Pig tracheal patchy xenotransplantation in the dog.

BACKGROUND: A long-segmental tracheal lesion is difficult to repair by tracheal allotransplantation due to the lack of a well-defined blood supply for blood vessel anastomosis. The donor trachea needs to be revascularized within a well-vascularized soft tissue flap for several months to allow successful trachea allotransplantation. To date, xenotransplantation using the wild-type or genetically modified pig has been widely studied. The object of this study was to evaluate the feasibility of a small-sized (2 × 2 cm) wild-type pig tracheal patchy in a dog tracheal defect model before trying a long-segment tracheal defect model and using a genetically modified pig as a donor in dog xenotransplantation. METHOD: Three healthy beagle dogs (8-9 kg) were used as recipients, and one pig (20 kg) was used as the donor. A pig cartilaginous tracheal patchy (2 × 2 cm half tube) was sutured to the tracheal resected site in each dog. Antithymocyte globulin (2.5 mg/kg infusion, D0 and 1), tacrolimus (4.5 mg/kg, twice a day for 2 months), and methylprednisolone sodium succinate (1 mg/kg, IV, for 2 days and tapering) were administered for immunosuppression. The levels IL-2 and IFN-γ in the serum were measured at D0, 7, and 28. Tracheoscopy was performed at D28, 60, and 90. The recipients were sacrificed at D90, and the expression of dog and pig genes in the graft was evaluated by PCR. Histopathological examination of the graft was conducted. RESULTS: All of the dogs survived without complications during the experimental period. Their IL-2 and IFN-γ levels were significantly increased at D7 after transplantation compared to D0 and D28 (P < 0.05). The pig tracheal patchy site was open, and no stenosis was observed until D90 on tracheoscopy, when pale mucosa erosion was observed; there was also remnant suture material at D28. However, the tracheal patchy sites gradually became similar to normal mucosa at D60 and 90. The expression of pig genes was detected in the graft by PCR. Normal epithelium and CD3 cells were observed in the histological examination at D90. CONCLUSION: In this study, our data suggest that the pig tracheal patchy can be successfully engrafted into the trachea of dog, although erosion of mucosa on the graft was seen at D30, in spite of the discordant species.

In Vitro Evaluation of Hydroxyapatite-Coated Titanium Implant with Atmospheric Plasma Treatment.

Plasma treatments are becoming a popular method for modifying the characteristics of a range of substrate surfaces. Atmospheric pressure plasma (APP) is cost-efficient, safe and simple compared to high-pressure plasma. This study examined the effects of a low-temperature APP treatment of a hydroxyapatite (HA)-coated Ti (HA-Ti) surface. The APP treatment made the HA-Ti surfaces more hydrophilic without changing surface morphologies. The APP-treated HA-Ti (APP-HA-Ti) surface showed enhanced cell spreading, cell proliferation, and alkaline phosphatase (ALP) levels with more developed cellular networks, and the formed extracellular matrix (ECM) was fused perfectly with the HA substrate than that on the HA-Ti surface. In conclusion, an APP treatment is a potential surface-modifying method that can enhance the cell affinity at the early stages in vitro.

Antibacterial releasing titanium surface using albumin nanoparticle carriers.

We developed a simple and highly efficient method for delivery from titanium (Ti) surfaces using albumin nanoparticle carriers. A Ti disc with a resorbable blasting media surface was used as a metal implant with a localized drug delivery structure. Human serum albumin (HSA) nanoparticles loaded with chlorhexidine (CHX) diacetate salt hydrate as the model drug were fabricated using a desolvation technique. The CHX-loaded HSA nanoparticles produced were cross linked with glutaraldehyde (GA). The nanoparticles were pre-coated with positively-charged polyethylenimine (PEI) molecules and then immobilized via electrical interactions on the negatively charged Ti disc surface. Our results suggested that the PEI-coated HSA nanoparticles loaded with CHX (PEI-CHX-HSA) were incorporated successfully and well-dispersed on the Ti disc surfaces. The agar diffusion test on the Ti surface treated with PEI-CHX-HSA nanoparticles showed a larger growth inhibition zone of Streptococcus mutans versus the control Ti surface, suggesting that this innovative delivery platform imparts potent antibacterial activity to the Ti surface. Thus, CHX, which inhibits the growth of oral bacteria, can be efficiently incorporated onto Ti surfaces by using HSA nanoparticles.

