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Autophagy mediated CoCrMo particle-induced peri-implant osteolysis by promoting osteoblast apoptosis.

Wang Z, Liu N, Liu K, Zhou G, Gan J, Wang Z, Shi T, He W, Wang L, Guo T, Bao N, Wang R, Huang Z, Chen J, Dong L, Zhao J, Zhang J - Autophagy (2015)

Bottom Line: Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts.Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models.Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model.

View Article: PubMed Central - PubMed

Affiliation: a Jinling Hospital; Department of Orthopaedics; State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University ; Nanjing , China.

ABSTRACT
Wear particle-induced osteolysis is the leading cause of aseptic loosening, which is the most common reason for THA (total hip arthroplasty) failure and revision surgery. Although existing studies suggest that osteoblast apoptosis induced by wear debris is involved in aseptic loosening, the underlying mechanism linking wear particles to osteoblast apoptosis remains almost totally unknown. In the present study, we investigated the effect of autophagy on osteoblast apoptosis induced by CoCrMo metal particles (CoPs) in vitro and in a calvarial resorption animal model. Our study demonstrated that CoPs stimulated autophagy in osteoblasts and PIO (particle-induced osteolysis) animal models. Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts. Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models. Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model. Collectively, these results suggest that autophagy plays a key role in CoPs-induced osteolysis and that targeting autophagy-related pathways may represent a potential therapeutic approach for treating particle-induced peri-implant osteolysis.

No MeSH data available.


Related in: MedlinePlus

The autophagy inhibitor 3-MA rescued osteoblast numbers and functional disturbance induced by CoPs. (A) Representative HE staining images of calvaria from each group. Osteoblasts are indicated by black arrowheads. Scale bar: 100 µm. EO, endosteum; PO, periosteum. (B) Osteoblast numbers/bone perimeter (mm−1) of endosteum and periosteum in (A). (C) Representative images of new bone formation of calvaria sections from each group were determined by calcein double labeling. Scale bar: 100 µm. (D) P-MAR and E-MAR in (C). (E) Real-time PCR of Alp, Ibsp, Col1a2 and Bglap3 of calvarial bone extracts from each group. Values are expressed as means ± S.E.M. n = 7 mice per group. *P < 0.05, **P < 0.01 vs. sham; #P < 0.05 vs. CoPs group.
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f0005: The autophagy inhibitor 3-MA rescued osteoblast numbers and functional disturbance induced by CoPs. (A) Representative HE staining images of calvaria from each group. Osteoblasts are indicated by black arrowheads. Scale bar: 100 µm. EO, endosteum; PO, periosteum. (B) Osteoblast numbers/bone perimeter (mm−1) of endosteum and periosteum in (A). (C) Representative images of new bone formation of calvaria sections from each group were determined by calcein double labeling. Scale bar: 100 µm. (D) P-MAR and E-MAR in (C). (E) Real-time PCR of Alp, Ibsp, Col1a2 and Bglap3 of calvarial bone extracts from each group. Values are expressed as means ± S.E.M. n = 7 mice per group. *P < 0.05, **P < 0.01 vs. sham; #P < 0.05 vs. CoPs group.

Mentions: To examine the role of autophagy in vivo, we used a murine calvaria resorption model, which is a commonly used model for studying aseptic loosening. HE (hematoxylin-eosin) staining analysis revealed that treatment with 3-MA, an autophagy inhibitor, markedly ameliorated the reduction in osteoblasts induced by CoPs (Fig. 5A and B). Calcein labeling, which permits dynamic bone histomorphometric analysis in vivo, was performed in sections of calvaria to evaluated new bone formation. CoPs treatment induced a decrease in the P-MAR (periosteum mineral apposition rates) relative to the sham group, but the decrease was significant ameliorated in mice cotreated with 3-MA (Fig. 5C and D). We further examined the expression of osteoblast markers in calvaria samples by real-time PCR analysis. The decreased expression of Alp (alkaline phosphatase) and Col1a2/collagen 1α2 caused by CoPs was largely rescued by 3-MA (Fig. 5E). Similar trends were observed in Ibsp (bone sialoprotein) and Bglap3 (bone gamma-carboxyglutamate protein 3), although the increased level in 3-MA-cotreated mice was not statistically significant (Fig. 5E).Figure 5.


