This research is an independent study and did not receive any funding.

The protocol adheres to the ethical guidelines set by the Institutional Animal Care and Use Committee (IACUC) at Beijing University of Chinese Medicine, Protocol number BUCM-4-2022062001-2109. The protocol uses Sprague Dawley (SD) rats (SCXK(Jing)2019-0008), aged 8-10 weeks and weighing 200 g-250 g.
1. Adaptation training
<ol>
	<li>Albino rats generally have a visual range of less than 60 cm15. During the modeling process, place the rats in opaque cag...

Elastic Tape Rat Model of Steroid-Induced Femoral Head Osteonecrosis Enhancement

<ol>
	<li>Konarski, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Avascular+necrosis+of+femoral+head-overview+and+current+state+of+the+art.">Avascular necrosis of femoral head-overview and current state of the art.</a> Inl J Environ Res Public Health. 19 (12), 7348 (2022).</li><li>Tan, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiological+study+based+on+China+osteonecrosis+of+the+femoral+head+database.">Epidemiological study based on China osteonecrosis of the femoral head database.</a> Ortho Surg. 13 (1), 153-160 (2020).</li><li>Algarni, A. D., Al Moallem, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+and+radiological+outcomes+of+extracorporeal+shock+wave+therapy+in+early-stage+femoral+head+osteonecrosis.">Clinical and radiological outcomes of extracorporeal shock wave therapy in early-stage femoral head osteonecrosis.</a> Adv Ortho. 2018, 7410246 (2018).</li><li>Huang, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chinese+herbal+Huo-Gu+formula+for+the+treatment+of+steroid-associated+osteonecrosis+of+femoral+head:+A+14-year+follow-up+of+convalescent+SARS+patients.">Chinese herbal Huo-Gu formula for the treatment of steroid-associated osteonecrosis of femoral head: A 14-year follow-up of convalescent SARS patients.</a> J Ortho Transl. 23, 122-131 (2020).</li><li>Tomaru, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concentrated+autologous+bone+marrow+aspirate+transplantation+versus+conservative+treatment+for+corticosteroid-associated+osteonecrosis+of+the+femoral+head+in+systemic+lupus+erythematosus.">Concentrated autologous bone marrow aspirate transplantation versus conservative treatment for corticosteroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus.</a> J Rural Med. 16 (1), 1-7 (2021).</li><li>Wu, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+analysis+of+different+morphology+of+the+necrotic-viable+interface+in+osteonecrosis+of+the+femoral+head.">Prognostic analysis of different morphology of the necrotic-viable interface in osteonecrosis of the femoral head.</a> Int Ortho. 42 (1), 133-139 (2018).</li><li>Troy, K. L. R., Lundberg, H. J., Conzemius, M. G., Brown, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Habitual+hip+joint+activity+level+of+the+penned+EMU+(Dromaius+novaehollandie).">Habitual hip joint activity level of the penned EMU (Dromaius novaehollandie).</a> Iowa Ortho J. 27, 17 (2007).</li><li>Jiang, W., Wang, P., Wan, Y., Xin, D., Fan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+establishing+an+ostrich+model+of+femoral+head+osteonecrosis+and+collapse.">A simple method for establishing an ostrich model of femoral head osteonecrosis and collapse.</a> J Ortho Surg Res. 10, 1-10 (2015).</li><li>Murata, M., Kumagai, K., Miyata, N., Osaki, M., Shindo, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteonecrosis+in+stroke-prone+spontaneously+hypertensive+rats:+effect+of+glucocorticoid.">Osteonecrosis in stroke-prone spontaneously hypertensive rats: effect of glucocorticoid.</a> J Ortho Sci. 12 (3), 289-295 (2007).