. Herein, we aimed to use computer‐assisted bone histomorphometric technique to investigate microstructural bone changes in Imprinting Control Region (ICR) mice with a spontaneous mutation that was associated with bilateral nonobstructive hydronephrosis (ICR/Mlac‐hydro). The results showed that 8‐week‐old ICR/Mlac‐hydro mice manifested decreases in trabecular bone number and thickness, and an increased trabecular separation, thereby leading to a reduction in trabecular bone volume compared with the wild‐type mice. Furthermore, histomorphometric parameters related to both bone resorption and formation, that is, eroded surface, osteoclast surface, and osteoblast surface, were much lower in ICR/Mlac‐hydro mice than in the wild type. A decrease in moment of inertia was found in ICR/Mlac‐hydro mice, indicating a decrease in bone strength. In conclusion, ICR/Mlac‐hydro mice exhibited trabecular bone loss, presumably caused by marked decreases in both osteoblast and osteoclast activities, which together reflected abnormally low bone turnover. Thus, this mouse strain appeared to be a valuable model for studying the hydronephrosis‐associated bone disease. Anat Rec, 297:208–214, 2014. © 2013 Wiley Periodicals, Inc.     

Changes in bone mass and body composition after bariatric surgery

Abstract

Aim: To analyze the effects of body weight loss on bone mineral density (BMD) on hip (Hip BMD) and lumbar spine (Lumbar BMD) after six months of bariatric surgery. Bariatric surgery is an effective treatment for morbid obesity. Nonetheless, there are scant data on the effect of weight bearing on bone structure.

Material and methods: Seventeen obese women aged 41.2?±?11.3 yrs. who underwent Roux-en-Y gastric bypass (RYGB) were included. Body composition assessments were performed through dual-energy X-ray absorptiometry immediately before and after 6-months RYGB. Data collected pre- and post-RYGB included total body weight, body mass index (BMI), lean body mass (LM), fat mass (FM) and bone mineral content. The pre- (PRE) and post-operative (POST) results were compared.

Results: Lumbar BMD POST presented a non-significant loss of 1.8% whereas Hip BMD POST showed a significant loss of 17.8%. The analysis demonstrated that BMI and LM PRE explained 26% and 49%, respectively, of Hip BMD PRE variability. In addition, LM POST explained 30% of hip BMD POST variability and was not significant for Lumbar BMD POST.

Conclusions: Obesity and rapid weight loss showed direct influence in Hip BMD after six months of bariatric surgery. However, its effect on the lumbar spine area was smaller due to the higher capacity of the spine to dissipate loads through its curvature.     

强骨康疏胶囊对去卵巢骨质疏松大鼠骨细微结构及骨代谢的影响

目的:观察强骨康疏胶囊对去卵巢骨质疏松大鼠的骨密度、OPG及RANKL蛋白表达、骨组织形态计量学参数及骨组织细微结构的影响。方法:制备去卵巢骨质疏松大鼠模型后,分组:正常对照组、模型空白组、中药低剂量预防组、中药高剂量预防组、雌激素预防组。给药1月后,检测各组股骨骨密度值,显微镜下观察股骨骨小梁的结构变化,并检测骨组织形态计量学参数。采用免疫组织化学染色法检测大鼠股骨OPG及RANKL蛋白表达。结果:模型空白组大鼠股骨骨密度减少,骨小梁厚度、面积、面积百分数均减少,骨小梁间距增大,股骨OPG蛋白平均光密度值显著降低,RANKL蛋白平均光密度值明显增高;雌激素预防组、中药低剂量组、中药高剂量组对上述指标均有明显改善。结论:强骨康疏胶囊能有效提高骨量,维持骨小梁立体空间结构,改善大鼠股骨远端松质骨的显微结构,能够提高骨OPG蛋白表达及抑制RANKL蛋白表达。     

