Neuroprotection and immunomodulation following intraspinal axotomy of motoneurons by treatment with adult mesenchymal stem cells

Abstract

BackgroundTreatment of spinal cord injury is dependent on neuronal survival, appropriate synaptic circuit preservation, and inflammatory environment management. In this sense, mesenchymal stem cell (MSC) therapy is a promising tool that can reduce glial reaction and provide trophic factors to lesioned neurons.MethodsLewis adult female rats were submitted to a unilateral ventral funiculus cut at the spinal levels L4, L5, and L6. The animals were divided into the following groups: IA (intramedullary axotomy), IA + DMEM (Dulbecco’s modified Eagle’s medium), IA + FS (fibrin sealant), IA + MSC (106 cells), and IA + FS + MSC (106 cells). Seven days after injury, qPCR (n = 5) was performed to assess gene expression of VEGF, BDNF, iNOS2, arginase-1, TNF-α, IL-1β, IL-6, IL-10, IL-4, IL-13, and TGF-β. The cellular infiltrate at the lesion site was analyzed by hematoxylin-eosin (HE) staining and immunohistochemistry (IH) for Iba1 (microglia and macrophage marker) and arginase-1. Fourteen days after injury, spinal alpha motor neurons (MNs), evidenced by Nissl staining (n = 5), were counted. For the analysis of astrogliosis in spinal lamina IX and synaptic detachment around lesioned motor neurons (GAP-43-positive cells), anti-GFAP and anti-synaptophysin immunohistochemistry (n = 5) was performed, respectively. Twenty-eight days after IA, the gait of the animals was evaluated by the walking track test (CatWalk; n = 7).ResultsThe site of injury displayed strong monocyte infiltration, containing arginase-1-expressing macrophages. The FS-treated group showed upregulation of iNOS2, arginase-1, proinflammatory cytokine (TNF-α and IL-1β), and antiinflammatory cytokine (IL-10, IL-4, and IL-13) expression. Thus, FS enhanced early macrophage recruitment and proinflammatory cytokine expression, which accelerated inflammation. Rats treated with MSCs displayed high BDNF-positive immunolabeling, suggesting local delivery of this neurotrophin to lesioned motoneurons. This BDNF expression may have contributed to the increased neuronal survival and synapse preservation and decreased astrogliosis observed 14 days after injury. At 28 days after lesion, gait recovery was significantly improved in MSC-treated animals compared to that in the other groups.ConclusionsOverall, the present data demonstrate that MSC therapy is neuroprotective and, when associated with a FS, shifts the immune response to a proinflammatory profile.Electronic supplementary materialThe online version of this article (10.1186/s12974-018-1268-4) contains supplementary material, which is available to authorized users.

Improvement of bone regeneration using fibrin biopolymer combined with differentiated stem cells

“…The BPF used in this study is composed of a mixture of a serine protease with thrombin-like enzyme activity, purified from Crotalus durissus terrificus snake venom and buffaloes cryoprecipitate as a source of fibrinogen 53, 30 . Previous studies has shown no cytotoxicity becoming an excellent scaffold for MSC 16, 34, 54, 55 .…”

“…Spejo et al 55 have demonstrated that MSC therapy is neuroprotective and when associated with a BPF shifts the immune response to a proinflammatory profile. According to them, thet was possible because BPF kept EGFP-MSC at the glial scar region in the ventral funiculus after 28 days.…”

Alternatively Polarized Macrophages Regulate the Growth and Differentiation of Ependymal Stem Cells through the SIRT2 Pathway

“…The inhibitory microenvironment formed following SCI is considered to play an important role in this process. Secondary inflammation, mainly induced by activated macrophages, is one of the most important events in the microenvironment of the injured spinal cord, and this process has recently attracted increasing attention [22,23]. Activated microglia/macrophages have either detrimental or beneficial effects on neural regeneration based on different subsets.…”

Effects and Mechanisms of Acupuncture Combined with Mesenchymal Stem Cell Transplantation on Neural Recovery after Spinal Cord Injury: Progress and Prospects

“…They also can improve axonal regeneration, inhibit demyelination while promoting myelin regeneration [ 16 , 69 – 72 ], and reconstruct functional neural networks [ 15 ]. It has been proposed that the therapeutic action of implanted MSC in SCI is based on the secretion of a variety of factors, such as NGF, NT-3, and BDNF [ 73 , 74 ]. Furthermore, paracrine immunomodulatory mediators secreted by MSCs can reduce harmful inflammation by inhibiting the differentiation of macrophages and microglia into neurotoxic, proinflammatory M1 subsets and promoting the generation of immunomodulatory M2 subsets which contribute to axonal growth and myelin regeneration [ 75 ].…”