Arabinogalactan as active compound in the management of corneal wounds: In vitro toxicity and in vivo investigations on rabbits

ABSTRACT: Purpose: Aims of the present investigation were to prove that natural polysaccharide arabinogalactan (AG) is well tolerated after ocular administration and exerts a high restoring effect on corneal epithelium abrasions. Materials and Methods: AG interactions with corneal cells, as well as its effect on their proliferation, were evaluated employing rabbit corneal epithelial cell cultures. The effects due to the presence of benzalkonium chloride (BAK) were also studied on cell cultures, ex vivo on rabbit isolated corneas, evaluating the hydration level, and on the healing rate of experimental corneal wounds in rabbits. Furthermore, the healing process of corneal lesions treated with an experimental 5.0% AG solution was studied and compared with those obtained applying solutions of hyaluronic acid and tamarind seed polysaccharide, both chosen as a reference by virtue of their well-known adjuvant properties on corneal trophism; the study was carried out by light and transmission electron microscopy. Results: BAK showed toxic effects on corneal epithelium in all experiments. AG proved to stimulate the growth of the corneal epithelial cells by interacting at the level of the cell plasma membrane. The microscopy observations of the epithelial surface of AG-treated damaged corneas revealed a well-restored and histologically organized ultrastructure characterized by fully formed microvilli and glycocalyx; the healing process resulted faster with respect to spontaneously recovered untreated corneas. Conclusion: Our results suggest that AG can interact with corneal epithelial cells without any toxic side effect; moreover, it proved to stimulate cell proliferation, thus promoting tissue re-epithelialization and reorganization just 48hr post-woundin

Autoradiographic localization and binding study of benzodiazepines receptor sites in carp brain (Cyprinus carpio L.)

This study demonstrates, for the first time, by both autoradiography and binding assay that [3H]Ro 15-1788 binds to carp brain with a high degree of anatomical selectivity. Saturation binding of the radioligand was determined in seven anatomically defined regions and suggested the presence of one class of binding sites (Type I-lke). In general, there was a good correlation between the autoradiographic and the binding data. By far, the optic tectum and the vagal, facial, and glossopharyngeal lobes showed the majority of [3H]Ro 15-1788 binding sites. Low to negative concentration of binding sites was detected in the cerebellum. The location of [3H]Ro 15-1788 binding sites in particular brain regions, indicates that benzodiazepine receptors could be associated with pathways involved in the control of basic central functions as spatial learning acquisition and retention, and feeding behaviour