Left Hindlimb Research Articles

Vertical ground reaction forces, paw pressure distribution, and center of pressure during heelwork in working dogs competing in obedience.

Heelwork walking is a command that competitive obedience and working dogs are trained to perform. Unlike other canine sports, the research for competitive obedience sport is limited and no research regarding biomechanical gait adaptions during heelwork walking has been published. The aim of the study was to investigate the changes in vertical ground reaction forces, paw pressure distribution (PPD), and center of pressure (COP) of Belgian Malinois during heelwork walking. Ten healthy Belgian Malinois were included in the study. The dogs walked first without heeling (normal walk) and then while heeling on a pressure platform. The comparison between normal and heelwork walking was performed using mixed-effects models. Post-hoc analyses were performed using Sidak's alpha correction procedure. During heelwork walking, a significant decrease in the vertical impulse and stance phase duration (SPD) and a significant increase in the craniocaudal index and speed of COP was observed in the forelimbs compared to normal walking. At the hindlimbs, a significant increase in vertical impulse and SPD was observed during heelwork walking. Regarding PPD, a significant decrease of vertical impulse was observed at the cranial quadrants of the right forelimb and craniolateral quadrant of the left forelimb during heelwork. The area was significantly decreased at the craniolateral quadrant of the left forelimb and the time for the peak vertical force was prolonged significantly at the caudal quadrants of the right forelimb during heelwork walking. The vertical impulse was significantly increased in all quadrants of the hindlimbs except the craniolateral quadrant of the left hindlimb. The effect of these changes on the musculoskeletal system of working dogs should be investigated in further studies, using electromyography and kinematic analysis.

Progressive tremor and motor impairment in seizure-prone mutant tremor mice are associated with neurotransmitter dysfunction

BackgroundThe tremor mutant mice present motor impairments comprised of whole-body tremors, ataxia, decreased exploratory behavior, and audiogenic seizures. ObjectivesThis study aims to investigate the development of motor dysfunction in this mutant mouse and the relationships with cortical, striatal, and cerebellar levels of GABA, glutamate, glycine, dopamine (DA), serotonin (5-HT), noradrenaline (NOR), and its metabolites. The serum cytokines levels, myelin content, and the astrocytic expression of the glial fibrillary acidic protein (GFAP) investigated the possible influence of inflammation in motor dysfunction. ResultsRelative to wild-type (WT) mice, the tremor mice presented: increased tremors and bradykinesia associated with postural instability, decreased range of motion, and difficulty in initiating voluntary movements directly proportional to age; reduced step length for right and left hindlimbs; reduced cortical GABA, glutamate and, aspartate levels, the DOPAC/DA and ratio and increased the NOR levels; in the striatum, the levels of glycine and aspartate were reduced while the HVA levels, the HVA/DA and 5HIAA/5-HT ratios increased; in the cerebellum the glycine, NOR and 5-HIAA levels increased. ConclusionsWe suggest that the motor disturbances resulted mainly from the activation of the indirect striatal inhibitory pathway to the frontal cortex mediated by GABA, glutamate, and aspartate, reducing the dopaminergic activity at the prefrontal cortex, which was associated with the progressive tremor. The reduced striatal and increased cerebellar glycine levels could be partially responsible for the mutant tremor motor disturbances.

Suspected ischaemic myelopathy following lumbosacral epidural steroid injection in a dog

AbstractAn 11‐year‐old, female, spayed crossbreed with an 18‐month history of degenerative lumbosacral stenosis presented for routine epidural steroid injection 4 months after previous injection. Following epidural steroid injection, the dog developed severe left hindlimb paresis with reduced to absent sciatic reflexes, delayed conscious proprioception in the limb, absence of anal tone and lower motor neuron urinary incontinence. Magnetic resonance imaging was performed, which demonstrated findings consistent with an ischaemic myelopathy. The dog's left hindlimb paresis improved on cage rest; however, urinary incontinence remained. The dog was subsequently euthanased due to quality‐of‐life concerns. This is the first published report of suspected ischaemic myelopathy developing in a dog after epidural steroid injection.