</li><li>Drescher, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+constriction+of+supplying+arteries-A+mechanism+of+femoral+head+Necrosis+in+Wistar+rats.">Enhanced constriction of supplying arteries-A mechanism of femoral head Necrosis in Wistar rats.</a> Ann Anat. 192 (1), 58-61 (2010).</li><li>Friedman, M. A., Zhang, Y., Wayne, J. S., Farber, C. R., Donahue, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+limb+immobilization+model+for+bone+loss+from+unloading.">Single limb immobilization model for bone loss from unloading.</a> J Biomech. 83, 181-189 (2019).</li><li>Gadomski, B. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+gravity+unloading+inhibits+bone+healing+responses+in+a+large+animal+model.">Partial gravity unloading inhibits bone healing responses in a large animal model.</a> J Biomech. 47 (12), 2836-2842 (2014).</li><li>Peng, P., Nie, Z., Sun, F., Peng, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucocorticoids+induce+femoral+head+necrosis+in+rats+through+the+ROS/JNK/c-Jun+pathway.">Glucocorticoids induce femoral head necrosis in rats through the ROS/JNK/c-Jun pathway.</a> FEBS Open bio. 11 (1), 312-321 (2021).</li><li>Yan, Y. Q., Pang, Q. J., Xu, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+erythropoietin+for+precaution+of+steroid-induced+femoral+head+necrosis+in+rats.">Effects of erythropoietin for precaution of steroid-induced femoral head necrosis in rats.</a> BMC Musculoskel Dis. 19, 1-7 (2018).</li><li>Dean, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+rats+short-sighted?+Effects+of+stimulus+distance+and+size+on+visual+detection.">Are rats short-sighted? Effects of stimulus distance and size on visual detection.</a> Quat J Exp Psychol Sec B. 33 (2), 69-76 (1981).</li><li>Fu, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proper+mechanical+stress+promotes+femoral+head+recovery+from+steroid-induced+osteonecrosis+in+rats+through+the+OPG/RANK/RANKL+system.">Proper mechanical stress promotes femoral head recovery from steroid-induced osteonecrosis in rats through the OPG/RANK/RANKL system.</a> BMC Musculoskel Dis. 21, 281 (2020).</li><li>Wan, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+glucocorticoids+on+miRNA+expression+spectrum+of+rat+femoral+head+microcirculation+endothelial+cells.">Effect of glucocorticoids on miRNA expression spectrum of rat femoral head microcirculation endothelial cells.</a> Gene. 651, 126-133 (2018).</li><li>Alahmari, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+Kinesio+taping+on+cervical+proprioception+in+athletes+with+mechanical+neck+pain-a+placebo-controlled+trial.">The effect of Kinesio taping on cervical proprioception in athletes with mechanical neck pain-a placebo-controlled trial.</a> BMC Musculoskel Dis. 21, 1-9 (2020).</li><li>Shidara, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain-specific+differences+in+the+development+of+bone+loss+and+incidence+of+osteonecrosis+following+glucocorticoid+treatment+in+two+different+mouse+strains.">Strain-specific differences in the development of bone loss and incidence of osteonecrosis following glucocorticoid treatment in two different mouse strains.</a> J Ortho Transl. 16, 91-101 (2019).</li><li>Lv, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+model+of+traumatic+femoral+head+necrosis+in+rats+developed+by+microsurgical+technique.">A novel model of traumatic femoral head necrosis in rats developed by microsurgical technique.</a> BMC Musculoskel Dis. 23 (1), 374 (2022).</li><li>Yu, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Icariin+promotes+angiogenesis+in+glucocorticoid-induced+osteonecrosis+of+femoral+heads:+In+vitro+and+in+vivo+studies.">Icariin promotes angiogenesis in glucocorticoid-induced osteonecrosis of femoral heads: In vitro and in vivo studies.</a> J Cell Mol Med. 23 (11), 7320-7330 (2019).