Although hyaluronic acid (HA) has been developed as a nanoparticle (NP; 320-400 nm) for a drug delivery system, the tissue targeting efficacy and the pharmacokinetics of HA-NPs are not yet fully understood. After a dose of 5 mg/kg of cyanine 5.5-labeled HA-NPs or HA-polymers was intravenously administrated into mice, the fluorescence was measured from 0.5 h to 28 days. The HA-NPs fluorescence was generally stronger than that of HA-polymers, which was maintained at a high level over 7 days in vivo, after which it gradually decreased. Upon ex vivo imaging, liver, spleen, kidney, lung, testis and sublingual gland fluorescences were much higher than that of other organs. The fluorescence of HA-NPs in the liver, spleen and kidney was highest at 30 min, where it was generally maintained until 4 h, while it drastically decreased at 1 day. However, the fluorescence in the liver and spleen increased sharply at 7 days relative to 3 days, then decreased drastically at 14 days. Conversely, the fluorescence of HA-polymers in the lymph node was higher than that of HA-NPs. The results presented herein may have important clinical implications regarding the safety of as self-assembled HA-NPs, which can be widely used in biomedical applications.

Temporal and subcellular distributions of hyaluronic acid (HA) as a degradable nanoparticle (NP) in animals were investigated to determine if HA-NP could be utilized as an appropriate drug delivery system. After mice were intravenously injected with 5 mg/kg of Cy5.5-labeled HA-NP sized 350-400 nm or larger HA-polymers, the fluorescence intensity was measured in all homogenized organs from 0.5 h to 28 days. HA-NP was greatly detected in spleen, liver and kidney until day 28, while it was maintained at low levels in other organs. HA-polymer was observed at low levels in all organs. HA-NP quantities in spleen and liver were reduced until day 3, but increased sharply between days 3 and 7, then decreased again, while their HA-polymers were maintained at low levels until day 28. In kidneys, both HA-NP and HA-polymer showed high levels after 0.5 h of administration, but steadily decreased until day 28. According to ultrastructural analyses, HA-NP was engulfed in Kupffer cells of liver and macrophages of spleen and kidney at day 1 and was accumulated in the cytoplasm of kidney tubular cells at day 7. Overall, these findings suggest that HA-NP could be considered a desirable drug carrier in the liver, kidney, or spleen.

The only way to diagnose hepatic fibrosis in dogs is by histological assessment of a liver biopsy specimen. As this technique is invasive and susceptible to sampling variation, serum biomarkers are used to detect hepatic fibrosis in humans. The objective of this study was to assess the utility of hyaluronic acid (HA), procollagen type III N-terminal peptide (PIIINP), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) as serum markers of canine hepatic fibrosis. Serum samples were collected from 47 dogs with histologically confirmed hepatobiliary disease and 24 healthy dogs in order to measure concentrations of HA, PIIINP, and TIMP-1. Hepatic fibrosis was staged using a 5-point scoring scheme. There was no correlation between serum concentrations of HA or PIIINP and the severity of hepatic fibrosis. There was a negative correlation between serum concentration of TIMP-1 and the severity of hepatic fibrosis (r s = −0.33; P = 0.036). It was not possible to use serum concentrations of HA, PIIINP, or TIMP-1 to discriminate between dogs with absent-to-moderate hepatic fibrosis and those with marked-to-very-marked fibrosis. The results of this study do not support the utility of measuring serum concentrations of HA, PIIINP, or TIMP-1 for diagnosing canine hepatic fibrosis. Further studies are needed to support this finding.

Objective-To determine the effects of recombinant equine interleukin -1beta (reIL-1beta) and 4 anti-inflammatory compounds on the expression and activity of cyclooxygenase (COX)-2 in cultured equine chondrocytes. Sample Population-Articular cartilage from 9 young adult horses. Procedure-Reverse transcriptase-polymerase chain reaction methods were used to amplify a portion of equine COX-2 to prepare a cDNA probe. Northern blot analysis was used to quantify the expression of COX-2 in first-passage cultures of equine articular chondrocytes propagated in media containing dexamethasone (DEX), phenylbutazone (PBZ), polysulfated glycosaminoglycan, and hyaluronan, each at concentrations of 10 and 100 micrograms/ml and each with or without reIL-1beta. A commercial immunoassay was used to determine prostaglandin E2 (PGE2) concentrations in conditioned medium of similarly treated cells to quantify COX-2 activity. Results-Addition of reIL-1beta increased the expression of COX-2 in a dose-dependent manner, which was paralleled by an increased concentration of PGE2 in culture medium. Concentration of PGE2 in spent medium from reIL-1beta-treated chondrocytes was significantly reduced by DEX and PBZ; however, only DEX significantly reduced gene expression of COX-2. Conclusions and Clinical Relevance-Prostaglandin E2 is considered to be an important mediator in the pathophysiologic processes of arthritis, and cultured chondrocytes respond to interleukin-1 with enhanced expression and activity of COX-2. Palliative relief in affected horses is probably attributable, in part, to inhibition of PGE2 synthesis; however, analysis of these data suggests that of the 4 compounds tested, only DEX affects pretranslational regulation of the COX-2 gene in cultured equine chondrocytes.

