Intravitreal injection of the synthetic peptide LyeTx I b, derived from a spider toxin, into the rabbit eye is safe and prevents neovascularization in a chorioallantoic membrane model

 

Flavia Rodrigues da Silva¹, Mayara Rodrigues Brandão de Paiva¹, Lays Fernanda Nunes Dourado¹, Rummenigge Oliveira Silva¹, Carolina Nunes da Silva¹, Bruna Lopes da Costa¹, Cibele Rodrigues Toledo¹, Maria Elena de Lima², Armando da Silva-Cunha¹

 

1 Faculdade de Farmácia, Universidade Federal de Minas Gerais, Av Antônio Carlos, 6627, 2nd Floor, Room 2031, Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brazil

2 Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil

 

ABSTRACT

Background:

The great diversity of molecules found in spider venoms include amino acids, polyamines, proteins and peptides, among others. Some of these compounds can interact with different neuronal receptors and ion channels including those present in the ocular system. To study potential toxicity and safety of intravitreal injection in rabbits of LyeTx I b, a synthetic peptide derived from the toxin LyeTx I found in venom from the spider Lycosa eritrognatha and to evaluate the angiogenic activity on a CAM model.

 

Methods:

ARPE-19 cells were treated with LyeTx I b (0.36; 0.54; 0.72; 2.89; 4.34 or 9.06 μM). In this study, New Zealand rabbits were used. LyeTx I b (2.89 μM) labeled with FITC dissolved in PBS, or only PBS, were injected into vitreous humor. Electroretinogram (ERG) was recorded 1 day before injection and at 7,14 and 28 days post-injection. Clinical examination of the retina was conducted through tonometer and eye fundus after ERG. Eyes were enucleated and retinas were prepared for histology in order to assess retinal structure. CAMs were exposed to LyeTx I b (0.54; 0.72; 2.17 or 2.89 μM).

 

Results:

ARPE-19 cells exposed to LyeTx I b showed cell viability at the same levels of the control. The fluorescence of LyeTx I b labeled with FITC indicated its retinal localization. Our findings indicate ERG responses from rats injected in the eye with LyeTx I b were very similar to the corresponding responses of those animals injected only with vehicle. Clinical examination found no alterations of intraocular pressure or retinal integrity. No histological damage in retinal layers was observed. CAM presented reduced neovascularization when exposed to LyeTx I b.

 

Conclusions:

Intravitreal injection of LyeTx I b is safe for use in the rabbit eye and prevents neovascularization in the CAM model, at Bevacizumab levels. These findings support intravitreal LyeTx l b as a good candidate to develop future alternative treatment for the retina in neovascularization diseases.

 

Keywords: Lycosa eritrognatha; LyeTx I b; intravitreal injection; Retinal diseases; Toxicity; Retinal neovascularization

 

Received: May 07, 2018.

Accepted: October 31, 2018.

Published: November 21, 2018.

 

Correspondence: dra.flaviarodrigues@hotmail.com

 

Authors’ contributions

FRS designed the study and conducted CAM (Chorio-allantoic Membrane), Tonometer, Electroretinogram recordings and Histological analysis experiments; LFND and ROS performed Tonometer, Eye Fundus, Electroretinogram recordings and Histological slices; LFND contributed analysis and interpretation of data; CSN made substantial contributions to acquisition, analysis and interpretation of FITC experiment and critical revision of the manuscript for scientific and revised the manuscript critically for important intellectual content; Intravitreal injections were performed by BLC and contributed with Electroretinogram, eye fundus and critical review; Cell culture experiment was conducted by CRT; MELP contributed peptide synthesis and made substantial and critical revision of the manuscript for scientific content and revised the manuscript critically for important intellectual content; ASCJ coordinated the study, provided the necessary infrastructure for the experiments and made substantial and critical revision of the manuscript for scientific content and revised the manuscript critically for important intellectual content. Results were analyzed by FRS, MBP, CRT and CSN. The article was written by FRS and all other authors revised the data and discussed the manuscript. All authors read and approved the final manuscript.

 

Competing interests

The authors declare that they have no competing interests.