</li><li>Kim, H. K., Morgan Bagley, S., Kostenuik, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RANKL+inhibition:+a+novel+strategy+to+decrease+femoral+head+deformity+after+ischemic+osteonecrosis.">RANKL inhibition: a novel strategy to decrease femoral head deformity after ischemic osteonecrosis.</a> J Bone Mine Res. 21 (12), 1946-1954 (2006).</li><li>Weinstein, R. S., Jilka, R. L., Parfitt, A. M., Manolagas, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+osteoblastogenesis+and+promotion+of+apoptosis+of+osteoblasts+and+osteocytes+by+glucocorticoids.+Potential+mechanisms+of+their+deleterious+effects+on+bone.">Inhibition of osteoblastogenesis and promotion of apoptosis of osteoblasts and osteocytes by glucocorticoids. Potential mechanisms of their deleterious effects on bone.</a> J Clin Invest. 102 (2), 274-282 (1998).</li><li>Kapfer, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The effects of hyperbaric exposure on bone cell activity in the rat: implications for the pathogenesis of dysbaric osteonecrosis. , (1995).</li><li>Jiang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Puerarin+facilitates+osteogenesis+in+steroid-induced+necrosis+of+rabbit+femoral+head+and+osteogenesis+of+steroid-induced+osteocytes+via+miR-34a+upregulation.">Puerarin facilitates osteogenesis in steroid-induced necrosis of rabbit femoral head and osteogenesis of steroid-induced osteocytes via miR-34a upregulation.</a> Cytokine. 143, 155512 (2021).</li><li>Peng, P., Nie, Z., Sun, F., Peng, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucocorticoids+induce+femoral+head+necrosis+in+rats+through+the+ROS/JNK/c-Jun+pathway.">Glucocorticoids induce femoral head necrosis in rats through the ROS/JNK/c-Jun pathway.</a> FEBS Open bio. 11 (1), 312-321 (2021).</li><li>Chen, C. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucocorticoid-induced+loss+of+beneficial+gut+bacterial+extracellular+vesicles+is+associated+with+the+pathogenesis+of+osteonecrosis.">Glucocorticoid-induced loss of beneficial gut bacterial extracellular vesicles is associated with the pathogenesis of osteonecrosis.</a> Sci Adv. 8 (15), 8335 (2022).</li><li>Gorios Filho, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+model+study+of+ischemic+necrosis+induction+of+the+growing+femoral+head.">Experimental model study of ischemic necrosis induction of the growing femoral head.</a> Acta Ortop Bras. 30 (2), e247996 (2022).</li><li>Wilson, F. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+field+study+of+histologic+and+bacteriologic+characterization+of+femoral+head+separation+and+femoral+head+necrosis.">A field study of histologic and bacteriologic characterization of femoral head separation and femoral head necrosis.</a> Avian Dis. 64 (4), 571-581 (2020).</li><li>Fan, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparisons+of+emu+necrotic+femoral+head+micro+structure+repaired+in+two+different+methods.">Comparisons of emu necrotic femoral head micro structure repaired in two different methods.</a> Acta Acad Med Sinicae. 38 (1), 16-21 (2016).</li><li>Naito, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Femoral+head+necrosis+and+osteopenia+in+stroke-prone+spontaneously+hypertensive+rats+(SHRSPs).">Femoral head necrosis and osteopenia in stroke-prone spontaneously hypertensive rats (SHRSPs).</a> Bone. 14 (5), 745-753 (1993).</li><li>Omokawa, S., Tamai, S., Ohneda, Y., Mizumoto, S., Yamamoto, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+histopathological+study+on+the+femoral+head+necrosis+in+spontaneously+hypertensive+rats+(SHR).">A histopathological study on the femoral head necrosis in spontaneously hypertensive rats (SHR).</a> Nihon Seikeigeka Gakkai Zasshi. 66 (1), 69-82 (1992).</li></ol>