Comparison of endoscopic band ligation and endoclip closure of colonic perforation: technical feasibility and efficacy in an ex vivo pig model.

BACKGROUND AND AIM: Recent reports have indicated several instances of successful treatment of bowel perforation by using endoscopic band ligation (EBL) when treatment with endoclipping is unsuccessful, but this salvage method has not been investigated in any prospective model. Herein we aimed to compare the technical feasibility and efficacy of EBL and endoclip use in intraluminal closure of colon perforation, in an ex vivo model. METHODS: Standardized colonic perforations were created using fresh porcine colon and subsequently closed by full-thickness interrupted sutures, endoclip (QuickClip2(TM)), or EBL. Each closure site was tested with compressed air by using a digital pressure monitor for evaluating leak pressure. RESULTS: No significant differences were noted between the endoclip and EBL in leak pressures. Mean (± SD) pressures for air leakage from the perforations closed using the different devices were as follows: normal colon samples, 52.0 ± 13.2 mmHg; perforations closed with hand-sewn sutures, 32.3 ± 8.3 mmHg; perforations closed with endoclipping, 53.5 ± 22.7 mmHg; and perforations closed with EBL, 50.4 ± 12.5 mmHg. Time taken for closure by EBL was significantly less than that for closure by endoclipping (3.2 ± 1.7 min vs 6.8 ± 1.3 min, P < 0.01). Further, the number of devices used to achieve complete closure in the EBL group was lower than that with endoclipping (1.6 ± 0.5 vs 3.7 ± 0.8, P < 0.01). CONCLUSION: Endoluminal closure of a 1.5-cm colon perforation with EBL decreased procedure time and was not inferior in leak pressure compared with endoclipping in this ex vivo porcine 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 Alzheimer's disease (AD). We investigated whether the ethanol extract of M. officinalis (10 mg/ kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis in AD mouse model by intraperitoneal lipopolysaccharide (LPS, 250 µg/ kg/day for seven times) injection. We found that ethanol extract of M. officinalis 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. officinalis 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. officinalis prevents LPS-induced memory impairment as well as amyloidogenesis via inhibition of neuroinflammation and suggests that ethanol extract of M. officinalis might be a useful intervention for neuroinflammation-associated diseases such as AD.

Clinical Usefulness of Shoulder Stability Exercises for Middle-aged Women.

[Purpose] This study examined the clinical usefulness of shoulder stability exercises and the effect of stability exercise on the shoulder pain of middle-aged women. [Subjects] Twenty-two middle-aged female subjects were randomly divided into two groups: a shoulder stability exercise group (Experimental group, n=11) and a control group (n=11). [Methods] Subjects in the experimental group performed a shoulder stability exercise, which was designed to correct abnormal location of the scapula, for 40 minutes per day, three times per week, over a period of four weeks. Range of motion, muscle strength, and grasping power were measured to determine the effect of the shoulder stability exercise. The measured parameters were evaluated before and after four weeks of exercise. [Results] Following intervention, range of motion, muscle strength, and grasping power showed greater improvements in the experimental group than in the control group. [Conclusion] The results of this study show that shoulder stability exercise can improve the shoulder function of middle-aged women, and prevent damage to the shoulder joint. We consider this exercise would be useful in clinical rehabilitation.

Are Veterinary Costs and Socioeconomic Status Risk Factors for Companion Animal Relinquishment in the Republic of Korea?

