Adult dendritic arbors and spines can be modulated by environment and gonadal hormones that have been reported to affect also those of hippocampal and prefrontal cortical neurons. Here we investigated whether female gonadal hormones and estrous cycle alter the dendrites of primary cortical neurons. We employed intracellular dye injection in semifixed brain slices and 3-dimensional reconstruction to study the dendritic arbors and spines of the major cortical output cells, layer III and V pyramidal neurons, during different stages of the estrous cycle. Dendritic spines of both pyramidal neurons were more numerous during proestrus than estrus and diestrus, whereas dendritic arbors remained unaffected. Ovariohysterectomy (OHE) reduced dendritic spines by 24–30% in 2 weeks, whereas subcutaneous estrogen or progesterone supplement restored it to normal estrous/diestrous level in 14 days; neither treatment affected the dendritic arbors. Reduction of dendritic spines following OHE was associated with decrease of PSD-95 suggesting decrease of excitatory synapses. Thus, fluctuation of gonadal hormones during the female sex cycle is likely to modulate primary cortical functions and loss of gonadal hormones for instance following menopause might compromise cortical function, and the effect could be reversed by exogenous female sex hormones.

Nerve conduits are often used in combination with bioactive molecules and stem cells to enhance peripheral nerve regeneration. In this study, the acidic fibroblast growth factor 1 (FGF1) was immobilized onto the microporous/micropatterned poly (D, L-lactic acid) (PLA) nerve conduits after open air plasma treatment. PLA substrates grafted with chitosan in the presence of a small amount of gold nanoparticles (nano Au) showed a protective effect on the activity of the immobilized FGF1 in vitro. Different conduits were tested for their ability to bridge a 15 mm critical gap defect in a rat sciatic nerve injury model. Axon regeneration and functional recovery were evaluated by histology, walking track analysis and electrophysiology. Among different conduits, PLA conduits grafted with chitosan–nano Au and the FGF1 after plasma activation had the greatest regeneration capacity and functional recovery in the experimental animals. When the above conduit was seeded with aligned neural stem cells, the efficacy was further enhanced and it approached that of the autograft group. This work suggested that microporous/micropatterned nerve conduits containing bioactive growth factors may be successfully fabricated by micropatterning techniques, open plasma activation, and immobilization, which, combined with aligned stem cells, may synergistically contribute to the regeneration of the severely damaged peripheral nerve.

Bone marrow stromal cells are multipotential cells that can be induced to differentiate into osteoblasts, chondrocytes, myocytes and adipocytes in different microenvironments. Recent studies revealed that bone marrow stromal cells could improve neurological deficits of various damages or diseases of the central nervous system such as Parkinson's disease, brain trauma, spinal cord injury and multiple sclerosis, and promote glia-axonal remodeling in animal brain subjected to an experimentally induced stroke. In the present study, bone marrow stromal cells were intracerebrally transplanted into the cerebrum following a transient middle cerebral artery occlusion. Our aim was to find out whether the bone marrow stromal cells could survive and express neural phenotypic proteins and, in addition, whether they could restore the behavioral and functional deficits of the cerebral ischemic rats. Our results demonstrated that transplanted bone marrow stromal cells survived and migrated to areas around the lesion site. Some of them exhibited marker proteins of astrocytes and oligodendrocytes. Bone marrow stromal cell implantation significantly reduced the transient middle cerebral artery occlusion-induced cortical loss and thinning of the white matter and enhanced cortical β-III-tubulin immunoreactivity. Rats implanted with bone marrow stromal cells showed significant improvement in their performance of elevated body swing test and forelimb footprint analysis and only transient recovery of the adhesive-removal test. Our data support bone marrow stromal cells as a valuable source of autologous or allogenic donor cells for transplantation to improve the outcome following cerebral ischemia.

Hepatic encephalopathy (HE) is a reversible neuropsychiatric syndrome associated with acute and chronic liver diseases. It includes a number of neuropsychiatric disturbances including impaired motor activity and coordination, intellectual and cognitive function.

Proximal nerve injury often requires nerve transfer to restore function. Here we evaluated the efficacy of end‐to‐end and end‐to‐side neurorrhaphy of rat musculocutaneous nerve, the recipient, to ulnar nerve, the donor. The donor was transected for end‐to‐end, while an epineurial window was exposed for end‐to‐side neurorrhaphy. Retrograde tracing showed that 70% donor motor and sensory neurons grew into the recipient 3 months following end‐to‐end neurorrhaphy compared to 40–50% at 6 months following end‐to‐side neurorrhaphy. In end‐to‐end neurorrhaphy, regenerating axons appeared as thick fibers which regained diameters comparable to those of controls in 3–4 months. However, end‐to‐side neurorrhaphy induced slow sprouting fibers of mostly thin collaterals that barely approached control diameters by 6 months. The motor end plates regained their control density at 4 months following end‐to‐end but remained low 6 months following end‐to‐side neurorrhaphy. The short‐latency compound muscle action potential, typical of that of control, was readily restored following end‐to‐end neurorrhaphy. End‐to‐side neurorrhaphy had low amplitude and wide‐ranging latency at 4 months and failed to regain control sizes by 6 months. Grooming test recovered successfully at 3 and 6 months following end‐to‐end and end‐to‐side neurorrhaphy, respectively, suggesting that powerful muscle was not required. In short, both neurorrhaphies resulted in functional recovery but end‐to‐end neurorrhaphy was quicker and better, albeit at the expense of donor function. End‐to‐side neurorrhaphy supplemented with factors to overcome the slow collateral sprouting and weak motor recovery may warrant further exploration.