Because minipig skin is similar to human skin in anatomy and physiology, establishing an atopic dermatitis (AD) minipig model seems meaningful. We applied 1-fluoro-2,4-dinitrobenzene (DNFB) or ovalbumin onto the back skin of five Yucatan minipigs aged 8–10 months and 19 kg in median weight. Two minipigs with the same parameters served as controls. Both DNFB and ovalbumin mediated epithelial hyperplasia, spongiosis, and immune cell infiltration in the dermis, which is a typical histopathological feature of AD. Moreover, AD upregulated the Th1- and Th2-related cytokine expressions in DNFB- or in ovalbumin-treated skin. Notably, AD-induced minipigs exhibited greater cytokine serum concentrations. Histopathological finding and cytokine analysis revealed that DNFB or ovalbumin mediates AD. However, ovalbumin-treated minipig is a more reliable and precise AD model owing to the DNFB-induced severe skin damage. In summary, ovalbumin-treated skin shows similar AD as human in histopathological and molecular analysis.

Objective—To characterize the response of skin of nonallergic horses following ID injection of polyclonal rabbit anti-canine IgE (anti-IgE) and rabbit IgG. Animals—6 healthy horses. Procedures—Skin in the cervical area was injected ID with anti-IgE and IgG. Wheal measurements and skin biopsy specimens were obtained before and 20 minutes and 6, 24, and 48 hours after injection. Tissue sections were evaluated for inflammatory cells at 4 dermal depths. Immunohistochemical analysis for CD3, CD4, and CD8 was performed, and cell counts were evaluated. Results—Anti-IgE wheals were significantly larger than IgG wheals at 20 minutes and 6 and 24 hours after injection. There were significantly more degranulated mast cells after anti-IgE injection than after IgG injection. There were significantly more eosinophils at 6, 24, and 48 hours and neutrophils at 6 hours after anti-IgE injection, compared with cell numbers at those same times after IgG injection. There were significantly more eosinophils in the deeper dermis of anti-IgE samples, compared with results for IgG samples. No significant differences between treatments were detected for CD3+, CD4+, or CD8+ cells. Conclusions and Clinical Relevance—Injection of anti-IgE antibodies was associated with the development of gross and microscopic inflammation characterized by mast cell degranulation and accumulation of inflammatory cells, particularly eosinophils and neutrophils. This pattern appeared to be similar to that of horses with naturally developing allergic skin disease, although lymphocytes were not increased; thus, ID injection of anti-IgE in horses may be of use for evaluating allergic skin diseases of horses.

Objective: To determine the distribution of cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2) in skin (including hair follicles and sweat and sebaceous glands) of clinically normal dogs and dogs with atopic dermatitis (AD) and to compare results with those for positive control samples for CB1 (hippocampus) and CB2 (lymph nodes). Sample: Skin samples from 5 healthy dogs and 5 dogs with AD and popliteal lymph node and hippocampus samples from 5 cadavers of dogs. Procedures: CB1 and CB2 were immunohistochemically localized in formalin-fixed, paraffin-embedded sections of tissue samples. Results: In skin samples of healthy dogs, CB1 and CB2 immunoreactivity was detected in various types of cells in the epidermis and in cells in the dermis, including perivascular cells with mast cell morphology, fibroblasts, and endothelial cells. In skin samples of dogs with AD, CB1 and CB2 immunoreactivity was stronger than it was in skin samples of healthy dogs. In positive control tissue samples, CB1 immunoreactivity was detected in all areas of the hippocampus, and CB2 immunoreactivity was detected in B-cell zones of lymphoid follicles. Conclusions and Clinical Relevance: The endocannabinoid system and cannabimimetic compounds protect against effects of allergic inflammatory disorders in various species of mammals. Results of the present study contributed to knowledge of the endocannabinoid system and indicated this system may be a target for treatment of immune-mediated and inflammatory disorders such as allergic skin diseases in dogs.