More than 110,000 companion animals are sent to shelters each year due to abandonment in Republic of Korea, and there is a need to analyze the causes of the relinquishment of animals and implement appropriate policies. Veterinary costs have been blamed for this issue in Republic of Korea above the reported leading causes of socioeconomic status of owners, cost and behavior issues of the animals, or housing restrictions. However, it is rare to find supporting evidence. In this study, we aimed to determine whether veterinary costs and socioeconomic factors are related to animal relinquishment in Republic of Korea. Multiple regression models were used to test if veterinary costs and socioeconomic indicators can account for relinquishment in 128 regions of Republic of Korea in 2020 and 2021. When five independent variables (two veterinary cost data and three socioeconomic indicators) were included, the regression model showed significance in explaining pet relinquishment in 2020, with an adjusted coefficient of determination of 0.3956. Pet relinquishment can also be explained by the same five variables for 2021, with an adjusted coefficient of determination of 0.391 with p < 0.0001. The findings suggest that intervention to reduce companion animal relinquishment in Republic of Korea should focus on lightening the financial burdens of owners as the socioeconomic status of a community worsens.

Evaluation of Biomechanical Properties and Morphometric Structures of the Trachea in Pigs and Rabbits.

BACKGROUND/AIM: Animals differ in the biochemical composition, attachments, and mechanical properties of tracheal cartilage. This study examined the biomechanical properties and morphological structure of the trachea of pigs, and rabbits as preclinical models. MATERIALS AND METHODS: The trachea in pigs and rabbits can be divided into four regions, cranial cervical, middle cervical, thoracic inlet, and intra-thoracic parts. RESULTS: The total number of tracheal rings in pigs and rabbits was 32-35 and 34-38 rings, respectively. The pig bronchus first branches from the trachea, reaching the cranial lobe of the lungs before branching to the main bronchus, while the rabbit bronchus branched after the main bronchus. A comparison of the posterior region of the crosssectional trachea shows that the rabbit has a C-shape with cartilage connected to the tracheal muscle, and the pig has the tracheal muscle covered with cartilage. The trachea of pigs and rabbits decreased in tracheal thickness and size from the thoracic inlet toward the lungs. The stress-strain in the longitudinal and transverse tensile test was higher in rabbits than in pigs. The tensile stress of the four regions was significantly different in the transverse tensile test (p<0.001). In the bending test, more force was required to bend pig than rabbit tracheas. Microscopic and scanning electron microscopy showed no structural differences in tracheal cartilage between the two species. CONCLUSION: These results suggest that there is great variation in morphology and physical properties of the trachea in pigs and rabbits. We found porcine tracheas have similar biomechanical properties to those of humans.

Assessment of Individual Renal Function Using 99mTc-MAG3 Renography.

BACKGROUND/AIM: This study performed 99mTc-MAG3 renal scintigraphy on rabbit kidneys and evaluated its ability to identify obstructive or non-obstructive kidneys. MATERIALS AND METHODS: Renal function was assessed during a four-week post-obstruction period by obtaining planar images of 99mTc-MAG3 activity following an ear vein injection. The individual renal function was evaluated by renal scintigraphy in conjunction with histopathological and morphological examinations. RESULTS: The renal perfusion of 99mTc-MAG3 in the right kidney with a ureteral obstruction decreased with time. The width, height, and cortical thickness of the obstructed right kidney were significantly larger than those of the left kidney. A histopathological examination four weeks after the ureteral obstruction revealed a typical pattern of urinary tract obstruction, including multiple tubules, enlargement of the interstitial area, and cytoplasmic vacuoles. CONCLUSION: 99mTc-MAG3 renal scintigraphy provides the kidney shape and size and can identify potential obstructive and non-obstructive kidneys in rabbits.

Anti-obesity Effects of Dark Tea Extracts by Down-regulation of C/EBPα and PPARγ.

BACKGROUND/AIM: Dark tea, made by fermentation of tea leaves using microorganisms, is well known for its antiobesity effect; however, studies to identify this effect have not been sufficiently conducted. Herein, the anti-obesity effects of post-fermented dark tea were studied in high-fat diet mouse. MATERIALS AND METHODS: Obesity was induced through a high-fat diet in C57BL/6 mice, and then dark tea extract powder (DTP) was orally administered daily for 12 weeks to evaluate the body and organ weights. Changes in the biochemical markers of obesity were evaluated to study the mechanism of the anti-obesity effects of DTP. RESULTS: When DTP was administered to obesity mice, the weight and food intake reduced, blood aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C) decreased, whereas high-density lipoprotein cholesterol (HDL-C) increased. Histopathology showed that steatosis and inflammation scores were reduced within the liver and adipocyte sizes were reduced within epididymal adipocyte. In addition, a significant decrease in blood insulin and hepatic TG and a significant increase in blood adiponectin were also confirmed. The results of western blot and qPCR in week 12, showed a significant decrease in the mRNA and protein levels of C/EBPα, and the mRNA levels of PPARγ in the liver. CONCLUSION: Dark tea extracts are thought to have an anti-obesity effect by reducing the levels of the main transcription factors that promote adipocyte differentiation, such as C/EBPα, and PPARγ. Therefore, diet products using dark tea extracts could be developed.

