The Effect of Glucosamine and Chondroitin on Stressed Equine Cartilage Explants

Effective prevention and treatment of osteoarthritis for horses is still needed. This research tests the ability of glucosamine and chondroitin sulfate (GLN/CS) to mitigate inflammatory and mechanical stress in vitro. In this study, GLN/CS mediate this effect by a decrease of the synthesis of nitric oxide (NO) and a decrease of proteoglycan release from the extracellular matrix in stressed cartilage explants. Explants were cultured with interleukin-1 (IL-1) + mechanical trauma with and without GLN/CS. NO and prostaglandin E2 were measured as indicators of an inflammatory response. Glycosaminoglycans were measured as an indicator of cartilage breakdown. NO levels in the stressed explants with GLN/CS treatment were lower than the IL-1 + mechanical impact treatment alone and did not differ from control group. The glycosaminoglycan release was also lower in the GLN/CS treatment than the IL-1 + mechanical impact treatment, although the prostaglandin E2 concentration was not affected. This study offers some evidence that GLN/CS treatment can partially mitigate the catabolic response to inflammatory stress and mechanical trauma in equine cartilage explants. These results provide additional support for the continued study on the benefit of GLN/CS for horses with cartilage degeneration.     

Systemic Proteoglycan Deposition Is Not a Characteristic of Equine Degenerative Suspensory Ligament Desmitis (DSLD)

Recently Degenerative Suspensory Ligament Desmitis (DSLD) has been proposed to be a disease characterized by systemic deposition of proteoglycan (PG) in connective tissues. To investigate this hypothesis, 6 clinically affected Peruvian Paso horses were compared to 2 unaffected quarterhorses and one unaffected standardbred. Histological sections of limb ligaments and tendons, nuchal ligaments, aortas, hearts, eyes, visceral organs and brains from both groups were stained with H&E as well as special stains for PG. Safranin-O stained sections were found to be optimal for elucidating the presence of PG. Although lesions characteristic of DSLD were present in suspensory ligaments of each clinically affected horse, including foci of chondroid metaplasia with abundant PG, a similar but less pronounced pattern of PG deposition was present in control horses. In contrast to findings of the previous study, PG deposition was not unique to DSLD horses, and PG deposition in aortas and nuchal ligaments of some control horses exceeded levels of PG present in similar tissue of DSLD horses. Furthermore, the “vascular lesion” described in the media of arteries as cellular separation and intercellular amorphous matrix deposition was within the spectrum of changes recognized in both affected and unaffected horses. We found no evidence that DSLD is a systemic PG deposition disease.     

马疱疹病毒1型感染马疾病模型的建立及评价

试验旨在建立马疱疹病毒1型（Equine herpesvirus type1,EHV-1）人工发病模型,确定EHV-1感染马的半数感染量（ID₅₀）及感染发病的判定标准,为该病的预防与治疗药物的研发奠定基础。以新疆伊犁地区某发病马场流产胎儿中分离的EHV-1 XJ2015株为研究对象,设立4组不同病毒剂量感染组及对照组,经鼻内喷雾感染马,5 mL/匹,每天观察试验马的临床症状和发病情况,14 d后进行剖检,观察各组织脏器病理变化并应用实时荧光定量PCR方法检测鼻腔排毒及病毒分布情况。结果显示,EHV-1 XJ2015株感染马的ID₅₀为10^-6.67/5 mL,其病毒含量为10^4.33 TCID₅₀/mL。与对照组相比,1×10⁶和1×10⁵ TCID₅₀/mL感染组马临床评分显著升高,主要表现为体温升高（高达39.5 ℃,一般持续2~6 d）、食欲不振、流浆液性鼻液和下颌淋巴结肿大;且1×10⁶和1×10⁵ TCID₅₀/mL感染组试验马均表现出不同程度的排毒,肺脏及脑组织中可检测出大量病毒,与对照组相比极显著或显著升高（P<0.01;P<0.05）;病理学检查发现,患马脑组织出现非化脓性脑炎及神经元水肿,肺脏组织出现间质性肺炎、嗜中性粒细胞、炎性细胞浸润、出血和肺泡间隔增厚。以上结果表明,EHV-1 XJ2015株对马具有较强的致病性,患病马临床症状典型,病毒主要随鼻液排出,并富集在肺脏及脑组织,通过上述指标确定EHV-1感染马发病的判定标准,本试验成功建立EHV-1感染本体动物疾病模型。     

Evaluation of Capsule Permeability in the Equine Blastocyst

Recipient pregnancy rates following transfer of frozen-thawed blastocyst stage equine embryos remain low. To date, no protocol has been developed that would allow successful cryopreservation of this stage of embryos. These experiments characterized the amount of glycerol entering equine embryos after incubation in 1.4 M and 3.4 M glycerol solutions using tritiated glycerol and a liquid scintillation counter. Blastocyst stage equine embryos (n = 27) were collected and incubated for 15 minutes in either 1.4 M (n = 14) or 3.4 M (n = 13) tritiated glycerol solutions. Disintegrations per minute were then determined, and the percent glycerol uptake was calculated for each embryo. Percent glycerol uptake for 1.4 M or 3.4 M glycerol treatment groups was not different (P = .68). However, it was higher (P = .05) in embryos with a diameter of ≤600 μm (3.6%) compared with embryos with a diameter of >600 μm (0.4%). We concluded that glycerol more readily permeates into embryos with a diameter of ≤600 μm that do not possess a fully functional capsule compared with embryos with a diameter of >600 μm with a fully formed capsule.     

