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Protein kinase C delta mice exhibit structural alterations in articular surface, intra-articular and subchondral compartments.

Yang X, Teguh D, Wu JP, He B, Kirk TB, Qin S, Li S, Chen H, Xue W, Ng B, Chim SM, Tickner J, Xu J - Arthritis Res. Ther. (2015)

Bottom Line: Structural alterations in intra-articular and subchondral compartments are hallmarks of osteoarthritis, a degenerative disease that causes pain and disability in the aging population.The morphology and organization of chondrocytes were studied using confocal microscopy.Interestingly, loss of demarcation between articular cartilage and bone was concomitant with irregular chondrocyte morphology and arrangement.

View Article: PubMed Central - PubMed

Affiliation: Guangzhou Institute of Traumatic Surgery, the Fourth Affiliated Hospital of Medical College, Jinan University, Guangzhou, 510220, China. dr.yang1192@yahoo.com.

ABSTRACT

Introduction: Structural alterations in intra-articular and subchondral compartments are hallmarks of osteoarthritis, a degenerative disease that causes pain and disability in the aging population. Protein kinase C delta (PKC-δ) plays versatile functions in cell growth and differentiation, but its role in the articular cartilage and subchondral bone is not known.

Methods: Histological analysis including alcian blue, safranin O staining and fluorochrome labeling were used to reveal structural alterations at the articular cartilage surface and bone-cartilage interface in PKC-δ knockout (KO) mice. The morphology and organization of chondrocytes were studied using confocal microscopy. Glycosaminoglycan content was studied by micromass culture of chondrocytes of PKC-δ KO mice.

Results: We uncovered atypical structural demarcation between articular cartilage and subchondral bone of PKC-δ KO mice. Histology analyses revealed a thickening of the articular cartilage and calcified bone-cartilage interface, and decreased safranin O staining accompanied by an increase in the number of hypertrophic chondrocytes in the articular cartilage of PKC-δ KO mice. Interestingly, loss of demarcation between articular cartilage and bone was concomitant with irregular chondrocyte morphology and arrangement. Consistently, in vivo calcein labeling assay showed an increased intensity of calcein labeling in the interface of the growth plate and metaphysis in PKC-δ KO mice. Furthermore, in vitro culture of chondrocyte micromass showed a decreased alcian blue staining of chondrocyte micromass in the PKC-δ KO mice, indicative of a reduced level of glycosaminoglycan production.

Conclusions: Our data imply a role for PKC-δ in the osteochondral plasticity of the interface between articular cartilage and the osteochondral junction.

No MeSH data available.


Related in: MedlinePlus

Chondrocytes from protein kinase C delta (PKC-δ)−/− mice have defective proliferation and matrix production in vitro compared to chondrocytes from PKC-δ+/+ mice. a Low magnification scanned images of alcian blue-stained PKC-δ+/+ and PKC-δ−/− chondrocyte micromass cultures. b 100× magnified images showing the difference in the area of alcian blue staining in PKC-δ+/+ versus PKC-δ−/− chondrocyte micromass cultures (scale bar 100μm). c Analysis of alcian blue staining area in PKC-δ+/+ and PKC-δ−/− micromass cultures relative to PKC-δ+/+ (n = 5, ***p < 0.001). d Analysis of cell numbers in PKC-δ+/+ and PKCδ−/− micromass cultures relative to PKC-δ+/+ (n = 5, *p < 0.05). e Analysis of alcian blue staining area per cell in PKC-δ+/+ and PKC-δ−/− relative to in PKC-δ+/+ (n = 5, *p < 0.05)
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Fig5: Chondrocytes from protein kinase C delta (PKC-δ)−/− mice have defective proliferation and matrix production in vitro compared to chondrocytes from PKC-δ+/+ mice. a Low magnification scanned images of alcian blue-stained PKC-δ+/+ and PKC-δ−/− chondrocyte micromass cultures. b 100× magnified images showing the difference in the area of alcian blue staining in PKC-δ+/+ versus PKC-δ−/− chondrocyte micromass cultures (scale bar 100μm). c Analysis of alcian blue staining area in PKC-δ+/+ and PKC-δ−/− micromass cultures relative to PKC-δ+/+ (n = 5, ***p < 0.001). d Analysis of cell numbers in PKC-δ+/+ and PKCδ−/− micromass cultures relative to PKC-δ+/+ (n = 5, *p < 0.05). e Analysis of alcian blue staining area per cell in PKC-δ+/+ and PKC-δ−/− relative to in PKC-δ+/+ (n = 5, *p < 0.05)

Mentions: Finally, we examined synthesis ability of chondrocytes of PKC-δ KO mice using micromass culture and alcian blue staining. The results showed that PKC-δ KO cells have decreased alcian blue staining, indicating a reduced level of glycosaminoglycan production as compared to WT mice (Fig. 5), consistent with the ex vivo observations described above. We also analyzed cell proliferation rate of primary chondrocytes in micromass cultures. The results showed that there is a decreased proliferation rate in PKC-δ KO mature chondrocytes (Fig. 5d,e). These in vitro results are consistent with the ex vivo observations presented in Fig. 2, showing diminished chondrocyte cell density.Fig. 5


Protein kinase C delta mice exhibit structural alterations in articular surface, intra-articular and subchondral compartments.

