Longitudinal Bone Growth, the Nutrition of the Epiphyseal Cartilages and the Local Blood Supply: An Experimental Study in the Rabbit

Enhanced proliferation of rabbit chondrocytes by using a well circulated nanoshock system

The gold nanorods (GNRs) embedded alginate-chitosan (scaffold), which was designed and fabricated to produce efficient handling of the cell proliferations. Scaffold embedded GNR (SGNR) and NIR (near infrared) irradiations are developing into an interesting medical prognosis tool for rabbit chondrocyte (RC) proliferation. SGNR contained a pattern of uniform pores. Biocompatibility and cellular proliferation achieved by disclosures to NIR irradiations, providing high cell survival. SGNR and NIR irradiations could produce mechanical and biochemical cues for regulating RCs proliferations. To determine the thermal stress, it exposed RCs to 39–42 °C for 0–240 min at the start point of the cell culture cycle. It produced photothermal stress in cellular surrounding (cells located adjacent to and within scaffold) and it deals with the proliferation behavior of RC. All the processes were modeled with experimental criteria and time evolution process. Our system could help the cell proliferation by generating heat for cells. Hence, the present strategy could be implemented for supporting cell therapeutics after transplantation. This implementation would open new design techniques for integrating the interfaces between NIR irradiated and non-irradiated tissues.

The Actions of IGF-1 in the Growth Plate and Its Role in Postnatal Bone Elongation

PURPOSE OF REVIEW

Bone elongation is a complex process driven by multiple intrinsic (hormones, growth factors) and extrinsic (nutrition, environment) variables. Bones grow in length by endochondral ossification in cartilaginous growth plates at ends of developing long bones. This review provides an updated overview of the important factors that influence this process.

RECENT FINDINGS

Insulin-like growth factor-1 (IGF-1) is the major hormone required for growth and a drug for treating pediatric skeletal disorders. Temperature is an underrecognized environmental variable that also impacts linear growth. This paper reviews the current state of knowledge regarding the interaction of IGF-1 and environmental factors on bone elongation. Understanding how internal and external variables regulate bone lengthening is essential for developing and improving treatments for an array of bone elongation disorders. Future studies may benefit from understanding how these unique relationships could offer realistic new approaches for increasing bone length in different growth-limiting conditions.

Transport properties of the human cartilage endplate in relation to its composition and calcification

STUDY DESIGN

The transport properties of solutes of different sizes and conformations were studied in cartilage endplates.

OBJECTIVES

The results were correlated with the composition of the cartilage matrix to determine if a relationship existed between this and the movement of molecules within it.

SUMMARY OF BACKGROUND DATA

Solute transport through the hyaline cartilage endplate is important not only for the physiologic and metabolic processes of that tissue, but also for those of the adjacent intervertebral disc. Movement of solutes depends on solute size, shape or charges, and the composition of the matrix itself. Changes in composition of the cartilage endplate, such as those that occur in degeneration or scoliosis, may affect transport.

METHODS

Partition and diffusion coefficients of solutes ranging in molecular weight from 115 to 70,000 d have been measured on cores of cartilage endplate. Transport properties were assessed in relation to core composition.

RESULTS

The shape and size of the solutes were found to affect their transport through cartilage matrix, with larger molecules being more highly excluded and diffusing more slowly. Long-chain polymers were able to penetrate the matrix less readily than the more globular molecules. The more hydrated the matrix, the higher the degree of penetration and the more easily solutes could move, in contrast to the inverse relationship between the other components of the matrix and solute transport. With increased proteoglycan, collagen, or calcification in the tissue, there was greater restriction of solute movement.

CONCLUSIONS

The proteoglycans normally found in the endplate regulate movement of solutes into and out of the disc. It has been shown previously that removal of proteoglycans from the endplate accelerates the loss of proteoglycans from the nucleus. Hence, a major function of the cartilage endplate may be to prevent fragments of osmotically active proteoglycans from leaving the disc.

Roentgen stereophotogrammetry for determination of bone growth. Comparison with the tetracycline method

Two different methods for determination of leg growth, the tetracycline method and roentgen stereophotogrammetry, were applied simultaneously in 41 young rabbits and compared 1 and 2, and 21 and 22 days after insertion of pins or balls of tantalum as markers. The tetracycline method gave slightly higher values than the other method, the difference varying between 77 and 6 micrometer/d on the first 2 days after marker insertion and between 32 and 1 micrometer/d after 3 weeks. When ball markers were used, agreement between the two methods was obtained 3 weeks after insertion. The difference between the methods used is due to that the two methods did not measure growth in precisely identical regions.