Protocol for isolation of adult mouse ear pinnae-derived primary fibroblasts

Researchers need in vitro models that mirror the biology of organisms. Primary fibroblasts play essential roles in wound healing and are present in many tissues. They are widely used in studies of cell cycle control, reprogramming, and aging. Though extraction protocols exist, alternatives that maximize use of available resources are useful. Here, we present our protocol for extracting primary fibroblasts from adult mouse ear pinnae, an often-discarded source of primary cells, which consistently yield large, pure numbers of primary fibroblasts.

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Primary fibroblasts are isolated from adult mouse ear pinnae, an often-unused tissue

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Fibroblasts can be isolated from mice of varying sex, age, and genotype

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Fibroblast cultures are highly pure, with >90% THY1.2 or PDGFRα staining

Aberration compensation for optical trapping of cells within living mice

Optical tweezers have been used to trap and manipulate microparticles within living animals. When the optical trap is constructed with an oil-immersion objective, it suffers from spherical aberration. There have been many investigations on the influence of spherical aberration when the particles are trapped in a water medium. However, the dependence of optical force on trapping depth is still ambiguous when the trapped particles are immersed in a high refractive index medium (such as biological tissue, refractive index solution) in experiments. In this paper, the microparticles are immersed in an aqueous solution of glycerol to mimic the cells within biological tissue. As the trapping laser is focused into the specimen, spherical aberration is introduced, degrading the optical trapping performance. It is similar to trapping in water; altering the effective tube length can also compensate for the spherical aberration of the optical trap in a high refractive index medium. Finally, the cells in living mice are trapped by the optical tweezers with the help of spherical aberration compensation.

Chondrogenesis of Human Adipose-Derived Stem Cells by In Vivo Co-graft with Auricular Chondrocytes from Microtia

OBJECTIVE

To evaluate the efficiency of chondrogenesis of human adipose-derived stem cells (ADSCs) induced by auricular chondrocytes from microtia via subcutaneous co-graft in nude mice.

METHODS

Human ADSCs and auricular chondrocytes were mixed at the ratio of 7:3 and suspended in 0.2 ml of Pluronic F-127 (5.0 × 10(7) cells/ml), and injected into Balb/c nude mice as the experimental group (Exp group). The same quantity of auricular chondrocytes (Ctr.1 group) or ADSCs (Ctr.2 group) in 0.2 ml of Pluronic F-127 was set as positive and negative control groups. The mixture of auricular chondrocytes (1.5 × 10(7) cells/ml) in 0.2 ml of Pluronic F-127 was set as the low concentration of chondrocyte control group (Ctr.3). At 8 weeks after grafting, the newly generated tissue pellets were isolated for morphological examination, haematoxylin and eosin staining, toluidine blue staining and safranin O staining of glycosaminoglycan (GAG), Masson's trichrome staining and immunohistochemical staining of type II collagen, and Verhoeff-iron-hematoxylin staining of elastic fibers. GAG content was determined by Alcian blue colorimetric method, and mRNA expression of type II collagen and aggrecan were examined by real-time PCR.

RESULTS

Cartilage-like tissue with a white translucent appearance and good elasticity was generated in the Exp and Ctr.1 groups. The tissue pellets in the Ctr.2 and Ctr.3 groups were much smaller than those in the Ctr.1 group. The mature cartilage lacunas could be observed in the Exp and Ctr.1 groups, while were rarely seen in the Ctr.3 group and not observed in the Ctr.2 group. The expression of cartilage-specific extracellular matrix such as type II collagen, GAG content, aggrecan, and elastic fibers in the Exp group was similar to that in the Ctr.1 group, whereas the expression of these extracellular matrix substances was significantly lower in the Ctr.2 and Ctr.3 groups (both P < 0.01).

CONCLUSION

Auricular chondrocytes from microtia can efficiently promote the chondrogenic differentiation and chondrogenesis of ADSCs by co-grafting in vivo.

NO LEVEL ASSIGNED

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[Comparison study of tissue engineered cartilage constructed with chondrocytes derived from porcine auricular and articular cartilage]

OBJECTIVE

To compare the tissue engineered cartilage constructed with chondrocytes derived from auricular and articular cartilage.