Management of canine distemper, canine babesiosis, helminthiasis in a 6-month-old Nigerian indigenous breed of dogs bitch in Jos - Nigeria

A 6-month-old Nigerian indigenous breed of dog bitch was presented to the Small animal clinic of the University of Jos veterinary teaching hospital, Jos, Plateau State, Nigeria, with the complaint of paresis and involuntary movement of the left hindlimb and no vaccination history. On clinical examination, the vital parameters were temperature of 39.4 ⁰C, pulse rate of 80 beats per minute and respiratory rate of 60 cycles per minute. The clinical signs were congested ocular mucous membranes, bilateral mucoid oculo-nasal discharge, hardened nasal planum, inflamed submandibular lymph nodes (lymphadenopathy), paresis of the hind limbs, hardened footpads, myoclonus of the left hind limbs (distemper myoclonus), fleas on the ventral abdomen, and epilation. Diagnosis was made based on history, clinical signs, lymphopaenia, canine distemper inclusions bodies, and Babesia canis on the blood smear. The treatment was symptomatical and supportive. The patient partially recovered 7-days post-therapy as the hind limb myoclonus persisted.

Influence of Different Sevoflurane Concentrations on Postoperative Cognitive Function in Aged Rats.

Postoperative cognitive dysfunction may be associated with neuroinflammation, and sevoflurane suppresses surgery-induced inflammation. We hypothesized that low concentrations of sevoflurane would result in more impaired postoperative cognitive function compared to high concentrations. Aged male Sprague-Dawley rats (n = 21, 17-22 months) were randomly assigned to 1 of 3 groups: control (C), sevoflurane 2% (S2), and sevoflurane 4% (S4). Rats in the S2 and S4 groups underwent open femoral fracture and intramedullary fixation of the left hind limb under 2 hours of sevoflurane anesthesia. Neurological outcomes were evaluated using the Morris water maze (MWM) test, and histopathological outcomes were assessed 28 days after surgery. The S2 group showed prolonged swimming latency compared to S4 on day 7 (difference of means, 34.4; 95% confidence interval [CI], 2.57-66.3; P = .031) and compared to the C group on day 9 (difference of means, -33.4; 95% CI, -65.3 to -1.55; P = .037). The intact CA1 cells in the S2 group were significantly less than those in the C and S4 groups (H statistic, 10.87; P = .006 versus C; P = .033 versus S4). We found that low concentrations of sevoflurane prolonged the swimming latency of the MWM compared to high concentrations and reduced intact CA1 hippocampal neurons in aged rats. These results suggest that low-concentration sevoflurane anesthesia may be more detrimental than high concentration for spatial cognitive function and postoperative impairment of hippocampal CA1 cells in aged rats.

First description of interdigital hyperplasia associated with contagious ovine digital dermatitis in two sheep.

Interdigital hyperplasia (IH) is a fold of fibrous tissue protruding into the interdigital space that rarely occurs in sheep. Interdigital hyperplasia secondary infected with bovine digital dermatitis (BDD) treponemes has been reported in cattle in the course of the increasing spread of classical BDD lesions. In this report, we describe proliferative/ulcerative interdigital lesions associated with contagious ovine digital dermatitis (CODD) treponemes and clinically scored as (IH+CODD), occurring in both hind limbs of a ram and the left hindlimb of a ewe. Both cases exhibited epidermal hyperplasia, parakeratosis and focal-extensive areas of epidermal necrosis with numerous infiltrating neutrophils. Treponema PCR and fluorescence in situ hybridization (FISH) were positive for Treponema phylotype 1 (PT1). In addition, Dichelobacter (D.) nodosus and Porphyromonas (P.) levii were detected in the biopsy by PCR. In three slaughter sheep, without claw lesions, which were kept together with both affected sheep, Treponema spp. were detected neither with PCR nor FISH; the PCRs for D. nodosus and P. levii were also negative. Complete clinical healing occurred in the ewe within 6 weeks after three local applications of a chlortetracycline spray in 2 weeks intervals. This report is the first description of IH+CODD in sheep as demonstrated by a combination of histopathological and molecular analyses.

