GFP-OBNSCs had survived for >8 weeks after engraftment and were differentiated into neurons, astrocytes and oligodendrocytes, The engrafted cells were distributed throughout gray and white matter of the cord with no evidence of abnormal morphology or any mass formation indicative of tumorigenesis. However, the engrafted cells failed to restore lost sensory and motor functions as evident from behavioral analysis using the BBB score test.

Neural stem cells (NSCs) are multipotent self-renewing cells that could be used in cellular-based therapy for a wide variety of neurodegenerative diseases including Alzheimer's diseases (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS). Being multipotent in nature, they are practically capable of giving rise to major cell types of the nervous tissue including neurons, astrocytes, and oligodendrocytes. This is in marked contrast to neural progenitor cells which are committed to a specific lineage fate. In previous studies, we have demonstrated the ability of NSCs isolated from human olfactory bulb (OB) to survive, proliferate, differentiate, and restore cognitive and motor deficits associated with AD, and PD rat models, respectively. The use of carbon nanotubes (CNTs) to enhance the survivability and differentiation potential of NSCs following their in vivo engraftment have been recently suggested. Here, in order to assess the ability of CNTs to enhance the therapeutic potential of human OBNSCs for restoring cognitive deficits and neurodegenerative lesions, we co-engrafted CNTs and human OBNSCs in TMT-neurodegeneration rat model. The present study revealed that engrafted human OBNSCS-CNTs restored cognitive deficits, and neurodegenerative changes associated with TMT-induced rat neurodegeneration model. Moreover, the CNTs seemed to provide a support for engrafted OBNSCs, with increasing their tendency to differentiate into neurons rather than into glia cells. The present study indicate the marked ability of CNTs to enhance the therapeutic potential of human OBNSCs which qualify this novel therapeutic paradigm as a promising candidate for cell-based therapy of different neurodegenerative diseases.

In the present study we developed an excitotoxic spinal cord injury (SCI) model using kainic acid (KA) to evaluate of the therapeutic potential of human olfactory bulb neural stem cells (h-OBNSCs) for spinal cord injury (SCI). In a previous study, we assessed the therapeutic potential of these cells for SCI; all transplanted animals showed successful engraftment. These cells differentiated predominantly as astrocytes, not motor neurons, so no improvement in motor functions was detected. In the current study we used estrogen as neuroprotective therapy before transplantation of OBNSCs to preserve some of endogenous neurons and enhance the differentiation of these cells towards neurons. The present work demonstrated that the h-GFP-OBNSCs were able to survive for more than eight weeks after sub-acute transplantation into injured spinal cord. Stereological quantification of OBNSCs showed approximately a 2.38-fold increase in the initial cell population transplanted. 40.91% of OBNSCs showed differentiation along the neuronal lineages, which was the predominant fate of these cells. 36.36% of the cells differentiated into mature astrocytes; meanwhile 22.73% of the cells differentiated into oligodendrocytes. Improvement in motor functions was also detected after cell transplantation.Spinal cord injury (SCI) is any damage to the spinal cord leading to a change, either temporary or permanent, in the normal motor, sensory and autonomic function of the cord. Globally over 20 million individuals suffer from paralysis caused by SCI (Lee et al., 2014). The number of SCI patients is continually increasing, and each year, an estimated 180,000 individuals over the world get a new injury (Lee et al., 2014). The severity of injury and its location on the spinal cord determine the symptoms of SCI. Symptoms may vary from partial to complete loss of sensory and motor function of the arms, legs and/or body. Disturbance of breathing, heart rate, blood pressure, bowel or bladder controls are considered the most severe forms of the injury (Yılmaz et al. 2014). The main causes of SCI are motor vehicle accidents, acts of violence, sports injuries, and some diseases such as osteoporosis, arthritis and cancer of the spinal cord (Bellucci et al., 2015 and McCaughey et al., 2016). The pathophysiology of spinal cord injury is best described as bi-phasic, involving both a primary (cause of injury) and secondary phase. The primary phase of injury followed by rapid and progressive secondary injury events include physiological, anatomical and neurochemical changes leading to permanent neuronal cell death and glial scar and syrinx formation (Choo et al., 2007). Various models of SCI are based on surgical methods, which are determined by the aims of the particular research (Akhtar et al., 2008). In this study the KA was used to induce an excitotoxic SCI model. The induction of KA as a very effective excitotoxin was first done by Olney, (1974). KA has been widely utilized as a specific agonist for ionotropic glutamate receptors (iGluRs) to mimic the effe...