Bone regeneration of tibial segmental defect using isotropic-pore structures hydroxyapatite/alumina bi-layered scaffold: in vivo pilot study.

Bone defects resulting from trauma or pathology represent a common and significant clinical problem. In this study, hydroxyapatite (HAp)-alumina bi-layered scaffolds, which have the benefits of both HAp (i.e., osteointegration, osteoconduction) and alumina (i.e., hardness) were used as a bone substitute for the repair of large segmental defects (20 mm) created in a beagle tibia model. Highly porous bi-layered scaffolds with isotropic-pore structures were fabricated using a polymer-template coating technique. The pore sizes obtained using this approach ranged between 230 µm and 470 µm, and porosity was 91.61±1.28%. Using scanning electron microscopy and energy dispersive spectroscopy, it was confirmed that the frame of each bi-layered scaffold consisted of an alumina inner layer and HAp outer layer. The evaluation of bone regeneration within each scaffold after implantation in the beagle tibia was performed using CT, micro-CT, scintigraphy. New bone formation was evident in the large segmental defects treated with HAp/alumina scaffolds. It was concluded from this study that the HAp/alumina bi-layered scaffold is instrumental in inducing host-scaffold engraftment at the distal and proximal ends of the defect as well as distributing the newly formed bone throughout each scaffold 8 weeks post-implantation.

Intraluminal Titanium Alloy Stent to Prevent Tracheal Stenosis in Tracheal Anastomosis.

BACKGROUND/AIM: Tracheal stenosis can cause respiratory problems in mature, small-breed dogs. This study aimed to evaluate the placement of an intratracheal titanium alloy stent to prevent tracheal stenosis in canine tracheal anastomosis. MATERIALS AND METHODS: The self-expandable intratracheal stent was an alloy of nickel and titanium, at the same atomic ratio. Vital signs and respiratory patterns, C-reactive protein, radiography, computed tomography, and endoscopy results after intraluminal stenting were assessed for 3-5 months. RESULTS: No dogs showed evidence of intraluminal tracheal stenosis or tracheitis in the region of stent insertion on tracheoscopy and computed tomography after tracheal stent placement. After 1-2 weeks of tracheal stent placement, all dogs resolved coughing and dyspnea signs and resumed normal activities. CONCLUSION: The intratracheal stent showed no movement or deformation in the trachea, and had flexibility and an appropriate radial force. Therefore, titanium alloy tracheal stents are useful in stenotic operations for tracheal reconstruction.

Renal uptakes of 99mTc-MAG3, 99mTc-DTPA, and 99mTc-DMSA in rabbits with unilateral ureteral obstruction.

Renal function measurements using (99m)Tc-DTPA and (99m)Tc-MAG(3) dynamic scintigraphs were compared to those obtained using (99m)Tc-DMSA static scintigraphy. Eighteen experimental rabbits were randomly divided into (99m)Tc-DTPA-, (99m)Tc-MAG(3)-, and (99m) Tc-DMSA-injected groups. Experimental unilateral renal damage was induced by ligating a unilateral right ureter in 18 rabbits. Scintigraphic images were obtained at 2 and 5 h after intravenous injection of (99m)Tc-DMSA, or immediately after administration of (99m)Tc-DTPA or (99m)Tc-MAG(3). For the dynamic images using (99m)Tc-DTPA and (99m)Tc-MAG(3), rapid sequential images were obtained every 2 s for 30 images up to 1 min. The three groups presented different relative renal functions between the left normal and the right abnormal kidneys at 1, 2, 3, and 4 weeks post-ligation (p<0.05). However, the between-group comparisons showed no significant differences at any time. These results suggest that dynamic images of (99m)Tc-DTPA and (99m)Tc-MAG(3) can be used to measure the relative renal function in place of the static image of (99m)Tc-DMSA.