Autophagy mediated CoCrMo particle-induced peri-implant osteolysis by promoting osteoblast apoptosis.

Wang Z, Liu N, Liu K, Zhou G, Gan J, Wang Z, Shi T, He W, Wang L, Guo T, Bao N, Wang R, Huang Z, Chen J, Dong L, Zhao J, Zhang J - Autophagy (2015)

The autophagy inhibitor 3-MA rescued osteoblast numbers and functional disturbance induced by CoPs. (A) Representative HE staining images of calvaria from each group. Osteoblasts are indicated by black arrowheads. Scale bar: 100 µm. EO, endosteum; PO, periosteum. (B) Osteoblast numbers/bone perimeter (mm−1) of endosteum and periosteum in (A). (C) Representative images of new bone formation of calvaria sections from each group were determined by calcein double labeling. Scale bar: 100 µm. (D) P-MAR and E-MAR in (C). (E) Real-time PCR of Alp, Ibsp, Col1a2 and Bglap3 of calvarial bone extracts from each group. Values are expressed as means ± S.E.M. n = 7 mice per group. *P < 0.05, **P < 0.01 vs. sham; #P < 0.05 vs. CoPs group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835204&req=5

f0005: The autophagy inhibitor 3-MA rescued osteoblast numbers and functional disturbance induced by CoPs. (A) Representative HE staining images of calvaria from each group. Osteoblasts are indicated by black arrowheads. Scale bar: 100 µm. EO, endosteum; PO, periosteum. (B) Osteoblast numbers/bone perimeter (mm−1) of endosteum and periosteum in (A). (C) Representative images of new bone formation of calvaria sections from each group were determined by calcein double labeling. Scale bar: 100 µm. (D) P-MAR and E-MAR in (C). (E) Real-time PCR of Alp, Ibsp, Col1a2 and Bglap3 of calvarial bone extracts from each group. Values are expressed as means ± S.E.M. n = 7 mice per group. *P < 0.05, **P < 0.01 vs. sham; #P < 0.05 vs. CoPs group.
Mentions: To examine the role of autophagy in vivo, we used a murine calvaria resorption model, which is a commonly used model for studying aseptic loosening. HE (hematoxylin-eosin) staining analysis revealed that treatment with 3-MA, an autophagy inhibitor, markedly ameliorated the reduction in osteoblasts induced by CoPs (Fig. 5A and B). Calcein labeling, which permits dynamic bone histomorphometric analysis in vivo, was performed in sections of calvaria to evaluated new bone formation. CoPs treatment induced a decrease in the P-MAR (periosteum mineral apposition rates) relative to the sham group, but the decrease was significant ameliorated in mice cotreated with 3-MA (Fig. 5C and D). We further examined the expression of osteoblast markers in calvaria samples by real-time PCR analysis. The decreased expression of Alp (alkaline phosphatase) and Col1a2/collagen 1α2 caused by CoPs was largely rescued by 3-MA (Fig. 5E). Similar trends were observed in Ibsp (bone sialoprotein) and Bglap3 (bone gamma-carboxyglutamate protein 3), although the increased level in 3-MA-cotreated mice was not statistically significant (Fig. 5E).Figure 5.

Bottom Line: Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts.Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models.Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model.

View Article: PubMed Central - PubMed

Affiliation: a Jinling Hospital; Department of Orthopaedics; State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University ; Nanjing , China.

ABSTRACT
Wear particle-induced osteolysis is the leading cause of aseptic loosening, which is the most common reason for THA (total hip arthroplasty) failure and revision surgery. Although existing studies suggest that osteoblast apoptosis induced by wear debris is involved in aseptic loosening, the underlying mechanism linking wear particles to osteoblast apoptosis remains almost totally unknown. In the present study, we investigated the effect of autophagy on osteoblast apoptosis induced by CoCrMo metal particles (CoPs) in vitro and in a calvarial resorption animal model. Our study demonstrated that CoPs stimulated autophagy in osteoblasts and PIO (particle-induced osteolysis) animal models. Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts. Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models. Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model. Collectively, these results suggest that autophagy plays a key role in CoPs-induced osteolysis and that targeting autophagy-related pathways may represent a potential therapeutic approach for treating particle-induced peri-implant osteolysis.

No MeSH data available.


Related in: MedlinePlus