ABSTRACT
BACKGROUND: Carbon nanotubes (CNTs) have a large variety of applications in tissue engineering and biomedical devices. The biocompatibility and cytotoxicity of CNTs have been studied widely, however, up until now; there was uncertainty on how nanosized materials behave in the human body and stem cells. The current study describes the functionalized carbon nanotubes on adipose-derived stem cells (ADSCs) for viability and proliferation purposes in vitro. MATERIALS AND METHODS: After chemical modification of the CNTs, the ADSCs were cultured in Dulbecco's Modified Eagle's. Medium (DMEM) having doses of 0.1, 1, 10, 20, 50, and 100 µg/ml of CNTs. On the third and seventh days of the experiment, the cellular viability, proliferation, and stemness were determined, using the MTT, trypan Blue, and flow cytometry assays in variable CNTs dosage. RESULTS: In doses of 0.1 and 1 µg/ml, the expression of the surface markers were similar to the control groups on day three, but decreased in higher dosages on day seven. The viability of both groups was the same on day three, but in comparison to the control groups, was found to decrease in the higher dosages on day seven. CONCLUSION: The effect of CNTs on the viability and proliferation of ADSCs is a function of time and the doses used. Through further investigation by using these particles, we expect that we should be able to increase the viability and proliferation of ADSCs.
ABSTRACT
Neonatal X-irradiation of central nervous system (CNS) tissue markedly reduces the glial population in the irradiated area. Previous in vivo studies have demonstrated regenerative success of adult dorsal root ganglion (DRG) neurons into the neonatally-irradiated spinal cord. The present study was undertaken to determine whether these results could be replicated in an in vitro environment. The lumbosacral spinal cord of anaesthetised Wistar rat pups, aged between 1 and 5 days, was subjected to a single dose (40 Gray) of X-irradiation. A sham-irradiated group acted as controls. Rats were allowed to reach adulthood before being killed. Their lumbosacral spinal cords were dissected out and processed for sectioning in a cryostat. Cryosections (10 microm-thick) of the spinal cord tissue were picked up on sterile glass coverslips and used as substrates for culturing dissociated adult DRG neurons. After an appropriate incubation period, cultures were fixed in 2% paraformaldehyde and immunolabelled to visualise both the spinal cord substrate using anti-glial fibrillary acidic protein (GFAP) and the growing DRG neurons using anti-growth associated protein (GAP-43). Successful growth of DRG neurites was observed on irradiated, but not on non-irradiated, sections of spinal cord. Thus, neonatal X-irradiation of spinal cord tissue appears to alter its environment such that it can later support, rather than inhibit, axonal regeneration. It is suggested that this alteration may be due, at least in part, to depletion in the number of and/or a change in the characteristics of the glial cells.
