Inhibition effect of tetrandrine on haze formation after Epi-LASIK surgery in rabbits

Evaluating the Efficacy of Polyglycolic Acid-Loading Tetrandrine Nanoparticles in the Treatment of Dry Eye

INTRODUCTION

Dry eye disease (DED) is a multifactor-induced disease accompanied by increased osmolarity of the tear film and inflammation of the ocular surface. Traditional anti-inflammation agent corticosteroids applied in DED treatment could result in high intraocular pressure, especially in long-term treatment. Therefore, we explored a nano drug that aimed to block the formation pathway of DED which had anti-inflammatory, sustained release, and good biocompatibility characteristics in this study.

METHODS

We prepared a novel nanomedicine (Tet-ATS@PLGA) by the thin film dispersion-hydration ultrasonic method and detected its nanostructure, particle size, and zeta potential. Flow cytometry was used to detect the cell survival rate of each group after 24 h of drug treatment on inflammed Statens Seruminstitut Rabbit Corneal (SIRC) cells. Observed and recorded corneal epithelial staining, tear film rupture time, and Schirmer test to detect tear secretion on the ocular surface of rabbits. The corneal epithelial thickness, morphology, and number of bulbar conjunctival goblet cells were recorded by H&E staining. Finally, we detected the expression of VEGF, IL-1β, PGE2, and TNF-α by cellular immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The encapsulation efficiency and drug loading of Tet-ATS@PLGA were 79.85% and 32.47%, respectively. At eye surface temperature, Tet can easily release from Tet-ATS@PLGA while that it was difficult to release at storage temperature and room temperature. After 2 weeks medication, Tet-ATS@PLGA can effectively improve the tear film rupture time and tear secretion time in a DED model (p <0.05). Compared with the normal group (62.34 ± 4.86 mm), the thickness of corneal epithelium in ATS (29.47 ± 3.21 mm), Tet-ATS (46.23 ± 2.87 mm), and Tet-ATS@PLGA (55.76 ± 3.95 mm) gradually increased. Furthermore, the flow cytometry indicated that Tet-ATS@PLGA can effectively promote the apoptosis of inflammatory SIRC cells, and the cellular immunofluorescence and ELISA experiments showed that the expression intensity of inflammatory factors such as VEGF, IL-1β, PGE2, and TNF-α decreased in this process. Interestingly, Tet also had the effect of reducing intraocular pressure.

CONCLUSION

Tet-ATS@PLGA can effectively promote the apoptosis of inflammatory corneal epithelial cells, thus inhibiting the expression of inflammatory factors to block the formation of DED and improve the secretion of tear on the ocular surface.

Combination Nanotherapeutics for Dry Eye Disease Treatment in a Rabbit Model

Purpose

Anti-inflammation is essential for dry eye disease. Traditional anti-inflammation agent corticosteroids applied in dry eye disease (DED) treatment could result in high intraocular pressure, especially in long-term treatment. Thus, we have prepared a liposome loading 1-bromoheptadecafluorooctane and tetrandrine (PFOB@LIP-Tet) to treat DED via anti-inflammation that hardly affects intraocular pressure in this study, which provided another therapy strategy for dry eye disease.

Methods

We firstly detected the physicochemical properties of PFOB@LIP-Tet. Next, we tested the biosafety of synthesized liposomes for corneal epithelium. Then, we explored the accumulations and distribution of PFOB@LIP-Tet both in cellular and animal models. And then, we assessed the therapeutic effects of PFOB@LIP-Tet formulations by laboratory and clinical examinations. Last, we examined the changes in eye pressure before and after treatment.

Results

PFOB@LIP-Tet and Tet showed a characteristic absorption peak at 282 nm while PFOB@LIP did not. Large amounts of PFOB@LIP-Tet remained on the ocular surface and accumulated in the corneal epithelial cells in DED rabbits. Corneal staining scores of DED rabbits respectively treated by ATS, PFOB@LIP-ATS, Tet-ATS and PFOB@LIP-Tet-ATS for seven days were 3.7±0.5, 3.2±0.4, 1.5±0.5 and 0.5±0.5. The expressions of related cytokines were correspondingly downregulated significantly, indicating that the inflammation of DED was successfully suppressed. The intraocular pressure changes of DED rabbits before and after treatment by PFOB@LIP-Tet showed no statistical significance.

Conclusion

We successfully synthesized PFOB@LIP-Tet, and it could effectively treat dry eye disease via anti-inflammation but hardly affected the intraocular pressure.

[Association between hepatocyte growth factor in tears and corneal haze in rabbits early after epipolis laser in situ keratomileusis]

OBJECTIVE

To study the dynamic changes of levels of hepatocyte growth factor (HGF) in tears and their association with corneal haze in rabbits early after epipolis laser in situ keratomileusis (Epi-LASIK).

METHODS

Twenty-four New Zealand rabbits received Epi-LASIK with an ablation depth of 100 µm in one eye and of 150 µm in the other eye. Before and at 3, 7, 14, and 30 days after the surgery, the level of HGF in tears collected from the rabbits was measured using enzyme-linked immunosorbent assay (ELISA), and corneal haze was graded after surgery.

RESULTS

In all the rabbits, corneal epithelium healing occurred in 3 to 5 days after Epi-LASIK. Corneal haze appeared 3 days postoperatively in the rabbits accompanied by increased levels of HGF in tears. At 3, 7, 14, and 30 days after the surgery, the rabbits with an ablation depth of 150 µm showed more obvious corneal haze (P<0.05) and significantly higher levels of HGF in tears than those with an ablation depth of 100 µm (P<0.05).

CONCLUSION

In rabbits receiving Epi-LASIK, HGF levels in tears and the grade of corneal haze show a positive correlation early after the surgery and are both related with the depth of ablation.