Histological evaluation of wound healing in horses treated with the protein-free hemodialysate Solcoseryl and its hexosylceramide fraction

Topical treatments in equine wound management

Wound repair is a complex series of coordinated events regulated by a delicately orchestrated cascade of cytokines and growth factors that restore the structural integrity of damaged tissue. Manipulation of the growth factor profile or wound environment through topical application of therapeutic agents could positively influence the rate and quality of wound repair. Transforming growth factor-beta,platelet-rich plasma, activated macrophage supernatant, and growth hormone are sources of mediators that may facilitate wound healing. Solcoseryl, ketanserin, tripeptide- and tetrapeptide-copper complexes, maltodextrin, live yeast cell derivative, corticosteroids,aloe vera, acemannan, phenytoin, honey, sugar, and maggots may modify the wound environment and promote repair. The process of wound healing is complex, however, and it is currently unknown whether any one agent can ameliorate all issues of repair or cover all vulnerabilities of impaired wound healing.

The effectiveness of the haemodialysate Solcoseryl for second-intention wound healing in horses and ponies

Second-intention healing of limb wounds in horses is often problematic. Solcoseryl is a protein-free, standardized dialysate/ultrafiltrate (HD) derived from calf blood, which has been shown to improve healing in both animals and humans. The efficacy of HD in the healing of deep wounds in horses and ponies was investigated. Deep wounds of 20 by 35 mm were created on both metatarsi (skin, subcutis, periosteum) and on both femoral biceps muscles (skin, subcutis, muscle) of five horses and five ponies. The wounds on one side were treated with HD, four times a week during the period that the wounds were bandaged and once daily thereafter. The wounds on the other side were left untreated. In the first 4 weeks of the healing period HD stimulated healing but inhibited healing thereafter. This pattern was significant for all wound groups (P < 0.001). Because of this change in effect, the overall effect on wound healing over the entire period was not significant (P = 0.77). HD stimulated healing initially by provoking a greater initial inflammatory response, faster contraction and faster formation of granulation tissue. Subsequently, HD inhibited healing because it significantly delayed epithelialization and caused protracted inflammation. The effects of HD were most pronounced in the horses. Because this study distinguished between contraction and epithelialization, it could be shown that HD stimulated contraction but inhibited epithelialization. Therefore, HD is useful in horses for the treatment of deep wounds during the initial phase of healing by second intention, i.e. during the first weeks when wound contraction can be expected. Treatment should be ceased when epithelialization becomes predominant.

Differences in second-intention wound healing between horses and ponies: histological aspects

The histological aspects of second-intention healing were studied in 5 horses and 5 ponies. Biopsies were taken weekly from standardised wounds on the metatarsus and femoral biceps muscle of one horse and one pony. Sections were stained to enable cell counting and the detection of DNA synthesis, fibrin, smooth muscle actin (SMA), collagen, and bacteria. In the ponies, the number of polymorphonuclear leucocytes (PMNs) was high during the first 3 weeks and subsequently decreased rapidly. In the horses, the initial number of PMNs was lower, but remained persistently elevated during the evaluation period. PMNs were found mainly in the superficial zones. Significantly more fibrin was present in the wounds of the horses. No significant differences were observed in the number of fibroblasts, the amounts of SMA and collagen. However, myofibroblasts were significantly less regularly organised in the wounds of the horses, particularly in the metatarsal wounds. The mitotic activity of the epithelium was temporally reduced in week 3. The mitotic activity of the granulation tissue was initially high but declined rapidly from week 1 onwards, with the exception of the metatarsal wounds of the horses, in which mitotic activity remained significantly higher. Histology confirmed and explained the macroscopical differences in wound healing between horses and ponies by the strict organisation of the myofibroblasts and the more effective acute inflammation in the ponies. Stimulation of the organisation of myofibroblasts and improvement of the efficacy of the inflammatory response in horses may therefore result in better second-intention wound healing in horses in clinical practice.