METHODS

Chondrocytes were isolated from porcine auricular and articular cartilage, and BMSCs were obtained from bone marrow aspirate and cultured. Each kind of chondrocytes were resuspended alone or mixed with BMSCs at a ratio of 1:1, and seeded onto PGA/PLA scaffolds to construct tissue engineered cartilage (n = 4). The constructs were cultured for 8 weeks in vitro and then subcutaneously implanted into nude mice for 6 weeks. The differences between chondrocytes monoculture from articular and auricular cartilage or between each of them co-cultured with BMSCs were evaluated by gross view, measurement of thickness and wet weight, histological examinations including H&E, Safranin O, type II collagen, and Ponceau's & Victoria blue staining, and gene expression analysis of cartilage related genes.

RESULTS

No obvious differences were found histologically among the complexes constructed in vitro 8 weeks except for few elastic fibers secreted in the auricular chondrocytes + BMSCs co-culture group. Neo-cartilage is thicker in the groups of articular chondrocytes (38. 1% than the group of auricular chondrocytes, P < 0.05) and articular chondrocytes + BMSCs co-culture (19.3% than the group of auricular chondrocytes + BMSCs, P < 0.05). However, after 6 weeks in vivo the elastic fibers were found positive in the complexes constructed by auricular chondrocytes, and its staining was even stronger and more homogenous in the group of auricular chondrocytes + BMSCs co-culture. The tissues generated by articular chondrocytes alone and co-cultured with BMSCs both formed the characteristic features of three-layer structure of hyaline cartilage and ossified in vivo with significant up-regulation of COL10A1 and MMP-13. To summarize, auricular chondrocytes formed the elastic cartilage while articular chondrocytes formed the hyaline cartilage during the development of tissue engineered cartilage either by monoculture or the co-culture with BMSCs.

CONCLUSIONS

The chondrogenic response of chondrocytes from different cartilage origins demonstrates that an initial chondrocyte and cartilage type recapitulates the same in later tissue-engineered development.

Supercontinuum light source enables in vivo optical microangiography of capillary vessels within tissue beds

This Letter reports on the use of a supercontinuum light source to achieve ultrahigh resolution and ultrahigh sensitive optical microangiography (OMAG) imaging of microcirculations within tissue beds in vivo. After passing through a specially designed optical filter with a passband of 120 nm centered on 800 nm, the light source is coupled into an optic-fiber-based OMAG system that provides a measured axial resolution of ∼3 μm over a ranging distance of 2 mm. Within this ranging distance, the system gives an averaged signal-to-noise ratio of 87 dB and a sensitivity roll-off of 7 dB at an A-scan rate of 70 kHz. We demonstrate the capability of the system to visualize a detailed microvascular perfusion map, including the single red blood cells within the capillaries, by imaging a mouse ear flap in vivo.

Transcutaneous immunization as preventative and therapeutic regimens to protect against experimental otitis media due to nontypeable Haemophilus influenzae

We have developed three nontypeable Haemophilus influenzae (NTHI) adhesin-derived immunogens that are significantly efficacious against experimental otitis media (OM) due to NTHI when delivered parenterally. We now expanded our preventative immunization strategies to include transcutaneous immunization (TCI) as a less invasive, but potentially equally efficacious, regimen to prevent OM due to NTHI. Additionally, we examined the potential of TCI as a therapeutic immunization regimen to resolve ongoing experimental OM. Preventative immunization with NTHI outer membrane protein (OMP) P5- and type IV pilus-targeted immunogens, delivered with the adjuvant LT(R192G-L211A), induced significantly earlier clearance of NTHI from the nasopharynges and middle ears of challenged chinchillas compared with receipt of immunogen or adjuvant alone. Moreover, therapeutic immunization resulted in significant resolution of established NTHI biofilms from the middle ear space of animals compared with controls. These data advocate TCI with the adhesin-directed immunogens as an efficacious regimen for prevention and resolution of experimental NTHI-induced OM.