OBJECTIVE To determine whether a stainless steel implant sterilized with a novel cold atmospheric plasma sterilization (CAPS) device adversely affects local tissues in rabbits and whether CAPS was as effective as steam sterilization with an autoclave to inactivate Pasteurella multocida. ANIMALS 31 healthy New Zealand White rabbits. PROCEDURES Steam-autoclaved stainless steel implants inoculated with P multocida underwent a second steam autoclave sterilization (AIA) or CAPS (AICAPS). One AIA implant and 3 AICAPS implants were randomly placed subcutaneously at 4 sites in 21 rabbits (84 implants). These rabbits were monitored daily for 5 days for evidence of systemic illness and local tissue reactions at the implantation sites and then euthanized. Samples were taken from each implant site for bacterial culture and histologic examination. RESULTS Cultures of samples obtained from all sites were negative for bacterial growth. No significant difference was observed in mean skin thickness or erythema between AIA and AICAPS implant sites on any observed day. Also, individual histologic grades for the epidermis, dermis, subcutis, and muscle and total histologic grade were not significantly different between AIA and AICAPS implant sites. CONCLUSIONS AND CLINICAL RELEVANCE Cold atmospheric plasma sterilization was noninferior to steam sterilization of P multocida–contaminated stainless steel implants in the rabbits in the present study. However, studies of the efficacy of CAPS for inactivation of other important bacteria are needed.

Photobiomodulation is an accepted regenerative medicine treatment modality used to stimulate tissue repair, mediate inflammation, and improve mobility in humans and animals. The objective of this study was to assess the influence of laser power and wavelength, coat length and color, and shaving on in-vivo photon delivery by therapeutic laser in dogs. Forty-seven dogs of various breeds and coat colors (17 black, 15 brown, and 15 white) and with varying coat lengths were assessed with 2 commercially available veterinary lasers. Photons were delivered to the lateral aspect of the inguinal fold and calcaneal tendon, with direct penetration through the dermis, as well as dermis and tendon, as measured with a thermopile laser sensor. Significant impacts on laser transmission were noted for laser power (P = 0.001), wavelength (P < 0.002), coat color (P < 0.001), and shaved coat (P < 0.001). Percent transmission was higher for a class IV 810/980 nm wavelength laser at 0.5 W than for a class IIIb 904 nm laser (P < 0.001). There was a significant difference between transmission of photons among white, brown, and black coats, with less transmission noted with increasing coat pigment (P < 0.001). Transmission was greater at higher power levels (3 W, 5 W) Results showed significant differences in laser transmission for all variables assessed, with the exception of coat length, which was not a significant predictor of laser transmission. As transmission was significantly reduced in darker and unshaved areas, higher power lasers may be necessary for darker pigmented dogs and shaving of hair is recommended before laser therapy.

OBJECTIVE To examine the equine foot for the presence of sensory receptors including Merkel cells and small lamellated Pacinian-like corpuscles (SLPCs). SAMPLE Forefeet obtained from 7 horses following euthanasia for reasons other than foot disease. PROCEDURES Disarticulated feet were cut into either sagittal sections or cross sections and immersed in neutral-buffered 4% formalin. Following fixation, samples were obtained from the midline of the dorsal aspect of the hoof wall and from the frog (cuneus ungulae) between the apex and central sulcus. The formalin-fixed, paraffin-embedded hoof wall and frog sections were routinely processed for peroxidase immunohistochemistry and stained with H&E, Alcian blue, and Masson trichrome stains for histologic evaluation. RESULTS Sensory myelinated nerves and specific receptors were identified within the epidermal and dermal tissues of the equine foot including the hoof wall laminae, coronet, and frog. Merkel cells were identified with specific antisera to villin, cytokeratin 20, and protein gene product 9.5 in coronet epidermis and hoof wall. These cells were interspersed among basilar keratinocytes within the frog, coronary epidermis, and secondary epidermal laminae. The SLPCs were present within the superficial dermis associated with the central ridge of the frog (ie, frog stay). Numerous S100 protein and protein gene product 9.5 immunoreactive sensory nerves in close proximity to these receptors were present throughout the dermal tissues within both the frog and hoof wall. CONCLUSIONS AND CLINICAL RELEVANCE The presence of Merkel cells and SLPCs that are known to detect tactile and vibrational stimuli, respectively, further defined the diverse range of neural elements within the equine foot.