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.

Treatment of hydrocephalus with high-pressure valve ventriculoperitoneal shunt in a dog.

A 5-month-old male Maltese with right-sided circling, deafness, and blindness was presented. A diagnosis of communicating hydrocephalus was made. A ventriculoperitoneal shunt was implanted and the cerebrospinal fluid was drained by using an adjustable valve type (Medtronic Strata). The valve was set at 2.5 (135-155 mmH2O). This was done to prevent the possibility of an overdrainage-induced collapse of the brain parenchyma, which can occur rarely when canine hydrocephalus is treated by using a low-pressure valve. Computed tomography performed 6 weeks and 1 year after surgery revealed the ventricles had decreased in size. Thus, a high-pressure valve used during the treatment of hydrocephalus was able to maintain normal intracranial pressure.

Evaluation of Goose-beak Bone Particles for Dentoalveolar Reconstruction in Dogs.

BACKGROUND/AIM: Tooth extraction is a common procedure in dental clinics. Tooth extraction can destroy gingiva, alveolar bone, periodontal ligaments and cement. If dental sockets are left as extracted, it will result in loss of teeth, as well as voice and aesthetic problems. A natural hydroxyapatite (HA) bioceramic bone graft substitute developed from goose-beak bone particles (GBPs) was used for dentoalveolar reconstruction in a canine model. MATERIALS AND METHODS: Four adult (18-22 months old) male beagle dogs weighing 8.2-9.6 kg were included in the study. Eight alveolar extraction sockets in the four dogs were divided randomly into two groups and a split-mouth design was established; control group, socket filled with commercial synthetic HA; tested group, socket filled with granulated GBP. RESULTS: Micro-CT analysis and hematoxylin and eosin and Masson's trichrome staining of non-decalcified sections were undertaken. Examination revealed that dentoalveolar reconstruction was initiated from the periphery of the host bone, and newly formed bone was well integrated with the GBP. Bone apposition was observed at the edge of the host bone-GBP interface. CONCLUSION: A natural ceramic powder obtained from GBP is suitable for use in dentoalveolar reconstruction in dogs.

Evaluation of Renal Function in Obstructed Ureter Model Using 99mTc-DMSA.

BACKGROUND/AIM: Urinary obstruction is a condition of impaired urinary drainage, which may result in progressive renal deterioration. This study applied 99mTc-labeled dimercaptosuccinic acid (99mTc-DMSA) renal scintigraphy to a rabbit model of right ureter obstruction and evaluated its utility in studying obstructive renal diseases. MATERIALS AND METHODS: Complete unilateral ureter obstruction in rabbits was generated by complete ligation of the right ureter. Renal function was investigated during a 4-week post-obstruction period by obtaining planar images of 99mTc-DMSA activity following ear vein injection. Renal blood perfusion was evaluated by non-invasive scintigraphy in conjunction with parallel histological and hematological examinations. RESULTS: Renal perfusion was remarkably and rapidly reduced in the ureter-obstructed kidneys. During the experimental period, the size of left kidney appeared normal in the scintigraphic images, but the ureter-obstructed right kidney progressively became larger. Histopathological examination showed flattening and atrophy of tubules, enlargement of interstitial areas, accumulation of extracellular martices and infiltration of inflammatory cells in the obstreucted kidney. CONCLUSION: 99mTc-DMSA scintigraphy is a sensitive, non-invasive method to assess renal function in unilateral kidney diseases.

Osteogenic Evaluation of Hydroxyapatite Scaffold Loaded With Dexamethasone in Femoral Drill Holes.