PER1 promotes functional recovery of mice with hindlimb ischemia by inducing anti-inflammatory macrophage polarization

Hindlimb ischemia (HLI) is an arterial occlusive disease that exposes the patients to the risk of limb gangrene and loss. Polarization of macrophages is related to HLI-induced inflammation. Period circadian regulator 1 (PER1) is a core component of the circadian clock. We first showed, based upon bioinformatics analysis of microarray data, that PER1 expression was reduced in monocytes from patients with critical limb ischemia. The proximal femoral artery in the left hindlimb of male mice was ligated and then the femoral artery and its collateral branches were removed to establish the HLI mouse model. After modeling, a single intramuscular injection of 1 × 109 pfu Ad-PER1 was performed at the adductor and gastrocnemius muscles. The gastrocnemius muscle tissues were collected at day 0, 3, 7, 14, 21 post-HLI. There was obvious pathological necrosis, accompanied with reduced expression of PER1 in the muscle tissues of HLI mice. Expression of CD68 and CD31 seemed to be corresponded to PER1 in gastrocnemius muscle, implying the potential of PER1 in regulating macrophage-related inflammation and angiogenesis. PER1 overexpression diminished myocyte damage, promoted blood flow restoration and improved behavioral scores of HLI mice. Immunostaining of CD31 and α-SMA revealed that PER1 upregulation reversed HLI-induced decreases in capillary and arteriole density. In vitro, RAW264.7 cells were cultured in hypoxia (1% O2) for 24 h. The percentage of pro-inflammatory CD86+ macrophages (M1 type) was decreased and that of anti-inflammatory CD206+ macrophages (M2 type) was increased when PER1 was overexpressed. Moreover, the expression levels of TNF-α, IL-6 and M1-type marker iNOS were decreased, and levels of IL-10 and M2-type marker Arg-1 were increased by PER1 in gastrocnemius muscle of HLI mice and hypoxia-treated RAW264.7 cells. PER1 might reduce M1 macrophage polarization and promote M2 macrophage polarization, and thus exert anti-inflammatory and pro-angiogenic actions. Our findings suggest that PER1 overexpression promotes functional recovery of mice with HLI through regulating macrophage polarization.

Correção Cirúrgica de Desvio Angular Metatársico em uma Potra Puro-sangue Utilizando Ostectomia em Cunha: um relato de caso

Abstract This study describes a corrective procedure for a metatarsal angular malformation using wedge ostectomy in a 41-day-old Thoroughbred filly. A 41.6 °angular malformation of the metatarsus was corrected with wedge ostectomy of the left hindlimb in association with a type II external fixator and methyl methacrylate resin. The animal was subjected to the surgical procedure under general anesthesia. The filly was placed in dorsal recumbency with the left hind limb free for manipulation. A bone saw was used for the wedge ostectomy, while the bars for external fixation were placed using a drill. A Kirschner pin and acrylic resin were then applied. Radiographic images obtained immediately after surgery confirmed a total malformation reduction of 32.6 (from 41.6° to 9°). With medication and a Robert Jones bandage, intensive postoperative care was instituted to ensure that the animal adapted properly to the linear external fixator without overloading the pins and connection bars. No postoperative complications were observed. On the day after surgery, the filly was standing and walking with no signs of pain. After 180 days, total osseous calcification was achieved, and the implants were removed during the second surgery. The filly demonstrated adequate locomotion, performed all the movements, and ran without any difficulty in the paddock. The remaining discrete angular deviations were partially corrected using hoof trimming.

The development of a mouse model to investigate the formation of heterotopic ossification.

Muscle injury and concomitant bone injury are important drivers to induce heterotopic ossification (HO). However, the related roles of muscle and concomitant bone injury in HO formation are still unclear. This study aims to develop a mouse model through the combination of hindlimb amputation (Am) and cardiotoxin (CTX) injection to investigate the mechanism of HO formation. The mice were randomly divided into Am group (Am of right hindlimb, n = 12), CTX group (CTX injection in the calf muscle of left hindlimb, n = 12) and Am + CTX group (the combination of Am of right hindlimb and CTX injection of left hindlimb, n = 18). MicroCT was used to evaluate the incidence of HO. Histology was used to investigate the progression of HO. The MicroCT showed that only Am or CTX injection failed to induce HO while the combination of Am and CTX injection successfully induced HO. The incidence of HO was significant in Am + CTX group on day 7 (0% vs 0% vs 83.3%, p = 0.001) and day 14 (0% vs 0% vs 83.3%, p = 0.048). HO was located on the left hindlimb where CTX was injected. Moreover, the bone volume and bone density on day 14 were higher than those on day 7 in Am + CTX group. Histology revealed the evidence of calcification and expression of osteogenic markers in calcification sites in Am + CTX group. In summary, the combination of Am and CTX injection could successfully induce dystrophic calcification/HO, which occurs in the location of muscle injury.