The Effect of Exercise on the Healing of Articular Cartilage Defects in the Equine Carpus

Arthroscopic surgery was performed on 12 horses (2-4 years of age) to create a 7 x 14 mm full-thickness cartilage defect in one radial carpal bone and in the contralateral third carpal bone. Six horses remained confined to a small paddock and six horses underwent a program of increasing exercise consisting of walking, trotting, and cantering for 13 weeks. All lesions showed evidence of healing at week 6 that progressed to more complete healing at week 13. There was no difference in the amount of repair tissue covering the defect. Histologically, the lesions healed with a combination of fibrous tissue and fibrocartilage. The repair tissue was significantly thicker in the exercised horses but there was no difference in repair quality. It was concluded that radial carpal and third carpal lesions have an equal ability to heal and that early postoperative exercise is not detrimental to the repair tissue within these carpal cartilage defects.     

Treatment of Bilateral Medial Femoral Condyle Articular Cartilage Fissures in a Horse Using Bone Marrow-Derived Multipotent Mesenchymal Stromal Cells

The objective of this study was to describe the use, and outcome, of multipotent mesenchymal stromal cells (MSCs) in the treatment of equine articular cartilage defects of the medial femoral condyle. A 4-year-old Thoroughbred gelding (n = 1) with bilateral stifle athroscopy was found to have bilateral articular cartilage fissure defects of the medial femoral condyles with concurrent cranial cruciate ligament injury. Bone marrow derived MSCs were isolated, expanded, and suspended in a partially autologous fibrin glue. The initial cell/fibrin glue mixture was delivered arthroscopically into the articular cartilage defects 90 days after the initial arthroscopic examination. Follow-up treatments included two additional injections of MSCs suspended in lactated Ringers solution, 5 and 13 months after the initial examination, directly into the joint. Post-treatment outcome was assessed by arthroscopic examination and by comparison of preinjury and post-treatment performance records. Arthroscopic evaluation 4 months after the initial MSC treatment revealed marked smoothing, reduction in the depth of cartilage defects and observation of moderate improvement in the cranial cruciate ligament. Approximately 15 months after the initial MSC treatment the horse returned to racing. Analysis of race records demonstrated that the post-treatment (including all three MSC treatments) average race earnings (earnings per start) were comparable with those predating the initial injury. The favorable clinical response in the face of an unknown, but likely, guarded prognosis suggest that MSC therapy is not deleterious and may augment healing of articular cartilage fissures of the medial femoral condyle. MSCs represent a viable and promising alternative therapy in the treatment of articular cartilage injuries in performance horses.     

Evaluation of Equine Albumin Solution in Fluid Therapy in Horses with Colic

Equine albumin solution can be a good therapeutic option in fluid replacement for treatment of horses with colic. The purpose of this study was to evaluate the effects of initial fluid therapy with equine albumin solution in horses presenting with colic and mild-to-moderate dehydration, and to compare this therapy with fluid therapy based on crystalloids alone. Nineteen horses of both genders presenting with colic and mild-to-moderate dehydration were used. Animals were randomly assigned to one of two groups (control: fluid therapy based on crystalloid solutions; experimental: fluid therapy based on equine albumin and crystalloid solutions). Physical examination, hematocrit determination, blood gas analysis, serum biochemistry, blood and peritoneal lactate assessment, and measurement of colloid osmotic and arterial pressure were performed at predetermined times. Good results were obtained with equine albumin solution. More fluid is attracted into and maintained in the intravascular compartment, despite infusion of small volumes, as indicated by higher arterial pressure, lower capillary refill time, lower hematocrit and serum protein concentrations, lower colloid osmotic pressure, and better skin turgor. Equine albumin solution has good oncotic action and is a safe fluid therapy option for horses with colic and mild-to-moderate dehydration. Our results suggest it can be a good choice of fluid for correction of severe dehydration, although further research is necessary to determine the adequate dose in such cases.     

广州及其周边地区马梨形虫病血清流行病学调查

为广东从化无规定马属动物疫病区建设的顺利进行和了解周边地区马属动物马梨形虫病的存在情况,采用酶联免疫吸附试验(ELISA)和涂片镜检的方法对广州、东莞和深圳的马属动物进行了马梨形虫病(马巴贝斯虫和驽巴贝斯虫两种虫体)的流行病学调查。结果表明,上述三个地区的马属动物均存在不同程度的马梨形虫病两种虫体的抗体,且出现同一个马场和在同一匹马同时存在两种虫体抗体的情况。对所有抗体阳性马匹进行涂片镜检未发现虫体,也未发现有马梨形虫病临床症状的马属动物。