Yang X, Teguh D, Wu JP, He B, Kirk TB, Qin S, Li S, Chen H, Xue W, Ng B, Chim SM, Tickner J, Xu J - Arthritis Res. Ther. (2015)

Chondrocytes from protein kinase C delta (PKC-δ)−/− mice have defective proliferation and matrix production in vitro compared to chondrocytes from PKC-δ+/+ mice. a Low magnification scanned images of alcian blue-stained PKC-δ+/+ and PKC-δ−/− chondrocyte micromass cultures. b 100× magnified images showing the difference in the area of alcian blue staining in PKC-δ+/+ versus PKC-δ−/− chondrocyte micromass cultures (scale bar 100μm). c Analysis of alcian blue staining area in PKC-δ+/+ and PKC-δ−/− micromass cultures relative to PKC-δ+/+ (n = 5, ***p < 0.001). d Analysis of cell numbers in PKC-δ+/+ and PKCδ−/− micromass cultures relative to PKC-δ+/+ (n = 5, *p < 0.05). e Analysis of alcian blue staining area per cell in PKC-δ+/+ and PKC-δ−/− relative to in PKC-δ+/+ (n = 5, *p < 0.05)
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Fig5: Chondrocytes from protein kinase C delta (PKC-δ)−/− mice have defective proliferation and matrix production in vitro compared to chondrocytes from PKC-δ+/+ mice. a Low magnification scanned images of alcian blue-stained PKC-δ+/+ and PKC-δ−/− chondrocyte micromass cultures. b 100× magnified images showing the difference in the area of alcian blue staining in PKC-δ+/+ versus PKC-δ−/− chondrocyte micromass cultures (scale bar 100μm). c Analysis of alcian blue staining area in PKC-δ+/+ and PKC-δ−/− micromass cultures relative to PKC-δ+/+ (n = 5, ***p < 0.001). d Analysis of cell numbers in PKC-δ+/+ and PKCδ−/− micromass cultures relative to PKC-δ+/+ (n = 5, *p < 0.05). e Analysis of alcian blue staining area per cell in PKC-δ+/+ and PKC-δ−/− relative to in PKC-δ+/+ (n = 5, *p < 0.05)
Mentions: Finally, we examined synthesis ability of chondrocytes of PKC-δ KO mice using micromass culture and alcian blue staining. The results showed that PKC-δ KO cells have decreased alcian blue staining, indicating a reduced level of glycosaminoglycan production as compared to WT mice (Fig. 5), consistent with the ex vivo observations described above. We also analyzed cell proliferation rate of primary chondrocytes in micromass cultures. The results showed that there is a decreased proliferation rate in PKC-δ KO mature chondrocytes (Fig. 5d,e). These in vitro results are consistent with the ex vivo observations presented in Fig. 2, showing diminished chondrocyte cell density.Fig. 5

Bottom Line: Structural alterations in intra-articular and subchondral compartments are hallmarks of osteoarthritis, a degenerative disease that causes pain and disability in the aging population.The morphology and organization of chondrocytes were studied using confocal microscopy.Interestingly, loss of demarcation between articular cartilage and bone was concomitant with irregular chondrocyte morphology and arrangement.

View Article: PubMed Central - PubMed

Affiliation: Guangzhou Institute of Traumatic Surgery, the Fourth Affiliated Hospital of Medical College, Jinan University, Guangzhou, 510220, China. dr.yang1192@yahoo.com.

ABSTRACT

Introduction: Structural alterations in intra-articular and subchondral compartments are hallmarks of osteoarthritis, a degenerative disease that causes pain and disability in the aging population. Protein kinase C delta (PKC-δ) plays versatile functions in cell growth and differentiation, but its role in the articular cartilage and subchondral bone is not known.

Methods: Histological analysis including alcian blue, safranin O staining and fluorochrome labeling were used to reveal structural alterations at the articular cartilage surface and bone-cartilage interface in PKC-δ knockout (KO) mice. The morphology and organization of chondrocytes were studied using confocal microscopy. Glycosaminoglycan content was studied by micromass culture of chondrocytes of PKC-δ KO mice.

Results: We uncovered atypical structural demarcation between articular cartilage and subchondral bone of PKC-δ KO mice. Histology analyses revealed a thickening of the articular cartilage and calcified bone-cartilage interface, and decreased safranin O staining accompanied by an increase in the number of hypertrophic chondrocytes in the articular cartilage of PKC-δ KO mice. Interestingly, loss of demarcation between articular cartilage and bone was concomitant with irregular chondrocyte morphology and arrangement. Consistently, in vivo calcein labeling assay showed an increased intensity of calcein labeling in the interface of the growth plate and metaphysis in PKC-δ KO mice. Furthermore, in vitro culture of chondrocyte micromass showed a decreased alcian blue staining of chondrocyte micromass in the PKC-δ KO mice, indicative of a reduced level of glycosaminoglycan production.

Conclusions: Our data imply a role for PKC-δ in the osteochondral plasticity of the interface between articular cartilage and the osteochondral junction.

No MeSH data available.


Related in: MedlinePlus