The local mediators nitric oxide (NO) and prostaglandin E, (PGE ) play a role in the cascade of extracellular matrix breakdown in articular cartilage.In the present study the spontaneous production of NO and PGE, in explant cultures of equine synovial membrane and articular cartilage and their concentration over tjme n culture was investigated and correlated.Synovial membrane and articular cartilage was harvested from metacarpophalangeal jonts of 33 horses durlng arthroscopic surgery (n=4) or after being slaughtered/euthanised for reasons other than infectious or metabolic dlsease (n=29).Trssues were cultured as explant cuJtures in the presence of 4 ml Ham's F 12 medium, supplemented with streptomycin (100 pg/ml) and penicillin (100 U/ml) and incubated in a 5% CO2 and water saturated atmosphere for 8 days.Re sults showed that generally equine synovial membrane produced less NO than articular cartilage explant cultures with comparable wet weights/ml of media, but significantly more PGE, (P<0.05).The concentrations of both mediators were relatively stable over the first 4 days of culture, at least in the group of 25 mg wet wdghvml of media.In this group, there was a weak tendency noticed for NO to decrease, and PGE, to increase over time with day 4 being the intersection for both.Tissue cultures of articular cartilage with 12.5 mg wet weight/ml of culture media produced less reliable results, especially with NO measurements, which was thought to be associated with the sensitivity of the assay.lt is recommended to collect conditioned media for the measurements of NO and PGE, within the first 4 days of explant culture, since atter this time period culture effects may mask the results at least for NO measurements.Both mediators may be factors that play an impor tant role in the local med ation of ioint inflammations.
Summary Cases of cystic bone lesions in horses and humans were reviewed in the literature. These lesions are radiolucent areas of bone, recognized as subchondral cystic lesions in the horse (SCL), intra-osseous ganglia (IOG), subchondral bone cysts secondary to osteoarthrosis (OAC), and unicameral bone cysts (UCB) in humans. Their morphology is quite similar, consisting of lesions with a distinct cyst wall, and a cavity filled with fibrous tissue and yellowish mucoid fluid. The lesions are surrounded by sclerotic bone and can be easily diagnosed radiographically. SCL, IOG and OAC occur in the subchondral bone close to the adjacent joint, whereas UCB occur in the metaphysis of long bones. Their aetiology and pathogenesis is still unknown, although primary damage to the subchondral bone, cartilage or local blood supply and growth disturbances are discussed. In this review 703 lesions of SCL in horses, 289 lesions of IOG and 1460 lesions of UCB in humans were compared in their anatomical location and clinical signs. SCL and OAC resembled each other with respect to anatomical location. A correlation of affected bones could not be found for all four groups. Clinical presentation concerning age was most similar for SCL and UCB with both lesions mainly occurring in young individuals. Gender predominance of males was present in SCL, IOG and UCB. Clinical diagnosis was either incidental, or connected with intermittent pain in all lesions except for OAC. Additionally, the lesions were also found in conjunction with degenerative joint disease (SCL, OAC) or pathological fractures (UCB). Cystic bone lesions were either treated conservatively, surgically with curettage alone, curettage in combination with grafting procedures, or intra-lesional application of corticosteroids. SCL and UCB were similar in their biological behaviour concerning their slow response to the therapy and relatively high recurrence rate. None of the cystic bone lesions were comparable, and a common aetiology and pathogenesis could not be found. In a literature review cases of cystic bone lesions in horses and humans were compared with the goal to find a common aetiology and pathogenesis. Cystic bone lesions occur in horses as subchondral cystic lesions (SCL), and in humans as either intra-osseous ganglia (IOG), subchondral cystic lesions secondary to osteoarthrosis (OAC) or unicameral bone cysts (UCB). IOG and OAC compare with SCL mainly in the anatomical location. IOG and SCL resemble each other in size, clinical signs and histology, whereas UCB and SCL show a similar biological behaviour regarding their therapeutic response and recurrence rate. None of the cystic bone lesions in humans were comparable to the SCL in horses in all aspects. A common aetiology and pathogenesis could not be established.
Abstract Background Gray horses are predisposed to equine malignant melanoma (EMM) with advancing age. Depending on the tumor’s location and size, they can cause severe problems (e.g., defaecation, urination, feeding). A feasible therapy for EMM has not yet been established and surgical excision can be difficult depending on the location of the melanoma. Thus, an effective and safe therapy is needed. Naturally occurring betulinic acid (BA), a pentacyclic triterpene and its synthetic derivate, NVX-207 (3-acetyl-betulinic acid-2-amino-3-hydroxy-2-hydroxymethyl-propanoate) are known for their cytotoxic properties against melanomas and other tumors and have already shown good safety and tolerability in vivo. In this study, BA and NVX-207 were tested for their permeation potential into equine skin in vitro in Franz-type diffusion cell (FDC) experiments after incubation of 5 min, 30 min and 24 h, aiming to use these formulations for prospective in vivo studies as a treatment for early melanoma stages. Potent permeation was defined as reaching or exceeding the half maximal inhibitory concentrations (IC 50 ) of BA or NVX-207 for equine melanoma cells in equine skin samples. The active ingredients were either dissolved in a microemulsion (ME) or in a microemulsion gel (MEG). All of the formulations were transdermally applied but the oil-in-water microemulsion was administered with a novel oxygen flow-assisted (OFA) applicator (DERMADROP TDA). Results All tested formulations exceeded the IC 50 values for equine melanoma cells for BA and NVX-207 in equine skin samples, independently of the incubation time NVX-207 applied with the OFA applicator showed a significant time-dependent accumulation and depot-effect in the skin after 30 min and 24 h ( P < 0.05). Conclusions All tested substances showed promising results. Additionally, OFA administration showed a significant accumulation of NVX-207 after 30 min and 24 h of incubation. Further in vivo trials with OFA application are recommended.
