Seok Hwa Choi

Porous hydroxyapatite scaffold with three-dimensional localized drug delivery system using biodegradable microspheres

In this study, ionic immobilization of dexamethasone (DEX)-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres was performed on the hydroxyapatite (HAp) scaffold surfaces. It was hypothesized that in vivo bone regeneration could be enhanced with HAp scaffolds containing DEX-loaded PLGA microspheres compared to the use of HAp scaffolds alone. In vitro drug release from the encapsulated microspheres was measured prior to the implantation in the femur defects of beagle dogs. It was observed that porous, interconnected HAp scaffolds as well as DEX-loaded PLGA microspheres were successfully fabricated in this study. Additionally, PEI was successfully coated on PLGA microsphere surfaces, resulting in a net positive-charged surface. With such modification of the PLGA microsphere surfaces, DEX-loaded PLGA microspheres were immobilized on the negatively charged HAp scaffold surfaces. Release profile of DEX over a 4week immersion study indicated an initial burst release followed by a sustained release. In vivo evaluation of the defects filled with DEX-loaded HAp scaffolds indicated enhanced volume and quality of new bone formation when compared to defects that were either unfilled or filled with HAp scaffolds alone. This innovative platform for bioactive molecule delivery more potently induced osteogenesis in vivo, which may be exploited in implantable bone graft substitutes for stem cell therapy or improved in vivo performance. It was thus concluded that various bioactive molecules for bone regeneration might be efficiently incorporated with calcium phosphate-based bioceramics using biodegradable polymeric microspheres.

Comparison of the cytotoxic effects of bupivacaine, lidocaine, and mepivacaine in equine articular chondrocytes

OBJECTIVEnTo compare the chondrotoxicity of bupivacaine, lidocaine, and mepivacaine in equine articular chondrocytes in vitro.nnnSTUDY DESIGNnProspective, experimental study.nnnSTUDY MATERIALnEquine articular chondrocytes.nnnMETHODSnPrimary cultured equine chondrocytes were exposed to 0.5% bupivacaine, 2% lidocaine, or 2% mepivacaine for 30 or 60 minutes. After treatment, cell viability was evaluated by trypan blue exclusion and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay in a dose dependent manner. Apoptosis and necrosis of chondrocytes were analyzed with the double staining of Hoechst 33258 and propidium iodide using fluorescence microscopy, and the results were confirmed using flow cytometry.nnnRESULTSnAfter 30-minute exposure, trypan blue exclusion assay revealed that cell viability of 0.5% bupivacaine group was 28.73±8.44%, and those of 2% lidocaine and 2% mepivacaine were 66.85±6.03% and 86.27±2.00%, respectively. The viability of chondrocytes after saline treatment was 95.95±2.75%. The results of MTT assay and fluorescence microscopy had similar tendency with trypan blue assay. Each result showed that bupivacaine was the most toxic of the three local anaesthetics. Mepivacaine was less toxic than lidocaine. The results of the viability test suggest that bupivacaine and lidocaine exhibit a marked chondrotoxicity, and that this is mainly due to necrosis rather than apoptosis.nnnCONCLUSIONS AND CLINICAL RELEVANCEnBupivacaine may induce detrimental chondrotoxicity when administered intra-articularly, especially in patients with joint disease, and we suggest that it should be used cautiously in equine practice. Mepivacaine may be an alternative to both bupivacaine and lidocaine.

The distribution and requirements of microtubules and microfilaments in bovine oocytes during in vitro maturation.

Microtubules and microfilaments are major cytoskeletal components and important modulators for chromosomal movement and cellular division in mammalian oocytes. In this study we observed microtubule and microfilament organisation in bovine oocytes by laser scanning confocal microscopy, and determined requirements of their assembly during in vitro maturation. After germinal vesicle breakdown, small microtubular asters were observed near the condensed chromatin. The asters appeared to elongate and encompass condensed chromatin particles. At the metaphase stage, microtubules were observed in the second meiotic spindle at the metaphase stage. The meiotic spindle was a symmetrical, barrel-shaped structure containing anastral broad poles, located peripherally and radially oriented. Treatment with nocodazole did not inhibit germinal vesicle breakdown. However, progression to metaphase failed to occur in oocytes treated with nocodazole. In contrast, microfilaments were observed as a relatively thick uniform area around the cell cortex and overlying chromatin following germinal vesicle breakdown. Treatment with cytochalasin B inhibited microfilament polymerisation but did not prevent either germinal vesicle breakdown or metaphase formation. However, movement of chromatin to the proper position was inhibited in oocytes treated with cytochalasin B. These results suggest that both microtubules and microfilaments are closely associated with reconstruction and proper positioning of chromatin during meiotic maturation in bovine oocytes.

