Bupivacaine is a long-acting local anesthetic that is used in various anesthetic and/or analgesic protocols, including intra-articular injection for pain management during orthopedic procedures. The purpose of this study was to evaluate the in vitro chondrotoxicity of bupivacaine at concentrations similar to in vivo synovial fluid concentrations in canine articular chondrocytes. A controlled in vitro experimental study was used. Third passage (P3) chondrocytes in monolayer culture were treated with bupivacaine at 0.25%, 0.125%, 0.062%, 0.031% and 0.016% (2.5, 1.25, 0.62, 0.31 and 0.16 mg/ml, respectively). The control was treated with only growth medium. Chondrocyte viability was evaluated after 1, 6 and 24 hr using the live/dead assay; 3-(4,5-dimehylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay; and Cell Counting Kit-8 (CCK-8) assay. Bupivacaine at 0.125% and 0.25% significantly decreased chondrocyte viability compared to the control at all treatment time-points (P < 0.001). Bupivacaine at 0.062% was chondrotoxic at all treatment time-points with the MTT assay (P < 0.001) but only after 6 and 24 hr with the live/dead and CCK-8 assays (P < 0.001). After 24 hr, 0.031% bupivacaine caused cell clustering with the live/dead assay and significantly decreased cell viability with the MTT (P < 0.001) and CCK-8 (P = 0.001) assays. Bupivacaine at 0.016% did not significantly decrease cell viability at any of the treatment time-points. These findings indicate that bupivacaine has in vitro chondrotoxic effects on canine articular chondrocytes at concentrations that are similar to in vivo synovial fluid concentrations, especially with prolonged exposure.

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The results of studies of morphological changes in the thyroid gland and the functional state of the organism of clinically healthy dogs living in the III zone of radioactive contamination (III RCZ) after a man-made accident at a nuclear power plant are presented. The aim of the work is to study the effect of prolonged radioactive radiation of caesium–137 radionuclides on changes in the morphofunctional state of the thyroid gland. Clinical, hematological, biochemical and pathomorphological studies of animals were carried out, the degree of radioactive contamination of water, feed, the background of the environment, the specific activity of gamma radiation of thyroid tissues were studied. The radiological indicators of the III zone of radioactive contamination are 3 times higher in terms of the power of the exposure dose of radiation and 6.8 times higher in terms of the specific activity of the diet and thyroid tissues. Abnormalities of adequate metabolism and functional activity of different systems were found in clinically healthy dogs. Signs of hypothyroidism were clinically identified in 28% of dogs. Laboratory studies have established hypochromic anemia, leucopenia, hypoalbuminemia, bilirubinemia, aspartate aminotransferase hyperfermentation, creatininemia, uremia, and cholesterolemia. In the hormonal profile, the level of triiodothyronine, thyroxine and thyroid-stimulating hormone was significantly reduced, which indicates the development of secondary hypothyroidism under the influence of caesium-137. Pathomorphological studies have determined hyperplasia of the organ, degenerative processes in functional structures – follicles, desquamation and degradation of thyrocytes, hemorrhages in the interfollicular tissue, which is the morphological equivalent of hypothyroidism.

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Recently, detection of canine primary adrenal mass has increased owing to progress in diagnostic imaging. Adrenocortical adenoma, adrenocortical carcinoma, and pheochromocytoma are representative primary adrenal masses; the latter two may invade intravascularly and metastasize to other organs. We encountered a dog exhibiting progressive hindlimb paraplegia. Multimodal imaging including computed tomography (CT) and magnetic resonance imaging (MRI) revealed that the cause of the paraplegia was infiltration of a left adrenal pheochromocytoma into the spinal canal. In addition, MRI detected small liver metastatic lesions that were not detected by CT.

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Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a cytokine that binds to fibroblast growth factor-inducible 14 (Fn14). The TWEAK/Fn14 pathway promotes intestinal inflammation, induces C-X-C motif chemokine ligand 10 (CXCL10), and is upregulated in the intestine of humans with inflammatory bowel disease. However, the role of this pathway in canine chronic enteropathy (CE) remains unclear. Therefore, we measured TWEAK, Fn14, and CXCL10 mRNA levels in the intestinal mucosa of dogs with CE. Real-time PCR analysis revealed significantly lower TWEAK and CXCL10 mRNA levels in the duodenal mucosa of dogs with antibiotic-responsive enteropathy (ARE), a type of CE, compared to healthy dogs. The findings suggested the involvement of decreased TWEAK and CXCL10 mRNA levels in the ARE etiology.

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