Evaluation of wound healing of the teat with and without low level laser therapy in dairy cattle by laser Doppler flowmetry in comparison with histopathology, tensiometry and hydroxyproline analysis

Perforated teat wounds in eight lactating Holstein-Friesian cows were closed by four suture patterns with or without low level laser therapy (LLLT). Wound healing was evaluated by laser Doppler flowmetry (LDF), tensiometry and hydroxyproline analysis, and compared with histopathological examination. The three-layer pattern provided the best healing of the entire teat. Mucosal hyperplasia was observed in Gambee and continuous two-layer pattern while eversion of the skin, presence of suture tracts and a greater amount of granulation tissue were observed with the continuous and interrupted two-layer patterns. The epidermis in LLLT groups more closely resembled the normal epidermis, and collagen fibres were denser, thicker and better arranged in LLLT than in non-LLLT groups. LDF, tensiometry and hydroxyproline analysis correlated well with histopathological examination. The results suggest that LDF, a more rapid, less invasive and painless procedure, can replace tensile strength measurement or hydroxyproline analysis to assess the progress of teat wound healing.

Fibroblast migration and proliferation during in vitro wound healing. A quantitative comparison between various growth factors and a low molecular weight blood dialysate used in the clinic to normalize impaired wound healing

During the formation of granulation tissue in a dermal wound, platelets, monocytes and other cellular blood constituents release various peptide growth factors to stimulate fibroblasts to migrate into the wound site and proliferate, in order to reconstitute the various connective tissue components. The effect on fibroblast migration and proliferation of these growth factors, and of Solcoseryl (HD), a deproteinized fraction of calf blood used to normalize wound granulation and scar tissue formation, was quantified in vitro. The presence of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta) and hemodialysate (HD) increased the number of cells in the denuded area, i.e., in the "wound space" of an artificially ruptured monolayer of LM-fibroblasts (mouse lung fibroblasts). When cell proliferation was blocked with Mitomycin C, in the first 24 h all factors, i.e., bFGF, PDGF, TGF-beta and HD, promoted cell migration, whereas after 48 h it became obvious that each factor stimulated both migration and proliferation, each in a characteristic way. The effects were significant and more distinct after 48 h, following the order: PDGF (46%) approximately bFGF (87%) > HD (45%) approximately TGF-beta (40%) > control (62%). The relative contributions of migration after inhibiting proliferation are given in brackets. The modulatory activity of HD was localized in its hydrophilic fraction. It was destroyed by acid hydrolysis. Furthermore, this activity could be blocked by protamine sulfate, an inhibitor blocking peptide growth factor receptor binding.

Morphometric assessment of wound healing in rats treated with a protein-free haemodialysate

Morphological changes during soft-tissue repair are prime indicators of the processes involved in wound healing. A method has been developed to quantify such changes and applied for assessing the healing of partial thickness dermatome wounds treated either with Solcoseryl jelly or the matching vehicle. After 4 days of treatment, the active-treated wounds had already reached the reparative phase, whereas the vehicle-treated wounds were still in the proliferative phase. Furthermore, wound re-epithelialization was significantly improved under active treatment (P less than 0.005).

Topical treatment of standardized burns with a protein-free haemodialysate

The utility of the protein-free haemodialysate Solcoseryl (HD) in the treatment of chronic skin ulcers and minor burns is well documented (Haigis et al., 1985). In this study the effects of HD ointment and HD gel on the healing of standardized deep partial thickness burns were investigated in rats. Treatment with HD-containing topical agents significantly reduced healing time (P less than or equal to 0.01) in comparison with non-treated controls; HD ointment and HD gel reduced relative healing rates by 20 per cent and 15 per cent respectively. Macroscopic and histological findings indicate that the effects of HD start in the early phase of the healing process (inflammatory/exudative), and that the entire healing process is improved.