The Effect of Whole Bee Venom on Arthritis

This study was performed to assess the clincotherapeutic effect of whole venom of honeybee (Apis mellifera) in adjuvant-induced arthritic rat. Ninety Sprague-Dawley male rats were injected with complete Freunds adjuvant (CFA). Adjuvant arthritis was produced by a single subcutaneous injection of I mg Mycobacterium butyricum suspended in 0.1 ml paraffin oil into the right hind paw. Righting reflex was uniformly lost and considered to be the point of arthritis development on day 14 after CFA injection. The experiments were divided into three groups. When arthritis was developed in the rat, tested groups were administered with prednisolone (10 mg/kg, p.o.) or honeybee venom (one bee, s.c.) every other day for another 14 days. Control group was injected with 0.1 ml of physiological saline solution subcutaneously. Clinical and hematological values with histopathological findings were observed during the drug administration. In treatment groups, the development of inflammatory edema and polyarthritis was suppressed. No significant differences of hind paw edema volume and lameness score between prednisolone and honeybee venom groups were observed during treatment. White blood cell counts of control group showed leucocytosis that was significantly different from the two treatment groups (p < 0.01). Erosions of articular cartilage and inflammatory cell infiltrations into interphalangeal joint were effectively suppressed in treated groups. In conclusion, whole honeybee venom was found to suppress arthritic inflammation in the rat. This may be an alternative treatment of arthritic agony in humans.

The effects of enrofloxacin on canine tendon cells and chondrocytes proliferation in vitro

Enrofloxacin, a fluoroquinolone antibiotic has been used widely in humans and domestic animals, including dogs, because of its broad-spectrum activity and relative safety. The side effects of fluoroquinolone, induced tendinopathy, tendonitis, spontaneous tendon rupture and cartilage damage, remain incompletely understood. In the present study, we investigated the in vitro effects of enrofloxacin on cell proliferation and induction of apoptosis in canine Achilles tendon cells and chondrocytes. Cell growth and proliferation after treating with enrofloxacin for 2–6xa0days was quantified by a colorimetric 2,3-bis{2-methoxy-4-nitro-5-sulfophenyl}-2H-tetrazolium-5-carboxyanilide inner salt (XTT) assay. The results showed that enrofloxacin could inhibit the proliferation of canine tendon cells and chondrocytes at increasing concentrations (10–200xa0μg/ml). The inhibition of proliferation of canine tendon cells and chondrocytes after exposure to enrofloxacin were associated with induction of apoptosis, as evidenced by the typical nuclear apoptotic condensed nuclei found using Hoechst 33258 staining. It was demonstrated that canine tendon cells and chondrocytes treated with 200xa0μg/ml enrofloxacin for 4xa0days exhibited apoptotic features and fragmentation of DNA. Enrofloxacin also increased the apoptosis of canine tendon cells and chondrocytes in a dose and time-dependent manner. The results indicate that enrofloxacin inhibits cell proliferation, induces apoptosis and DNA fragmentation, which might explain enrofloxacin-induced tendinopathy and cartilage damage.

Effect of apitherapy in piglets with preweaning diarrhea.

This study was designed to examine the therapeutic effect of honeybee (Apis mellifera L.) venom in piglets with bacterial diarrhea Comparison between bee venom- and drug-treated groups was our main concern in the present study. Preweaning piglets were assigned to treated and non-treated control groups. In the treated group, 47 piglets were acupunctured with the worker honeybee once a day for three consecutive days. Two acupoints, GV-1 (Jiao-chao) and ST-25 (Hai-men), were selected for apitherapy. In the control group, 44 piglets were intramuscularly injected with a standard dose of a known antibacterial drug, colistin sulfate (300,000 IU/kg of body weight), and an antidiarrheal drug (berberine, 2 ml/kg) once a day for three consecutive days. At post-treatment, 90.9% of the control piglets and 93.6% of piglets in the treated group recovered from bacterial diarrhea. Bee acupuncture therapy did not show any side effects such as allergy, intoxication, hemorrhage or infection. It is concluded that bee venom therapy was effective in controlling bacterial diarrhea in preweaning piglets.

Additive Effects of Intra-articular Injection of Growth Hormone and Hyaluronic Acid in Rabbit Model of Collagenase-induced Osteoarthritis

In a rabbit model of collagenase-induced osteoarthritis, the additive effects of intra-articular recombinant human growth hormone (GH) administration to hyaluronic acid (HA) were evaluated. After intra-articular collagenase injection, mature New Zealand white rabbits (n=30) were divided into 3 groups. Group 1 (control rabbits) received once weekly intra-articular saline injections for 4 weeks. Group 2 rabbits received 6 mg HA injections, and group 3 rabbits were injected with 6 mg HA and 3 mg recombinant human GH. These injections were initiated 4 weeks after collagenase injections. Lameness was observed for 9 weeks after collagenase injections. Macroscopic and histopathological knee joint findings were also evaluated at the end of 9 weeks after collagenase injections. Although all animals had lameness after collagenase injections, the duration and severity of lameness were significantly shorter and less severe in group 3 than group 1 and 2 (P<0.01). Macroscopic scores showed that femoral condyles of group 3 rabbits received significantly less cartilage damage than those of groups 1 and 2 rabbits (P<0.01). Histopathological score was also the lowest in group 3 (P<0.01). These results suggest that co-injection of intra-articular HA and recombinant human GH is more effective than HA injections alone in an osteoarthritis model.