Surgical management of irreparable injuries of left hind limb and tail in a black footed gray Langur (Semnopithecus hypoleucos)

Surgical management of irreparable injuries of left hind limb and tail in a black footed gray Langur (Semnopithecus hypoleucos)

Disseminated aspergillosis in a German shepherd mixed breed dog with unusual initial localization to the iliac wing.

A female, 1.5 years old, mixed‑breed dog, was presented for left hind limb lameness. Radiographs revealed an irregular periosteal proliferation on the left iliac wing. The clinical condition worsened with generalised enlargement of the lymph nodes, azotaemia, and pyelonephritis. The magnetic resonance imaging of the pelvis and a surgical biopsy diagnosed a mycotic myositis and osteomyelitis of the iliac wing and gluteal muscles. Aspergillus terreus was isolated from culture of urine and lymph nodes aspirates. The antifungal susceptibility test showed moderate sensitivity to Itraconazole. After one month of therapy with itraconazole, the dog presented discospondylitis of L1‑L2 and partial ureteral obstruction due to mycotic bezoar that was resolved with medical treatment and itraconazole dose elevation. After twelve months, itraconazole was suspended; a severe osteomyelitis of the left femur developed, and the dog was euthanised. The necropsy confirmed the presence of mycotic osteomyelitis of the iliac wing and femur, discospondylitis, lymphadenitis and severe granulomatous pyelonephritis. Systemic aspergillosis has rarely been reported in the literature, especially in Italy. The pelvic bone involvement is rare both in dogs and humans. Although itraconazole treatment allowed remission of the clinical signs for one year, it was not able to cure the dog.

The non-intuitive, in-vivo behavior of aponeuroses in a unipennate muscle

Experimental observations and theoretical models suggest that the loading of muscular aponeuroses is complex, causing strain patterns that are not reconcilable with the frequently assumed mechanical “in series” arrangement of aponeuroses with muscles and tendons. The purpose of this work was to measure the in-vivo longitudinal strains of the distal and proximal aponeuroses and force of the unipennate Medial Gastrocnemius (MG) muscle during locomotor activities. Sonomicrometry crystals and a force buckle transducer were implanted to measure aponeurosis strains and MG forces in the left hindlimb of four healthy female sheep while walking at different speeds and inclination angles on a motorized treadmill. The resulting aponeurosis strains versus the corresponding muscle forces resulted in a complex interaction that is not reconcilable with a mechanical “in series” arrangement of aponeuroses with either the free tendon or muscle, as has frequently been assumed when trying to determine the storage and release of mechanical energy in muscles or the stiffness and elastic modulus of in-vivo aponeurosis tissues. We conclude that the interaction of muscle tissue with aponeuroses in the sheep MG allows for elongation of the aponeuroses at low forces in the passive muscle, while elongation in the active muscle is greatly reduced possibly due to the complex shear forces and pressures produced when the muscle is activated. It is likely that the observed aponeurosis mechanics are similar in other unipennate skeletal muscles, but the current study was limited to a single muscle and therefore does not allow for such extrapolation at this time.

Acupotomy relieves pain and improves motor function by regulating autophagy and apoptosis of cartilage in rabbits with knee osteoarthritis apoptosis

