Use of FK506 and bone marrow mesenchymal stem cells for rat hind limb allografts

Dark Agouti rat donor hind limbs were orthotopically transplanted into Lewis rat recipients to verify the effects of bone marrow mesenchymal stem cells on neural regeneration and functional recovery of allotransplanted limbs in the microenvironment of immunotolerance, bone marrow mesenchymal stem cells were intramuscularly （gluteus maximus） injected with FK506 （tacrolimus） daily, and were transplanted to the injured nerves. Results indicated that the allograft group not receiving therapy showed severe rejection, with transplanted limbs detaching at 10 days after transplantation with complete necrosis. The number of myelinated axons and Schwann cells in the FK506 and FK506 ＋ bone marrow mesenchymal stem cells groups were significantly increased. We observed a lesser degree of gastrocnemius muscle degeneration, and increased polymorphic fibers along with other pathological changes in the FK506 ＋ bone marrow mesenchymal stem cells group. The FK506 ＋ bone marrow mesenchymal stem cells group showed significantly better recovery than the autograft and FK506 groups. The results demonstrated that FK506 improved the immune microenvironment. FK506 combined with bone marrow mesenchymal stem cells significantly promoted sciatic nerve regeneration, and improved sensory recovery and motor function in hind limb allotransplant.

1,25-Dihydroxyvitamin D_(3) effects on the regulation of the insulin receptor gene in the hind limb muscle and heart of streptozotocin-induced diabetic rats

In the present study, we examine the effects of the treatment with 1,25-dihydroxyvitamin D3 [150 IU/Kg (3.75 μg/Kg) once a day, for 15 days] to non-diabetic and streptozotocin-induced diabetic rats. The results indicate that treatment with 1,25-dihydroxyvitamin D3 had minor effects in non-diabetic rats. The same treatment in streptozotocin-induced diabetic rats, although it did not correct the hyperglycemia and hypoinsulinemia induced by the diabetes, caused other actions that could mean beneficial effects on the amelioration of diabetes e.g., it avoided body weight loss, increased calcium and phosphorus plasma levels, and corrected the over-expression of the insulin receptor mRNA species of 9.5 and 7.5 Kb present in the hind limb muscle and heart of these animals. These genomic 1,25-dihydroxyvitamin D3 effects could involve transcriptional mechanisms of repression mediated by vitamin D response elements in the rat insulin receptor gene promoter. Using computer analysis of this promoter, we propose the -249/-235 bp VDRE (5’GGGTGACCCGGGGTT3’) with a pyrimidine (T) in the (+7) position of the3’half-site as the best candidate for negative control by 1,25-dihydroxy-vitamin D3. In addition, posttranscriptional mechanisms of regulation could also be implicated. Thus, computer inspection of the5’untranslated region of the rat insulin receptor pre-mRNA indicated the presence of a virtual internal ribosome entry segment whereas the computer inspection of the3’untranslated region localized various destabilizing sequences, including various AU-rich elements. We propose that through these virtual cis-regulatory sequences, 1,25-dihydroxyvitamin D3 could control the translation and stability of insulin receptor mRNA species in the hind limb muscle and heart of diabetic rats.

Bionic Vibration Isolator Inspired by Goat Hind Limb

The goat’s hind limbs play an important role in dampening vibrations caused by ground impact during movement.Inspired by the unique structure of their hind limbs,a novel bionic limb vibration isolator has been developed to suppress low-frequency vibrations.It consists of the base,the carrying platform,four bionic legs and so on.The bionic legs are made up of rods of varying lengths and springs in different directions to imitate the various shapes of bones such as the femur and patella of the hind limbs of goats and developed muscles such as the biceps and quadriceps.The bionic device was found to have excellent nonlinear stiffness through statics analysis,and could be flexibly adjusted to the work range and load capacity.The bionic vibration isolator offers lower natural frequencies(2.3 Hz),better vibration isolation effect and a wider vibration isolation band than conventional linear vibration isolator.The bionic device can effectively suppress vibrations above 3.2 Hz and reduce the amplitude of random vibrations to more than 90%.In addition,compared to similar bionic vibration isolation devices,the bionic isolator achieves excellent load-bearing capacity in a smaller size,which facilitates its application in practical production.

Angiogenesis effect of Astragalus polysaccharide combined with endothelial progenitor cells therapy in diabetic male rat following experimental hind limb ischemia

Background Diabetes mellitus （DM） is a common disease accompanied with a high incidence of hind limb ischemia （HLI）.In recent years,numerous studies demonstrated that endothelial progenitor cells （EPCs） are involved in angiogenesis and maintenance of vascular integrity following HLI.On the other side,it has been proved that Astragalus polysaccharide （APS） could promote angiogenesis.In the present study,we aimed to evaluate the effect of APS and EPCs on enhancing angiogenesis after experimental HLI caused by femoral artery ligation in rats with streptozotocin （STZ）-induced diabetes.Methods Rats （n=110） were randomly assigned to the following groups：sham group,ischemia group,APS group,EPCs group and APS＋EPCs group.APS,EPCs or an equal volume of vehicle was administered intramuscularly after HLI induction,and 6 rats were assessed by angiography at 28 days after induction of HLI,6 rats were sacrificed at the same time point to take histological studies,biochemical tests were also performed at that point in the rest rats.Results APS or EPCs treatment induced an increase,respectively,in the protein expression of vascular endothelial growth factor （VEGF） （36.61%,61.59%）,VEGF receptor-1 （VEGFR-1） （35.50%,57.33%）,VEGFR-2 （31.75%,41.89%）,Angiopoietin-1 （Ang-1） （37.57%,64.66%） and Tie-2 （42.55%,76.94%） （P 〈0.05）,after HLI injury.And combined therapy of APS and EPCs enhanced the effort of angiogenesis after HLI induction in diabetic rats,through elevating protein expression of VEGF （99.67%）,VEGFR-1 （105.33%）,VEGFR2 （72.05%）,Ang-1 （114.30%） and Tie-2 （111.87%） （P〈0.05）.Similarly,mRNA expression of VEGF,VEGFR-1,VEGFR2,Ang-1,Tie-2 also show similar trends as well as protein expression （P〈0.05）.Conclusion APS or EPCs could enhance angiogenesis,and the combined treatment leads to better effort,at least,partially via VEGFNEGFR and Ang-1/Tie-2 signaling pathway.

Morphological determinants of jumping performance in the Iberian green frog

Predation is one of the main selective forces in nature, frequently selecting potential prey for developing escape strategies. Escape ability is typically influenced by several morphological parameters, such as morphology of the locomotor appendices, muscular capacity, body mass, or fluctuating asymmetry, and may differ between sexes and age classes. In this study, we tested the relationship among these variables and jumping performance in 712 Iberian green frogs Pelophylax perezi from an urban population. The results suggest that the main determinant of jumping capacity was body size (explaining 48% of variance). Larger frogs jumped farther, but jumping performance reached an asymptote for the largest frogs. Once controlled by structural body size, the heaviest frogs jumped shorter distances, suggesting a trade-off between fat storage and jumping performance. Relative hind limb length also determined a small but significant percentage of variance (2.4%) in jumping performance-that is, the longer the hind limbs, the greater the jumping capacity. Juveniles had relatively shorter and less muscular hind limbs than adults (for a given body size), and their jumping performance was poorer. In our study population, the hind limbs of the frogs were very symmetrical, and we found no effect of fluctuating asymmetry on jumping performance. Therefore, our study provides evidence that jumping performance in frogs is not only affected by body size, but also by body mass and hind limb length, and differ between age classes.