Bone histomorphometry using free and commonly available software

Egan K P, Brennan T A & Pignolo R J
(2012) Histopathology
Bone histomorphometry using free and commonly available software Aims: Histomorphometric analysis is a widely used technique to assess changes in tissue structure and function. Commercially available programs that measure histomorphometric parameters can be cost‐prohibitive. In this study, we compared an inexpensive method of histomorphometry to a current proprietary software program. Methods and results: Image J and Adobe Photoshop^® were used to measure static and kinetic bone histomorphometric parameters. Photomicrographs of Goldner’s trichrome‐stained femurs were used to generate black‐and‐white image masks, representing bone and non‐bone tissue, respectively, in Adobe Photoshop^®. The masks were used to quantify histomorphometric parameters (bone volume, tissue volume, osteoid volume, mineralizing surface and interlabel width) in Image J. The resultant values obtained using Image J and the proprietary software were compared and differences found to be statistically non‐significant. Conclusions: The wide‐ranging use of histomorphometric analysis for assessing the basic morphology of tissue components makes it important to have affordable and accurate measurement options available for a diverse range of applications. Here we have developed and validated an approach to histomorphometry using commonly and freely available software that is comparable to a much more costly, commercially available software program.     

Impairment of rat tooth eruption in pups born to mothers exposed to chronic stress during pregnancy

Objective

Tooth eruption is a multifactorial process in which bone tissue plays a prevailing role. In this study we evaluated the bone overlying the developing tooth germ and the degree of tooth eruption of the first mandibular molar in pups born to mothers subjected to constant light during pregnancy.

Design

Pregnant rats were divided into two groups: mothers chronically exposed to a 12:12 light/light cycle (LL) from day 10 to 20 of pregnancy and controls (C) maintained on a 12:12 h light/dark cycle. Pups from each group were euthanized at the age 3 or 15 days.Buccolingually oriented sections of mandibles were stained with haematoxylin–eosin or for histochemical detection of tartrate resistant acid phosphatase (TRAP). The histomorphometric parameters evaluated were bone volume, number of osteoclasts, TRAP+ bone surface, number of TRAP+ and TRAP− osteoclasts per mm² and degree of tooth eruption (mm).

Results

It was found an increase in bone volume (LL: 58.14 ± 4.24 vs. C: 32.31 ± 2.16; p < 0.01) and a decrease in the number of osteoclasts (LL: 3.5 ± 0.65 vs. C: 8.03 ± 1.31; p < 0.01) and TRAP+ cells (LL: 0.84 ± 0.53 vs. C: 8.59 ± 1.26; p < 0.01) in 3-day-old pups born to LL-exposed mothers. These observations are consistent with the decrease in the degree of tooth eruption observed in 15-day-old experimental pups (LL: −0.605 ± 0.05 vs. C: −0.342 ± 0.02; p < 0.0001).

Conclusion

Our results suggest that chronic constant light applied as a pre-natal stressor impairs the resorptive capacity of osteoclasts involved in the formation of the eruption pathway and consequently the degree of tooth eruption.     

Cortical porosity of the mandible in an osteoporotic sheep model

Objectives: Cortical porosity and thickness of the axial and the appendicular skeleton are predictors of osteoporotic fractures. In the jawbone, however, cortical porosity and thickness may affect the mechanical stability of dental implants. We have shown previously that the jawbone of osteoporotic sheep has impaired trabecular structures, but whether catabolic bone turnover also accounts for the cortical bone porosity remains unknown. Material and methods: We compared mandibular bone from six geriatric sheep subjected to ovariectomy, calcium/vitamin D restriction, and methylprednisolone administration to those of six healthy adult control sheep. Histological ground sections were prepared from the diastema, first and second premolars, and postmolar region. Cortical porosity and thickness were assessed by histomorphometry. Results: Cortical porosity was higher in osteoporotic sheep than in adult controls in the diastema and in the first and second premolar region. In the postmolar region, the difference failed to reach the level of significance. The changes were even more prominent when histomorphometry was restricted to the inner millimeter of the mandibular cortex. In contrast, induction of osteoporosis did not have a discernable effect on cortical thickness. Conclusion: These results demonstrate that cortical porosity of mandibles is more pronounced in geriatric osteoporotic sheep than in adult controls. To cite this article:
Dvorak G, Reich KM, Tangl S, Goldhahn J, Haas R, Gruber R. Cortical porosity of the mandible in an osteoporotic sheep model.
Clin. Oral Impl. Res 22 , 2011; 500–505
doi: 10.1111/j.1600‐0501.2010.02031.x     