To observe the effect of acupotomy on the expression of Beclin-1, Bcl-2 and Caspase-3 in the cartilage tissue in rabbits with knee osteoarthritis (KOA), so as to explore its mechanism underling improvement of KOA. Twenty-four healthy male New Zealand rabbits were randomly and equally divided into blank control, model and acupotomy groups, with 8 rabbits in each group. By using the modified Videman's methods, the KOA model was established by left hind limb immobilization with a plaster cast for 6 weeks. The severity of KOA (knee pain, swelling and motor function) was assessed using Lequesne score, and the rabbits with a score below 4 were excluded. The acupotomy was applied to "Hedingci" (the attachment of the quadriceps tendon to the patella at the upper edge), "Binneixia" (the medial patellar supporting band attachment of medial inferior patellar margin), "Binwaixia" (the lateral patellar supporting band attachment of the lower lateral patellar margin), "Chengfeijian" (the lateral collateral ligament of the knee passes over the lateral joint space), "Weiyangci" (the medial margin of biceps femoris at the lateral end of popliteus), "Yinlingci" (the medial tibial attachment of anserinus tendon) on the left hind limb once a week for 4 weeks. One week after the last intervention, the left knee joint dysfunction severity(pain, maximum walking distance, and some activities of daily living) was evaluated by using modified Lequesne score. Histopathological changes of the cartilage were observed under light microscope after H.E. staining. The apoptosis of chondrocytes was observed after terminal deoxynucleotidyl transferase-mediated fluorescein-dUTP nick-end labeling (TUNEL) staining. The autophagolysosomes of chondrocytes were observed using transmission electron microscopy. The expression levels of Beclin-1, Bcl-2 and Caspase-3 (related factors of autophagy and apoptosis) were detected using Real-time PCR and Western blot separately. In comparison with the blank control group, the Lequesne score, apoptosis rate, expression levels of Caspase-3 mRNA and protein were significantly increased (P<0.001), and the number of autophagolysosomes, expression levels of Beclin-1 and Bcl-2 mRNAs and proteins considerably decreased (P<0.001) in the model group. Relevant to the model group, the acupotomy group had an obvious decrease in Lequesne score, rate of apoptosis, and expression levels of Caspase-3 mRNA and protein (P<0.001) and an apparent increase in the number of autophagolysosomes and expression levels of Beclin-1 and Bcl-2 mRNAs and proteins (P<0.001). Findings of H.E. staining showed severe damaged cartilage surface, with a large number of exfoliation defects, few chondrocytes on the surface and disordered arrangement of transitional cells in the model group, which was relatively milder in the acupotomy group. Acupotomy can mitigate knee-joint pain and improve functional activity in KOA rabbits, which may be associated with its functions in promoting autophagy and suppressing apoptosis by up-regulating expressions of Beclin-1 and Bcl-2 mRNAs and proteins and down-regulation of Caspase-3 mRNA and protein.

SGLT2 inhibitor empagliflozin promotes revascularization in diabetic mouse hindlimb ischemia by inhibiting ferroptosis.

Gliflozins are known as SGLT2 inhibitors, which are used to treat diabetic patients by inhibiting glucose reabsorption in kidney proximal tubules. Recent studies show that gliflozins may exert other effects independent of SGLT2 pathways. In this study we investigated their effects on skeletal muscle cell viability and paracrine function, which were crucial for promoting revascularization in diabetic hindlimb ischemia (HLI). We showed that treatment with empagliflozin (0.1-40 μM) dose-dependently increased high glucose (25 mM)-impaired viability of skeletal muscle C2C12 cells. Canagliflozin, dapagliflozin, ertugliflozin, ipragliflozin and tofogliflozin exerted similar protective effects on skeletal muscle cells cultured under the hyperglycemic condition. Transcriptomic analysis revealed an enrichment of pathways related to ferroptosis in empagliflozin-treated C2C12 cells. We further demonstrated that empagliflozin and other gliflozins (10 μM) restored GPX4 expression in high glucose-treated C2C12 cells, thereby suppressing ferroptosis and promoting cell viability. Empagliflozin (10 μM) also markedly enhanced the proliferation and migration of blood vessel-forming cells by promoting paracrine function of skeletal muscle C2C12 cells. In diabetic HLI mice, injection of empagliflozin into the gastrocnemius muscle of the left hindlimb (10 mg/kg, every 3 days for 21 days) significantly enhanced revascularization and blood perfusion recovery. Collectively, these results reveal a novel effect of empagliflozin, a clinical hypoglycemic gliflozin drug, in inhibiting ferroptosis and enhancing skeletal muscle cell survival and paracrine function under hyperglycemic condition via restoring the expression of GPX4. This study highlights the potential of intramuscular injection of empagliflozin for treating diabetic HLI.

