Arabinogalactan in the Re-Epithelization and Glycocalyx Restoration Process of Rabbit Damaged Corneas

Abstract

 

Purpose:

 

Aim of this study was to investigate the corneal healing properties of a natural polysaccharide, arabinogalactan (AG), present in conifers of the genus Larix (Larch). The re-epithelization process of experimental corneal wounds was evaluated using microscopy.

 

Methods:

 

Corneal lesions were carried out on anesthetized rabbits removing corneal epithelium by applying of a paper disc soaked with n-heptanol. An animal group was treated three times a day with 5% AG aqueous solution, and another group was used as control (only vehicle). Corneal buttons were excised at predetermined time intervals and bisected for transmission electron microscopy (TEM). The specimens were fixed in Karnowsky solution, washed in phosphate buffer, postfixed in osmiun tetroxide and dehydrated in alcohol. The specimens were then washed with propylene oxide and embedded in epoxy resin. Ultrathin sections were cut by ultra-microtome, and examined with TEM. AG, pharma grade, was supplied by Opocrin S.p.A.

 

Results:

 

Physiological processes of corneal re-epithelization take place rapidly (48-72 h). TEM examination, used in this study, highlighted that 48 hours post wounding corneal surface treated with AG showed well formed microvilli and restored glycocalyx (Fig. A, m microvilli, g glycocalyx; scale bar = 1µm) while the superficial epithelium of control eyes did not display either microvilli or glycocalyx materials (Fig. B, scale bar = 1µm).

 

Conclusions:

 

AG increased the healing rate determining the re-epithelization and the restoration of natural ultrastructure already after 48 h post wounding.  

 

Keywords: cornea: epithelium • microscopy: electron microscopy • wound healing