Cells

The earliest effect of spaceflight is an alteration in vestibular function due to microgravity. Hypergravity exposure induced by centrifugation is also able to provoke motion sickness. The blood-brain barrier (BBB) is the crucial interface between the vascular system and the brain to ensure efficient neuronal activity. We developed experimental protocols of hypergravity on C57Bl/6JRJ mice to induce motion sickness and reveal its effects on the BBB. Mice were centrifuged at 2× for 24 h. Fluorescent dextrans with different sizes (40, 70 and 150 kDa) and fluorescent antisense oligonucleotides (AS) were injected into mice retro-orbitally. The presence of fluorescent molecules was revealed by epifluorescence and confocal microscopies in brain slices. Gene expression was evaluated by RT-qPCR from brain extracts. Only the 70 kDa dextran and AS were detected in the parenchyma of several brain regions, suggesting an alteration in the BBB. Moreover, Ctnnd1, Gja4 and Actn1 were upregulated, whereas Jup, Tjp2, Gja1, Actn2, Actn4, Cdh2 and Ocln genes were downregulated, specifically suggesting a dysregulation in the tight junctions of endothelial cells forming the BBB. Our results confirm the alteration in the BBB after a short period of hypergravity exposure.Développement d'une infrastructure française distribuée coordonné

Effects of centrifugation and whole-body vibrations on blood–brain barrier permeability in mice

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Validated Laser Doppler protocol for measurement of mouse bone blood perfusion - response to age or ovariectomy differs with genetic background

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Assessment of bone vascularization and its role in bone remodeling

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Functionalization of matrices by cyclically stretched osteoblasts through matrix targeting of VEGF.

International audienceVascular endothelial growth factor A (VEGF) plays a central role in load-induced bone gain. We previously showed that increasing cyclic stretch frequency from 0.05 to 5 Hz induce parallel increased in entrapment of VEGF (mVEGF) into osteoblast secreted extracellular matrix. We ask in this study if mVEGF could be protective against apoptotic signals and biologically active in vitro on endothelial cell migration as well as in vivo on angiogenesis. We established that mechanically-induced VEGF entrapment using stretched silicone membrane was saturable after 3 exposures at high frequency stretches (5Hz). We found that mVEGF stimulates microvascular cells migration and enhanced angiogenesis more importantly than VEGF 165 controls suggesting the absence of potent anti-angiogenic factors in our functionalized matrices. Indeed we found that the anti-angiogenic factors, tissue inhibitor of metalloproteinase (TIMP2) and pigment epithelium-derived factor (PEDF) were specifically downregulated for 5 Hz stretch and that the release of these potent factors was increased for low frequency of stretch (0.05 Hz). This study qualifies high frequency cyclic stretch as an interesting approach for surfaces activation of deformable biomaterials

Similar effect of co-administration of methotrexate and folic acid for the treatment of arthritis compared to separate administration

International audienceAbstract Objectives MTX is the recommended first-line treatment for RA associated with folic acid (FA) to reduce side effects related to MTX. Here, we proposed to test a co-administration of MTX with FA in the rat adjuvant-induced arthritis (AIA) on efficacy. Material and methods AIA was induced in female Lewis rats and treated with MTX in three groups. The first group of rats received only MTX (n = 13), whereas the second received MTX and FA on the same day (n = 14). The third group received FA one day after MTX (n = 14). Arthritic index (AI), ankle circumference (AC), ankle microcomputed tomography, and blood tests assessed arthritis severity and MTX tolerance. Results AI and AC were similar in MTX groups at various time points. Bone erosion and bone loss parameters were similar in all groups. MTX-PG1 was found at similar levels in various MTX groups and correlated negatively with arthritis severity. Finally, haematology and metabolic parameters were found at a similar level in MTX groups. Conclusion Co-administration of MTX with FA on the same day did not reduce efficacy compared with FA application one day after MTX. Thus, co-administration of MTX and FA could be more convenient and improve compliance in patients

Vascular imaging with contrast agent in hard and soft tissues using microcomputed-tomography

International audienceVascularization is essential for many tissues and is a main requisite for various tissue-engineering strategies. Different techniques are used for highlighting vasculature, in vivo and ex vivo, in 2-D or 3-D including histological staining, immunohistochemistry, radiography, angiography, microscopy, computed tomography (CT) or micro-CT, both stand-alone andsynchrotron system. Vascularization can be studied with or without a contrast agent. This paper presents the resultsobtained with the latest Skyscan micro-CT (Skyscan 1272, Bruker, Belgium) following barium sulphate injection replacingthe bloodstream in comparison with results obtained with a Skyscan In Vivo 1076. Different hard and soft tissues wereperfused with contrast agent and were harvested. Samples were analysed using both forms of micro-CT, and improvedresultswere shown using this new micro-CT. This study highlights the vasculature using micro-CT methods. The resultsobtained with the Skyscan 1272 are clearly defined compared to results obtained with Skyscan 1076. In particular, this instrument highlights the high number of small vessels, which were not seen before at lower resolution. This new micro-CTopens broader possibilities in detection and characterization of the 3-D vascular tree to assess vascular tissue engineeringstrategies

Parathyroid Hormone 1-84 Targets Bone Vascular Structure and Perfusion in Mice: Impacts of its Administration Regimen and of Ovariectomy.

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Hypergravity as a gravitational therapy mitigates the effects of knee osteoarthritis on the musculoskeletal system in a murine model

International audienceInsights into the effects of osteoarthritis (OA) and physical interventions on the musculoskeletal system are limited. Our goal was to analyze musculoskeletal changes in OA mice and test the efficacy of 8-week exposure to hypergravity, as a replacement of physical activity. 16-week-old male (C57BL/6J) mice allocated to sham control and OA groups not centrifuged (Ctrl 1g and OA 1g, respectively) or centrifuged at 2g acceleration (Ctrl 2g and OA 2g). OA 1g displayed decreased trabecular bone in the proximal tibia metaphysis and increased osteoclastic activity and local TNF alpha gene expression, all entirely prevented by 2g gravitational therapy. However, while cortical bone of tibia midshaft was preserved in OA 1g (vs. ctrl), it is thinner in OA 2g (vs. OA 1g). In the hind limb, OA at 1g increased fibers with lipid droplets by 48% in the tibialis anterior, a fact fully prevented by 2g. In Ctrl, 2g increased soleus, tibialis anterior and gastrocnemius masses. In the soleus of both Ctrl and OA, 2g induced larger fibers and a switch from type-II to type-I fiber. Catabolic (myostatin and its receptor activin RIIb and visfatine) and anabolic (FNDC5) genes dramatically increased in Ctrl 2g and OA 2g (p<0.01 vs 1g). Nevertheless, the overexpression of FNDC5 (and follistatine) was smaller in OA 2g than in Ctrl 2g. Thus, hypergravity in OA mice produced positive effects for trabecular bone and muscle typology, similar to resistance exercises, but negative effects for cortical bone