Investigation of Thresholds for Asymmetry Indices to Represent the Visual Assessment of Single Limb Lameness by Expert Veterinarians on Horses Trotting in a Straight Line.

Defining whether a gait asymmetry should be considered as lameness is challenging. Gait analysis systems now provide relatively accurate objective data, but their interpretation remains complex. Thresholds for discriminating between horses that are visually assessed as being lame or sound, as well as thresholds for locating the lame limb with precise sensitivity and specificity are essential for accurate interpretation of asymmetry measures. The goal of this study was to establish the thresholds of asymmetry indices having the best sensitivity and specificity to represent the visual single-limb lameness assessment made by expert veterinarians as part of their routine practice. Horses included in this study were evaluated for locomotor disorders at a clinic and equipped with the EQUISYM® system using inertial measurement unit (IMU) sensors. Visual evaluation by expert clinicians allocated horses into five groups: 49 sound, 62 left forelimb lame, 67 right forelimb lame, 23 left hindlimb lame, and 23 right hindlimb lame horses. 1/10 grade lame horses were excluded. Sensors placed on the head (_H), the withers (_W), and the pelvis (_P) provided vertical displacement. Relative difference of minimal (AI-min) and maximal (AI-max) altitudes, and of upward (AI-up) and downward (AI-down) amplitudes between right and left stance phases were calculated. Receiver operating characteristic (ROC) curves discriminating the sound horses from each lame limb group revealed the threshold of asymmetry indice associated with the best sensitivity and specificity. AI-up_W had the best ability to discriminate forelimb lame horses from sound horses with thresholds (left: -7%; right: +10%) whose sensitivity was greater than 84% and specificity greater than 88%. AI-up_P and AI-max_P discriminated hindlimb lame horses from sound horses with thresholds (left: -7%; right: +18% and left: -10%; right: +6%) whose sensitivity was greater than 78%, and specificity greater than 82%. Identified thresholds will enable the interpretation of quantitative data from lameness quantification systems. This study is mainly limited by the number of included horses and deserves further investigation with additional data, and similar studies on circles are warranted.

Effect of moxibustion on AMPK/ULK1 signaling pathway in synovium tissue of toes in rats with rheumatoid arthritis

To observe the effect of moxibustion on AMP-activated protein kinase (AMPK)/UNC-51-like kinase 1 (ULK1) signaling pathway in the synovial tissue of toes in rheumatoid arthritis rats, so as to explore the mechanism of mo-xibustion in the treatment of rheumatoid arthritis (RA). A total of 45 SD rats were randomly divided into blank, model， moxibustion, methotrexate and rapamycin groups, with 9 rats in each group. RA rat model was established by injection of Freund's complete adjuvant. Moxibustion was applied to "Zusanli" (ST36) and "Guanyuan" (CV4) for 20 min, once a day for 3 weeks. Methotrexate group was given methotrexate (0.35 mg/kg) by gavage, twice a week for 3 weeks. Rapamycin group was intraperitoneally injected with rapamycin (1 mg/kg)，once every other day for 3 weeks. The toe volume of the left hind limb of rats was measured by the toe volume measuring instrument. The content of AMP in toe synovium was detected by ELISA. The expression of AMPK and VPS34 protein in toe synovium was detected by Western blot.The expression of ULK1 and Atg13 mRNA in toe synovium was detected by RT-PCR. Compared with the blank group, the volume of toe in the model group was increased (P<0.01)，while the content of AMP, the expression of AMPK and VPS34 proteins, the expression of ULK1 and Atg13 mRNAs were significantly decreased(P<0.01).Compared with the model group, the volume of toe in the moxibustion，methotre-xate and rapamycin groups was decreased (P<0.05); the content of AMP, the expression of AMPK and VPS34 proteins, the expression of ULK1 and Atg13 mRNAs were significantly increased(P<0.05) in the moxibustion group; the content of AMP, the expression of VPS34 protein, the expression of Atg13 mRNA were significantly increased(P<0.05) in the methotrexate group; the expression of AMPK and VPS34 proteins, the expression of ULK1 and Atg13 mRNAs were significantly increased (P<0.05, P<0.01) in the rapamycin group. Compared with the moxibustion group, the expression of AMPK protein in the methotrexate group and the content of AMP in the rapamycin group were significantly decreased (P<0.05). Moxibustion can improve joint swelling in RA rats, and the mechanism may be related to promoting the activity of AMPK/ULK1 signaling pathway.