不同强度运动对去卵巢大鼠骨量的影响及其机理

以成年SD大鼠去卵巢建立骨质疏松模型,用骨形态计量学方法,研究了8周的大强度和中等强度(分别为20m/min和30m/min,1h/day,5d/week)跑台运动对大鼠胫骨近心干骺端松质骨骨量的影响.结果去卵巢安静组大鼠骨量减少(%Tb.Ar-75%,p＜0.01;Tb.N-74%,p＜0.01),骨形成增加(BFB/BS+115%,BFR/BV+123%,P＜0.01)、骨吸收增加(Oc.No+229%,p＜0.01),为高转换型的骨代谢.中等强度运动的去卵巢大鼠比去卵巢安静大鼠骨形成减少(%L.Pm-42%,BFR/BS-36%,P＜0.05),骨吸收减少(Oc.No-42%,p＜0.05),高转换受到抑制,骨量增加(%Tb.Ar+53%,p＜0.05;Tb.N+69%,p＜0.01),但仍比正常组大鼠骨量降低(%Tb.Ar-61%,p＜0.01).去卵巢后大强度运动与去卵巢安静组大鼠各项指标相比无显著性差异(p＞0.05),与中等强度运动比骨形成增加(BFR/BS+121%,P＜0.01),骨吸收增加(Oc.No+103%,p＜0.05),骨量减少(%Tb.Ar-37%,p＜0.05),仍为高转换型骨代谢.结论大鼠去卵巢后中等强度运动通过抑制高骨转换可减少骨丢失,减轻骨质疏松的程度,大强度运动对减轻骨质疏松的程度无作用.     

三种膳食结构对去卵巢大鼠骨量和骨结构的影响

目的 比较不同膳食结构对去卵巢大鼠（OVX）骨量和骨结构的影响。方法 30只去卵巢大鼠随机分为3组,分别以基础、高脂和黄豆饲料喂养3个月。每周称体重一次,结算各组大鼠每天的摄食量。3个月后,采血测血清血脂水平、血钙、血磷和雌二醇;双能X线骨密度仪测定实验前、后大鼠全身、脊柱和股骨骨密度;取一侧股骨制备脱钙骨切片,进行骨形态学观察和骨计量学测定。结果 1、各组大鼠每天食物摄入量、血钙和血磷无统计学差异。2、黄豆饲料组大鼠体重最小(P<0.05);血清E2水平最高(P<0.05);全身、股骨和脊柱BMD均最高(P<0.05);骨小梁数量最多、骨小梁面积和厚度均最大(P<0.05)。而高脂饲料组大鼠体重最大(P<0.05);TG和LDL水平最高,HDL最低 (P<0.05);全身、股骨和脊柱BMD均最低(P<0.05),高脂饲料与基础饲料相比,骨小梁数量无差异,但骨小梁面积和厚度较大(P<0.05)。结论 从绝经后骨质疏松预防角度来说,富含黄豆的饮食较高脂饮食是一种较好的膳食结构;后者可能加速了女性的骨丢失。     

Infrared spectroscopy indicates altered bone turnover and remodeling activity in renal osteodystrophy

Renal osteodystrophy alters metabolic activity and remodeling rate of bone and also may lead to different bone composition. The objective of this study was to characterize the composition of bone in high‐turnover renal osteodystrophy patients by means of Fourier transform infrared spectroscopic imaging (FTIRI). Iliac crest biopsies from healthy bone (n = 11) and patients with renal osteodystrophy (ROD, n = 11) were used in this study. The ROD samples were from patients with hyperparathyroid disease. By using FTIRI, phosphate‐to‐amide I ratio (mineral‐to‐matrix ratio), carbonate‐to‐phosphate ratio, and carbonate‐to‐amide I ratio (turnover rate/remodeling activity), as well as the collagen cross‐link ratio (collagen maturity), were quantified. Histomorphometric analyses were conducted for comparison. The ROD samples showed significantly lower carbonate‐to‐phosphate (p < .01) and carbonate‐to‐amide I (p < .001) ratios. The spatial variation across the trabeculae highlighted a significantly lower degree of mineralization (p < .05) at the edges of the trabeculae in the ROD samples than in normal bone. Statistically significant linear correlations were found between histomorphometric parameters related to bone‐remodeling activity and number of bone cells and FTIRI‐calculated parameters based on carbonate‐to‐phosphate and carbonate‐to‐amide I ratios. Hence the results suggested that FTIRI parameters related to carbonate may be indicative of turnover and remodeling rate of bone. © 2010 American Society for Bone and Mineral Research