Ethanol Extract of Magnolia officinalis Prevents Lipopolysaccharide-Induced Memory Deficiency via Its Antineuroinflammatory and Antiamyloidogenic Effects

Magnolia bark contains several compounds such as magnolol, honokiol, 4‐O‐methylhonokiol, obovatol, and other neolignan compounds. These compounds have been reported to have various beneficial effects in various diseases. There is sufficient possibility that ethanol extract of Magnolia officinalis is more effective in amyloidogenesis via synergism of these ingredients. Neuroinflammation has been known to play a critical role in the pathogenesis of Alzheimers disease (AD). We investigated whether the ethanol extract of M.u2009officinalis (10u2009mg/u2009kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis in AD mouse model by intraperitoneal lipopolysaccharide (LPS, 250u2009µg/u2009kg/day for seven times) injection. We found that ethanol extract of M.u2009officinalis prevented LPS‐induced memory deficiency as well as inhibited the LPS‐induced elevation of inflammatory proteins, such as inducible nitric oxide synthase and cyclooxygenase 2, and activation of astrocytes and microglia. In particular, administration of M.u2009officinalis ethanol extract inhibited LPS‐induced amyloidogenesis, which resulted in the inhibition of amyloid precursor protein, beta‐site amyloid‐precursor‐protein‐cleaving enzyme 1 and C99. Thus, this study shows that ethanol extract of M.u2009officinalis prevents LPS‐induced memory impairment as well as amyloidogenesis via inhibition of neuroinflammation and suggests that ethanol extract of M.u2009officinalis might be a useful intervention for neuroinflammation‐associated diseases such as AD. Copyright

Clinical effect of additional electroacupuncture on thoracolumbar intervertebral disc herniation in 80 paraplegic dogs.

The clinical efficacy of electroacupuncture and acupuncture in combination with medication for the treatment of thoracolumbar intervertebral disc herniation was investigated in paraplegic dogs with intact deep pain perception. To evaluate the additional effect of electroacupuncture, dogs treated with conventional medicines alone were compared to dogs treated with electroacupuncture and acupuncture and conventional medicine. Medical records of 80 dogs were reviewed for this investigation and classified into two groups undergoing different treatment methods: (1) treatment with conventional medicine alone (Group C, n = 37) and (2) treatment with conventional medicine combined with electroacupuncture and acupuncture (Group CE, n = 43). Prednisone was the conventional medicine and electroacupuncture was applied at GV07 and GV02-1 at 0.5-2.5 mV, mixed Hz of 2 and 15 Hz for 25-30 min. Acupuncture was performed locally at urinary bladder meridian points near the lesion, and bilaterally distantly at GB30, GB34, and ST36. Treatment efficacy was evaluated by post-operative neurologic function, ambulation, relapse, complication, and urinary function. Ambulation recovery was more prevalent in Group CE than Group C (p = 0.01) and recovery of ambulation and back pain relief time was shorter in Group CE compared to Group C (p = 0.011 and 0.001, respectively). Relapse rate was significantly lower in Group CE (p = 0.031). The results suggest that a combination of electroacupuncture and acupuncture with conventional medicine is more effective than conventional medicine alone in recovering ambulation, relieving back pain, and decreasing relapse. Electroacupuncture and acupuncture is thus a reasonable option for the treatment of intervertebral disc herniation in paraplegic dogs with intact deep pain perception.

The Effects of α-Viniferin on Adjuvant-Induced Arthritis in Rats

This study was performed to assess the efficacy of α-viniferin (Carex humilis Leyss) on adjuvant-induced arthritis in rats. Adjuvant arthritis was induced by a single subcutaneous injection of 0.1 ml complete Freunds adjuvant (CFA) containing 7.5 mg Mycobacterium butyricum suspended in 1 ml sterile paraffin oil into the right hind paw. Forty female Sprague-Dawley rats were injected. Righting reflex was uniformly lost and considered to be the initial point of arthritis development on day 7 after CFA injection. Rats were divided into four groups, and upon development of arthritis, tested groups were orally administered 3 or 10 mg/kg α-viniferin or 10 mg/kg ketoprofen every day for 14 days. The control group was orally administered 2 ml of physiological saline solution. Bone mineral density (BMD), radiological changes and edematous volumes were measured for 35 days. α-viniferin suppressed the development of inflammatory edema, and inhibited the bone destruction, noted with a decrease in BMD (p<0.05). Hind paw edema volume, BMD and radiological changes did not differ significantly in the ketoprofen and α-viniferin groups during the entire study period. In conclusion, α-viniferin suppressed arthritic inflammation and bony change in rats.