Changes in microvascular perfusion of heart and skeletal muscle in sheep around the time of birth.

What is the central question of this study? How does the microvascular perfusion of striated muscle change during the dynamic developmental period between the late gestation fetus and early neonate? What is the main finding and its importance? In both myocardium and skeletal muscle, perfusion of striated muscle is significantly reduced in the neonate compared to the late term fetus, but flow reserve is unchanged. The results suggest striated muscle capillary networks grow more slowly relative to the myofibres they nourish during the perinatal period. Microvascular perfusion of striated muscle is an important determinant of health throughout life. Birth is a transition with profound effects on the growth and function of striated muscle, but the regulation of microvascular perfusion around this transition is poorly understood. We used contrast-enhanced ultrasound perfusion imaging (CEUS) to study the perfusion of left ventricular myocardium and hindlimb biceps femoris, which are populations of muscle with different degrees of change in pre- to postnatal workloads and different capacities for postnatal proliferative growth. We studied separate groups of lambs in late gestation (135days' gestational age; 92% of term) and shortly after birth (5days' postnatal age). We used CEUS to quantify baseline perfusion, perfusion during hyperaemia induced by adenosine infusion (myocardium) or electrically stimulated unloaded exercise (skeletal muscle), flow reserve and oxygen delivery. We found heart-to-body weight ratio was greater in neonates than fetuses. Microvascular volume and overall perfusion were lower in neonates than fetuses in both muscle groups at baseline and with hyperaemia. Flux rate differed with muscle group, with myocardial flux being faster in neonates than fetuses, but skeletal muscle flux being slower. Oxygen delivery to skeletal muscle at baseline was lower in neonates than fetuses, but was not significantly different in myocardium. Flow reserve was not different between ages. Given the significant somatic growth, and the transition from hyperplastic to hypertrophic myocyte growth occurring in the perinatal period, we postulate that the primary driver of lower neonatal striated muscle perfusion is faster growth of myofibres than their associated capillary networks.

Anti-inflammatory activity of methanol and ethyl acetate fractions of Sesbania grandiflora roots in rats

The anti-inflammatory potential of methanol and ethyl acetate fractions of Sesbania grandiflora Linn., roots were evaluated by carrageenan induced rat paw oedema method and cotton pellet induced granuloma in rats. Female Wistar rats were treated orally with methanol (MFSGR) and ethyl acetate (EAFSGR) fractions of Sesbania grandiflora roots (100 and 200 mg/kg) and Diclofenac sodium (15 mg/kg). One-hour post treatment, Carrageenan (0.1 ml of 1 % w/v, s.c.) was administered in the sub plantar region of the left hind limb of rat. Thereafter, paw volume was measured at 0, 30 min, 1, 2, 3 and 4 h. Percentage inhibition (PI) of oedema was calculated. In cotton pellet-induced granuloma model, male Wistar rats were treated with Diclofenac sodium (10 mg/kg, p.o.) and MFSGR and EAFSGR (100 and 200 mg/kg, p.o.) respectively. Thirty-minutes after respective treatment, an autoclaved cotton pellet of 20±1 mg was aseptically implanted subcutaneously. Fraction and standard diclofenac were administered once daily for the next 7 days. On 8th day, excised cotton granuloma was dried and weighed, body weight and organ index were calculated. MFSGR and EAFSGR (100 and 200 mg/kg) exhibited a significant inhibition in paw volume against carrageenan-induced paw oedema. In cotton pellet induced granuloma model, MFSGR and EAFSGR exhibited significant inhibition of cotton dry and wet weight. The present study suggests that the methanol and ethyl acetate fractions of Sesbania grandiflora roots exhibit anti-inflammatory activity. The observed effect could be attributed to the presence of vital phytoconstituents.

