The role of the specific, profilaggrin-containing keratohyalin granules in the developing epidermis of the fetal horse hoof

The adult equine hoof is subdivided into distinct segments with various keratinization modes. In the periople and bulbs of the heel, the epidermis forms a Stratum granulosum with basophilic keratohyalin granules during soft keratinization, whereas in the coronet, wall proper, sole, and frog, the epidermis undergoes hard keratinization by keratinizing and comifying without forming keratohyalin granules. The present study tests the hypothesis that the presence of specific (profilaggrin-containing) keratohyalin granules in the hoof epidermis is correlated with the water-binding capacity and mechanical properties of the hoof horn. To identify these specific profilaggrin-containing keratohyalin granules, tissue samples of fetal hooves were studied with histochemistry, immunohistochemistry, and transmission electron microscopy. In a fetal hoof, a Stratum granulosum is formed in all hoof segments in the wake of the establishment of a segment-specific papillary body, but at differing developmental stages, starting in the coronet, then in the wall proper, and later in the sole and frog, and disappearing again in the same sequence. In the terminal part of the wall proper (i.e., Zona alba), the Stratum granu/osum is retained at least until three days after birth. In the periople and bulbs of the heel, the Stratum granulosum appears last (and is retained in the adult) when the other segments have not yet completely lost theirs. The basophilic granules in the Stratum granulosum are specific profilaggrin-containing granules that were also described in the human skin. These observations are relevant for a better understanding of certain dyskeratotic processes in the hoof epidermis

Keratin and S100 calcium-binding proteins are major constituents of the bovine teat canal lining

The bovine teat canal provides the first-line of defence against pathogenic bacteria infecting the mammary gland, yet the protein composition and host-defence functionality of the teat canal lining (TCL) are not well characterised. In this study, TCL collected from six healthy lactating dairy cows was subjected to two-dimensional electrophoresis (2-DE) and mass spectrometry. The abundance and location of selected identified proteins were determined by western blotting and fluorescence immunohistochemistry. The variability of abundance among individual cows was also investigated. Two dominant clusters of proteins were detected in the TCL, comprising members of the keratin and S100 families of proteins. The S100 proteins were localised to the teat canal keratinocytes and were particularly predominant in the cornified outermost layer of the teat canal epithelium. Significant between-animal variation in the abundance of the S100 proteins in the TCL was demonstrated. Four of the six identified S100 proteins have been reported to have antimicrobial activity, suggesting that the TCL has additional functionality beyond being a physical barrier to invading microorganisms. These findings provide new insights into understanding host-defence of the teat canal and resistance of cows to mastitis

Strukturelle Faktoren mit Einfluss auf die Hornqualität und Prädilektionsstellen für Erkrankungen an der Fussungsfläche der Rinderklaue

The quality of the horn of the cattle hoof varies in the different segments of the ground surface adapted to weight bearing. Horn quality is influenced by the following main factors: the keratin proteins as the most important intracellular factor, the intercellular cementing substance as the intercellular factor, and the architecture of the cluster of horn cells, i.e. the arrangement of horn cells in tubular and intertubular horn. Differences in the structure and composition of these factors and their respective combination determine the different degrees of hardness of hoof horn, which are even palpable. In special places, as i.e. the white zone, the combination of all these above-mentioned factors determines sites of predilection for diseases of the cattle hoof like white line disease

A study of ultrasound-guided perineural injection of the caudal cervical spinal nerve roots in equine cadavers

OBJECTIVES: To develop an ultrasound-guided cervical perineural injection technique for horses and to evaluate and compare the distribution of contrast agent among perineural, intra-articular and periarticular injections. STUDY DESIGN: Prospective, experimental cadaveric study. ANIMALS: A total of 14 equine cadaveric necks. METHODS: Bilateral ultrasound-guided perineural injection technique for the caudal cervical spinal nerve roots (CSNRs 5-7) was developed. Paramagnetic or iodinated contrast was injected and the distribution of contrast was evaluated using magnetic resonance (MR) or computed tomography (CT) imaging, respectively. The presence of contrast in the CSNR region was determined by an observer unaware of the technique used for each injection performed. The ability of the perineural injection technique to distribute contrast agent to the CSNR region was compared with intra-articular and periarticular injection techniques. RESULTS: Perineural injection delivered contrast agent to the CSNR region 100% of the time and was significantly different when compared with intra-articular injection (p = 0.008). There was no difference in ability to deliver contrast agent to the CSNR region between the perineural and periarticular injection techniques or between the intra-articular and periarticular injection techniques. CONCLUSION AND CLINICAL RELEVANCE: The ultrasound-guided perineural injection technique developed in this study accurately delivered contrast agent to the CSNR region in equine cadavers. This technique could potentially be used for the diagnosis and treatment of cervical pain in horses, particularly in cases where intra-articular cervical articular process joint injections have not been beneficial. Further studies are necessary to assess the effectiveness of the ultrasound-guided perineural injection technique in live horses