5-FU had a broad therapeutic range, and the 5-FU implant showed only minor tissue reactions in conjunctiva at the surgical site. 5-FU is a possible candidate for controlled drug release.

. Purpose:  The use of biopolymers in peribulbar injection for controlled drug delivery provides alternative options to eyedrops and intravitreal or surgical methods. Polymerizable biopolymers are especially likely to have a role because of their particular properties. In liquid form, they can be easily injected into the target site and, after polymerization, they provide a prolonged and controlled release of the drug. This study was undertaken to demonstrate the suitability of a thermopolymerizable biopolymer poloxamer (Lutrol F127) for peribulbar injections and controlled drug release. Methods:  The toxicity of injected poloxamer compounds was evaluated by visual inspection and histological and immunohistochemical tissue evaluation. The release of marker substances such as 5(6)‐carboxyfluorescein (376 Da) or fluorescein isothiocyanate‐dextran (FITC‐dextran) (4−40 kDa) from poloxamer was used to simulate drug release and penetration into the eye using in vivo fluorometry. Results:  According to our clinical and pathological analyses, poloxamer was well tolerated in peribulbar injections and did not cause acute toxicity at the site of injection. The marker compounds were released from the site of injection during the first 24 hours. Conclusions:  Although poloxamer appears to be suitable for peribulbar injections, a more prolonged period of dissolution is desirable for clinical purposes.

Purpose To examine heat shock protein (HSP) expression in retinas of mice that lack brain derived neurotrophic factor (BDNF+/‐) and their wild type littermates (WT) at young and old age. Methods Eyes from 2‐ and 22‐months old WT and BDNF+/‐ mice (The Jackson Laboratory, Bar Harbor, ME, USA) were used. HSP 27 kDa (HSP27), 60 kDa (HSP60) and 70 kDa (HSP70) protein levels in retina were determined by Western blotting. Paraffin‐embedded retinal sections were immunostained for HSPs to determine their localisation and abundance in various retinal layers. Results Western blot analysis of the whole retina showed a 2‐fold increase in HSP27 and HSP60, and a 1.5‐fold increase in HSP70 in aged WT mice as compared to young mice. The lack of BDNF significantly upregulated HSPs expression in retina. Thus, young BDNF+/‐ mice had similar expression levels of HSPs in retina as in old WT mice, whereas a further increase in HSPs expression was observed in aged BDNF+/‐ mice as compared to young BDNF+/‐ mice. Conclusion Aging is associated with an increased expression of HSPs in the mouse retina. The lack of BDNF induces similar expression of stress‐related proteins in retina already at young age as it is seen at old age under normal BDNF levels.

Purpose Brain derived neurotrophic factor (BDNF) is essential for cell development, function and survival. Mammalian sirtuins (SIRT) are deacetylase enzymes that are known to play an important role in longevity. In the present study we aimed to compare SIRT1 and SIRT2 expression in retinas of mice that lack brain derived neurotrophic factor (BDNF+/‐) and their wild type littermates (WT) at young age in relation to cellular metabolism. Methods Eyes from 2‐months old WT and BDNF+/‐ mice (The Jackson Laboratory, Bar Harbor, ME, USA) were used. SIRT1 and SIRT2 protein levels in retina were determined by Western blotting. Paraffin‐embedded retinal sections were immunostained for SIRT1 and SIRT2 to determine their localisation and abundance in various retinal layers. Metabolic state of mouse retinal cells was assessed by measuring NAD+, NADH and total NAD levels using resazurin‐based assay. Results Western blot analysis of the whole retina showed that SIRT1 expression is similar in WT and BDNF+/‐ mice. However, there was a significant upregulation of SIRT2 protein level in BDNF+/‐ mice compared to WT littermates. Assessment of NAD+, NADH and total NAD levels showed similar cellular metabolic state in retinas of WT and BDNF+/‐ mice. Conclusion Our results indicate increased tubulin deacetylation in retinas of BDNF+/‐ mice, which is independent from cellular energy metabolism.