Mechanism of nerve growth factor promotes angiogenesis and skeletal muscle fiber remodeling in a mouse hindlimb ischemic model

Objective: To explore the mechanism of nerve growth factor (NGF) in the skeletal muscle fiber remodeling in ischemic limbs during therapeutic angiogenesis. Methods: Eighteen female mice with SPF grade, 6 weeks old and 25-30 g weighed were randomly allocated to sham-operated group (n=6), blank control group (n=6) and NGF gene transfection group (n=6). The left hindlimb ischemia models were established by ligating the femoral artery in blank control group and NGF gene transfection group. Seven days after the operation, mice in the three groups were separately injected with normal saline, empty plasmids, and NGF plasmids. Gastrocnemius of left hindlimbs was harvested after the blood perfusion assessment of the ischemic limb on the 21st postoperative day. The gastrocnemius muscle specimens were stained with HE, CD31 and proliferating cell nuclear antigen (PCNA) immunohistochemistry staining, the mRNA expressions of myosin heavy chain-Ⅰ(MHC-Ⅰ), MHC-Ⅱa and MHC-Ⅱb were measured by real-time PCR, and the protein level of NGF and peroxisome proliferator-activated receptors-β/δ (PPAR β/δ) were detected by Western blot. The expression of cytochrome C oxidase (COX), isocitrate dehydrogenase (IDH) and adenosine triphosphate (ATP) were examined by enzyme-linked immunosorbent assay (ELISA). Results: On the 21st day after operation, the blood perfusion of the ischemic limb in NGF gene transfection group was (195.70±9.99)PU, which was lower than that in sham-operated group (312.15±17.32)PU (P=0.001), while it was higher than that in blank control group (82.11±8.55)PU (P=0.001). The degree of muscle atrophy in the NGF gene transfection group was lower than that in the blank control group. The capillary density of NGF gene transfection group (0.34±0.05) was higher than that of sham-operated group (0.11±0.03) and blank control group (0.27±0.04) (P<0.05). The endothelial cell proliferation index in NGF gene transfection group (0.39±0.19) was significantly higher than that in sham-operated group (0.18±0.01) and blank control group (0.25±0.14) (P<0.05). The expression of NGF, PPAR β/δ, COX, IDH, ATP, and MHC-Ⅰ mRNA in NGF gene transfection group were significantly higher than those in sham-operated group and blank control group (P<0.05). Conclusions: NGF gene transfection can promote angiogenesis in the ischemic limbs of mice, increase the blood perfusion, and thus induce the remodeling of skeletal muscle fibers to type Ⅰ. This process may be related to NGF-induced PPAR β/δ expression and promote the cellular aerobic metabolism in skeletal muscle.

Assessment of Gait Following Locking Plate Fixation of a Tibial Segmental Defect and Cast Immobilization in Goats

The purpose of this study was to analyze the effects of locking plate fixation used for bridging of tibial segmental ostectomy and of cast immobilization on gait biomechanics in goats. We hypothesized that stable fixation of a segmental bone defect, using a locking plate construct, would result in minimal changes in biomechanical variables of gait in goats, but full-limb immobilization would result in lasting alterations in the immobilized limb’s gait kinetics. A pressure-sensing walkway was used to measure biomechanical characteristics for stride, gait, and walking vertical force. Thirteen, non-lame adult Boer-cross goats were trained to walk over a pressure-sensing walkway prior to instrumentation. Segmental ostectomy was performed on the right hind tibia of each goat and the defect was stabilized using bridging plate fixation with a locking compression plate. Per the protocol of an ongoing orthopedic study, the same goats underwent right hindlimb cast immobilization between one and four months postoperatively. Data was collected preoperatively and then over twelve months postoperatively in goats with unrestricted mobility. Statistical analysis revealed no significant alterations in hindlimb kinematics or maximum force when comparing the period after surgery with that after cast immobilization; significant decreases in forelimb stride length and velocity were noted postoperatively but normalized prior to cast placement, suggesting the overall functional stability of fixation. Cast immobilization had a profound and sustained effect on gait with significant alterations in both forelimb kinetics and hindlimb kinetics and kinematics for the remainder of the trial period; increased hindlimb asymmetry characterized by greater weight distribution and impulse to the left hindlimb was observed, suggesting the potential for long-term and/or permanent detrimental effects of prolonged limb immobilization.