The author declares no conflicts of interest, affiliations, or collaborations that could potentially influence the objectivity or outcomes of this research.

Currently, various animals, such as rabbits25, rats26, mice27, pigs28, broilers29, ostriches8, and emus30 can be used to establish models of femoral head necrosis. Among them, rats, mice, and rabbits are the most commonly used species. The rat, as a model for femoral head necrosis, offers numerous advantages. Rats are easy to feed and breed, grow rapidly, ...

The administration of glucocorticoids is the most common risk factor for non-traumatic osteonecrosis of the femoral head (ONFH)1. Numerous pieces of evidence suggest that, in addition to glucocorticoids, the pressure load on the hip joint in patients is also associated with the occurrence of ONFH. Factors such as body weight and physical labor intensity are recognized as risk factors for ONFH2. Multiple clinical studies have demonstrated a close relationship between hip joint loading conditions and the timing and incidence of joint replacement3,4,5,6. Therefore, establishing a model that reflects the relationship between load bearing and steroid-induced osteonecrosis of the femoral head (SONFH) is important for a comprehensive investigation of this condition.
Large bipedal birds, such as ostriches and emus, serve as good models to simulate hip joint stress, resembling human leg loads7,8. However, maintaining large bird species is challenging, and the associated research costs are high. Spontaneously hypertensive rat models9,10 can exhibit higher rates of ONFH, but the compartment pressure load in the marrow generated by spontaneous hypertension differs significantly from mechanical pressure and is unsuitable for studying the impact of mechanical pressure on SONFH.
Small animal models are commonly used in research on SONFH. However, quadrupedal reptiles have lower hip joint stress, and their hip models cannot simulate the biomechanical environment of human hip joints during bipedal walking. Single limb immobilization models11 and partial unloading models12 are common, but both reduce limb loading. As humans are bipedal organisms with substantial lower limb loads while standing and walking, reducing the load in these models diminishes the connection between animal models and human diseases.
This study aims to establish a simple and cost-effective model for weight-bearing training to investigate the impact of weight-bearing training on steroid-induced osteonecrosis of the femoral head in rats. Currently, rat models have been used to study steroid-induced osteonecrosis of the femoral head13,14, but there is still no model that can provide long-term, safe fixation with minimal disruption to movement, which is also relatively simple and inexpensive. In this study, a high-adhesive fixation material is applied, adopting tension-free fixation, which maintains the rats&#39; mobility and reduces the suffering and even death caused by improper fixation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>15ml centrifuge tube</td>
			<td>Corning,USA</td>
			<td>430791</td>
			<td></td>
		</tr>
		<tr>
			<td>5mm stainless steel bead</td>
			<td>Gelisen,China</td>
			<td>5mm</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Merck KGaA, Germany</td>
			<td>64-19-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Anhydrous alcohol</td>
			<td>Merck KGaA, Germany</td>
			<td>64-17-5</td>
			<td></td>
		</tr>
		<tr>
			<td>clay</td>
			<td>Mincai stationery,China</td>
			<td>102</td>
			<td></td>
		</tr>
		<tr>
			<td>Coverslip</td>
			<td>Servicebio,China</td>
			<td>WMWD-1818</td>
			<td></td>
		</tr>
		<tr>
			<td>Flat pressure bottle 10ml</td>
			<td>BEHNCKE,China</td>
			<td>MD10ml</td>
			<td></td>
		</tr>
		<tr>
			<td>Formic acid</td>
			<td>Macklin Biochemical&#160;,China</td>
			<td>64-18-6</td>
			<td></td>
		</tr>
		<tr>
			<td>HE staining kit</td>
			<td>Solarbio,China</td>
			<td>G1120</td>
			<td></td>
		</tr>
		<tr>
			<td>HistoCore AUTOCUT</td>
			<td>Leica, Germany</td>
			<td>149AUTO00C1</td>
			<td></td>
		</tr>
		<tr>
			<td>Kinesio tape (elastic therapeutic tape)</td>
			<td>Fuluo medicine,China</td>
			<td>CL1819</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipopolysaccharide</td>
			<td>Solarbio,China</td>
			<td>L8880</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipopolysaccharides (LPS)</td>
			<td>Selleck,USA</td>
			<td>S7850&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Manual carbon dioxide euthanasia box</td>
			<td>Yuyan,China</td>
			<td>LC-500-S1</td>
			<td></td>
		</tr>
		<tr>
			<td>Methylprednisolone&#160;sodium succinate,MPS</td>
			<td>AbMole,China</td>
			<td>M25573</td>
			<td></td>
		</tr>
		<tr>
			<td>MicroCT</td>
			<td>&#160;Hiscan,China</td>
			<td>&#160;Hiscan VM Pro</td>
			<td></td>
		</tr>
		<tr>
			<td>Neutral resin</td>
			<td>Beijing Zhongshan Golden Bridge Biotechnology l&#160;,China</td>
			<td>ZLI-9555</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraffin</td>
			<td>Servicebio,China</td>
			<td>WGHB-319213129</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Servicebio,China</td>
			<td>G1101-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Macklin Biochemical&#160;,China</td>
			<td>&#160;7447-40-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Slide</td>
			<td>Servicebio,China</td>
			<td>WG6012</td>
			<td></td>
		</tr>
		<tr>
			<td>Treadmill for Rats and&#160; mice</td>
			<td>Litc Life Science,USA</td>
			<td>801</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Macklin Biochemical&#160;,China</td>
			<td>&#160;1330-20-7</td>
			<td></td>
		</tr>
	</tbody>
</table>