BACKGROUND/AIM: Many cases of bone damage are due to trauma and metabolic diseases. This study aimed to evaluate bone regeneration into a porous hydroxyapatite (HA) scaffold using dexamethasone (DM)-loaded polymeric microspheres. MATERIALS AND METHODS: Four adult dogs were used to evaluate the in vivo performance of DM-loaded microspheres immobilized on the surfaces of porous HA scaffolds. Two 5-mm drill holes were created in both the left and right femurs of each dog. The experimental groups included a control group (drill holes filled with HA scaffold alone), a DM 20 group (holes filled with DM-loaded HA scaffold with 20 mg DM per scaffold), and a DM 100 group (hole filled with DM-loaded HA scaffold with 100 mg DM per scaffold). Resulting bone volume percentages and bone mineral densities were calculated by examing micro-computed tomographic (CT) images. RESULTS: The DM-loaded HA scaffold groups showed a gradual periosteal reaction two weeks after insertion of the HA scaffold into the femoral drill holes. Four weeks after HA scaffold insertion, the periosteal reaction in the femoral drill holes became denser. Eight weeks after insertion of DM-loaded HA scaffolds, clear images of the scaffold were observed in micro-CT images of the femoral drill hole. The DM 100 group had better bone healing tendencies (bone mineral density, bone mass, trabecular volume, bone surface, and trabecular thickness) than the DM 20 group. CONCLUSION: DM-loaded HA scaffolds are suitable platforms for distributing bioactive molecules during osteogenesis in femoral drill holes.

Osteogenic Evaluation of Goose-beak Bones According to Processing Temperature.

BACKGROUND/AIM: As an alternative material to autogenous bone, goose-beak bone particles (GBP) have been attracting great attention as a bone substitute due to their biological properties. This study was performed to assess bone generation using GBP in calvarial defects in a rat model. The study focus was the osteogenic potential of goose-beak bone at different processing temperatures. MATERIALS AND METHODS: There were three experimental groups: Control group (critical defect only), low-temperature (LT) group (filled with GBP heat-treated for 20 h at 400°C), and high-temperature (HT) group (filled with GBP heat-treated for 3 h at 1,200°C). RESULTS: The Ca/P atomic ratio of the goose-beak bone was 1.63, and the bones had a bony structure with open pores and interconnected rod-like struts. Micro-computed tomographic analysis revealed the quantity of new bone formation of the HT group was higher than that of the LT group. At 12 weeks after GBP insertion, new bone formation was significantly higher (p<0.05) in the HT group, and there were more new osteocytes in the lacuna in the HT group than in the LT group. Thus, GBP treated at a high temperature formed more new bone than that treated at a low temperature. CONCLUSION: It can be concluded that HT-treated GBP is a graft material that can be effective in promoting bone formation.

Reversing Effect of Insulin on Local Anesthetics-Induced Sciatic Nerve Block in Rats.

BACKGROUND: Local anesthetics are used in various purposes from topical and infiltration anesthesia to peripheral nerve or central neural blockade. Even though local anesthetics are relatively safe, they can have some toxic and adverse effects. Prolonged sensory and motor block is another example of an unwanted complication. The primary objective of this study was to determine whether insulin has a reversal effect on the peripheral (sciatic) nerve block with lidocaine or bupivacaine. METHODS: The surgically exposed sciatic nerves in rats were blocked with lidocaine or bupivacaine, and then 0.1 ml of normal saline or 0.1 ml normal saline containing 0.1 IU a short-acting form of insulin was administrated per body in each group. Before and after sciatic nerve block, as well as until recovery from the nerve block after normal saline or insulin treatment, nerve conduction studies such as monitoring loss and recovery of the waveforms and amplitudes were performed to evaluate the status of motor nerve conduction. RESULTS: Complete recovery time of nerve conduction status in lidocaine + normal saline group was 58 ± 16 min, whereas that in lidocaine + insulin group was 17 ± 3 min and the difference was statistically significant (p < 0.01). Complete recovery time of nerve conduction status in bupivacaine + normal saline group was 116 ± 16 min and that in bupivacaine + insulin group was 36 ± 4 min and the two groups were significantly different (p < 0.01). CONCLUSIONS: Insulin can reverse peripheral nerve block induced by lidocaine or bupivacaine.