Physical, biochemical, and cytologic properties of synovial fluid from digital flexor tendon sheaths of clinically normal horses were investigated. Tendon sheath fluid was pale yellow, clear, and did not clot. Volume of fluid within a tendon sheath varied minimally, with a mean of 2.11 ml. Total erythrocyte counts were higher than values observed in normal equine joint fluid, whereas values for total leukocyte count (770 +/- 73 cells/mm3), viscosity (6.05 +/- 0.58 cs), and protein concentration (7.87 +/- 0.03 mg/ml) were similar to those in joint fluid. Large mononuclear cells were the predominant synovial fluid cell type. Mean hyaluronic acid concentration (0.74 +/- 0.02 mg/ml) and mucinous precipitate quality were lower than values in joint fluid.

Intraocular pressure (IOP) was determined in right eyes of 20 healthy dogs after sodium hyaluronate (1%, n = 5), sodium chondroitin sulfate (4%) and sodium hyaluronate (3%, n = 5), hydroxypropyl methylcellulose (2%, n = 5), or balanced salt solution (control, n = 5) was injected into the anterior chamber. Applanation tonometry was used to measure IOP in both eyes of each dog for up to 168 hours. The 3 viscoelastic solutions resulted in an increased mean IOP by postinjection hours (PIH) 2; from PIH 12 until PIH 72, the IOP was significantly (P less than 0.001) lower than baseline. The control group did not have an increase in IOP at PIH 2; mean IOP decreased below baseline measurements within 2 hours and remained lower until PIH 72. Mean differences in IOP were not found among treated eyes (P = 0.50), and a significant interaction of any treated eyes in a group was not detected (P = 0.21). By PIH 168, the IOP approached baseline values in all groups.

This study was conducted to investigate the effect of hyaluronic acid (HA) on prevention of abdominal adhesions depending on various concentrations thereof by inducing an abrasion experimentally in the cecum of rats. Each group was consisted of 10 rats, and 40 rats were divided into 4 groups comprising the saline treatment group, HA 0.4% treated group, 0.6% treated group, and 0.8% treated group. And abrasion was caused in the cecum by using dry gauze and thereby, adhesion was induced. On 7 days after the operation, adhesions of each region were evaluated into the range of 0~4.

Several new topical products have been applied to enhance wound healing and reduce scar formation. The present study aimed to evaluate the potential of the topically applied hyaluronic acid (HA) serum and chitosan (CH) gel for skin wound healing in dogs. Ten adult mongrel dogs were divided into two groups (n = 5 for each). Experimental skin wounds were created in all animals. Eight full-thickness round skin wounds of 2 cm diameter were made on both sides (four for each side) over the dog's dorsal area, where the left side wounds were kept as a control and treated with saline solution only. HA serum and CH gel were used to treat the right-side wounds in the first and second groups, respectively. Wound healing was evaluated clinically and histologically at the 7th, 14th, and 21st days post-treatment. In addition, the tensile strength was measured in both treated wound groups and compared with the control wounds and the normal skin. The results showed that HA-treated wounds exhibited higher wound contraction and better tensile strength compared with CH-treated group. In addition, the histological findings of HA-treated wounds showed marked improvement in histological repair scores compared with CH-treated ones. We concluded that topical HA in a serum formulation provided better skin wound healing compared to CH-treated group.

OBJECTIVE To evaluate lameness and morphological changes associated with an osteochondral fragment–groove procedure as a means of experimental induction of metacarpophalangeal (MCP) joint osteoarthritis within an 11-week period in horses. ANIMALS 6 nonlame adult warmbloods. PROCEDURES The right MCP joint of each horse underwent an osteochondral fragment–groove procedure (day 0). After 1 week of stall rest (ie, starting day 7), each horse was trained daily on a treadmill. Weekly, horses underwent visual and inertial sensor-based assessments of lameness. Both MCP joints were assessed radiographically on days 0 (before surgery), 1, 35, and 77. A synovial fluid sample was collected from the right MCP joint on days 0 (before surgery), 35, 36, 49, 63, and 77 for cytologic and biomarker analyses. On day 77, each horse was euthanized; both MCP joints were evaluated macroscopically and histologically. RESULTS Right forelimb lameness was detected visually and by the inertial sensor system when horses were moving on a straight line after distal forelimb flexion or circling left on days 14 to 77. Compared with presurgical values, synovial fluid interleukin-6, prostaglandin E2, hyaluronic acid, and interleukin-1 receptor antagonist protein concentrations were increased at 2 or 3 time points, whereas tumor necrosis factor-α and interleukin-10 concentrations were decreased at 1 time point. Gross examination of all right MCP joints revealed synovitis and wear lines; synovitis was confirmed histologically. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a combined osteochondral fragment–groove procedure can be used to induce clinically and grossly observable early MCP joint osteoarthritis during an 11-week period in horses.