tension-free weight-bearing model of steroid-induced osteonecrosis of femoral head in rats

Unlike humans, rats are animals that walk on all fours, while humans are bipedal animals that stand, and the hips are subjected to tremendous pressure when walking and standing. In rat steroid-induced femoral head necrosis models, the biomechanical characteristics of the human hip under higher pressure often need to be simulated. Some scholars try to emulate the state of human hip pressure by making rats bear a certain weight, but fixing the weight-bearing object on the rat is tough. Rats can easily break free of immobilization, and sticking the weight on the rats with adhesive tape will cause the rats to suffocate or die from intestinal obstruction. Our research group used elastic therapeutic tape to perform tension-free immobilization of weight-bearing objects in rats so that the rats could breathe freely and not break away from the immobilization under weight-bearing conditions. Compared to the usual steroid-induced femoral head necrosis rat model, we found that this weight-bearing intervention can aggravate the progression of femoral head necrosis in rats.

Author Spotlight: Developing a Rat Model for Weight-Bearing Intervention to Investigate Osteonecrosis of the Femoral Head

Tension-Free Weight-Bearing Model of Steroid-Induced Osteonecrosis of Femoral Head in Rats

We primarily developed the rat model for weight-bearing interventions to investigate the efforts of weight-bearing exercise on osteonecrosis of the femoral head. Currently, most of the models are non-weight-bearing models. However, the progressions of the osteonecrosis in the femoral head may be associated with weight-bearing exercises.It's actually very difficult to secure weights onto rats as most method severe restricted their moment, thereby failing to achieve their purpose of weight-bearing exercises.

Histopathology analysis 
Hematoxylin and eosin staining revealed that in the Control group and Control+Load group, bone trabeculae were intact and arranged regularly. Blood vessel endothelial cells were present in bone dimples, and the cell morphology appeared plump. In contrast, the Model group and Model+Load group exhibited fractured and disordered bone trabeculae, along with a significantly higher number of empty lacunae. The Model+Load group had more empty lacunae compared to the Model group. In...

The protocol shows building a simple and cost-effective rat weight-bearing training model for steroid-induced osteonecrosis of the femoral head using elastic therapeutic tape.

Unlike humans, rats are animals that walk on all fours, while humans are bipedal animals that stand, and the hips are subjected to tremendous pressure ...

tension-free-weight-bearing-model-steroid-induced-osteonecrosis

Research

JoVE Journal

Medicine

Adaptation Training and Measurement of Weight-Bearing Capacity of Albino Rats for Studying Femoral Head Necrosis Progression

To begin adaptation training. First, place the rats in opaque cages. Keep them as far away as possible from non-model rats, ensuring the other rats are outside the maximum visual range.Turn on the power and set the treadmill to 10 meters per minute with a zero degree incline. Place the rats on the treadmill and ensure the movements are as gentle as possible to avoid stress. After a 15-minute training, clean up the feces and urine left by the rats.Spray the treadmill with alcohol to eliminate the animal odor. Continue training all animals for a week. Prepare two test tubes, a hook and a loop fastener approximately 80 centimeters long.Place steel balls into the test tubes, ensuring that the initial combined weight of the test tubes, the hook and the loop fastener is 150 grams. Prepare test tubes with different total weights in 10-gram increments with the maximum weight being 350 grams. Now with gloved hands, hold a rat.Wrap the hook and loop fastener of a tube on the back of the rat about one centimeter from the midline. Change the tube from lower to higher weight until the rat is unable to stand when prodded or the experimenter leaves. Reduce the weight by 10 grams to allow the rat to stand.This weight represents the rat's maximum weight-bearing capacity. To prepare the weight load, first, use a one to 1.5 meter long elastic therapeutic tape to secure the fixation objects. With clay, adjust the weight of the test tubes to reduce the swinging of the load.After weighing the tubes and the fixation objects, add an appropriate amount of clay into the test tubes to adjust them to the target weight. Now use a glass stirring rod to evenly spread the clay inside the test tubes. Clay concentrated at one end of the test tube, may cause it to detach easily during training.Adjust the total weight of the adjusted test tubes and clay at 50%of the rat's maximum weight-bearing capacity.

Tension-Free Weight-Bearing Immobilization in Steroid-Induced Osteonecrosis of the Femoral Head Albino Rat Models

To establish a steroid induced osteonecrosis of the femoral head, or SONHF model, use an albino rat. Intraperitoneally inject lipopolysaccharide into the midline of the rat's abdomen every 24 hours. After the last lipopolysaccharide injection, inject methylprednisolone into alternate unilateral gluteal muscle every 24 hours after regular feeding.Next, mark the rat's back midline at one to two centimeters on both sides as a reference point for the weight load. Make sure that the marks are appropriately positioned to prevent the rat from tipping or hindering movement during treadmill training. Now, with the help of another investigator, hold the rat with gloved hands.Place one hand under the rat's armpit to secure the forelimb and jaw. Then use the other hand to secure the hind limbs and tail. Stick the elastic therapeutic tape to the test tube without applying tension to secure the load on the rat's back.Ask the second investigator to fix the test tube to the rat's back parallel to the rat's spine. To minimize the suffering of the rat, perform fixation without applying tension. Stick the test tube with adjusted weight onto the elastic therapeutic tape.Then wrap the test tube around the rat's body using a tension-free technique. Place the rat in an open space or a single cage, and monitor its breathing and direction. Promptly, release the rat if it breathes rapidly or opens its mouth.Ideal immobilization should allow the rat to move freely and perform activities like drinking, lifting forelimbs, and feeding. Release and re-immobilize after 20 minutes if immobilization is unsatisfactory. Next, turn on a treadmill and set the speed to one meter per minute with a zero-degree incline.Gently transfer the rat onto the treadmill and begin the timer. If the rat cannot complete the 30-minute training, place it in a cage for a 10-minute rest without removing the fixation. After the training, clean up the feces and urine left by the rats and spray alcohol to eliminate the animal odor.Handle the animals as gently as possible to prevent animals from vocalizing and causing traumatic stress to other rats. Immediately release the rat from fixation after the completion of training.

231 Views.  Beijing University of Chinese Medicine.  The protocol shows building a simple and cost-effective rat weight-bearing training model for steroid-induced osteonecrosis of the femoral head using elastic therapeutic tape.

Elastic Tape Rat Model of Steroid-Induced Femoral Head Osteonecrosis Enhancement

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