Phycocyanin/PEG-b-(PG-g-PEI) attenuated hepatic ischemia/reperfusion-induced pancreatic islet injury and enlarged islet functionality

Abstract

Background

Hepatic ischemia/reperfusion-induced pancreatic islet injury (HI/RIPII) was an important pathophysiological phenomenon in clinics. In the present study, we observed the effects of phycocyanin on HI/RIPII. However, the half-life of phycocyanin was extremely short and limited its use in vivo.

Materials and methods

In order to overcome this shortcoming, poly(ethylene glycol)-b-(poly(l-glutamic acid)-g-polyethylenimine) (PEG-b-(PG-g-PEI)) was synthesized and estimated as a nanocarrier for lengthening delivery of phycocyanin through the abdominal subcutaneous injection in rats. Phycocyanin (isoelectric point=4.3) was encapsulated with PEG-b-(PG-g-PEI) via electrostatic interactions at pH 7.4.

Results

In vitro phycocyanin was fast and efficiently encapsulated and showing efficient loading and sustained release. In vivo the anti-HI/RIPII function of phycocyanin/PEG-b-(PG-g-PEI) complex was surveyed in rats using free phycocyanin as the controls, and the results showed that phycocyanin/PEG-b-(PG-g-PEI) complex reduced HI/RIPII property and enlarged islet functionality.

Conclusion

These results suggested that PEG-b-(PG-g-PEI) might be treated as a potential phycocyanin nanocarrier.

Keywords:

• phycocyanin
• PEG-b-(PG-g-PEI)
• HI/RIPII
• pancreatic islets

Supplementary materials

Figure S1 The synthesis of PEG-b-(PG-g-PEI).

Abbreviations: BLG, γ-benzyl l-glutamate; BLG-NCA, γ-benzyl l-glutamate-N-carboxyanhydride; mPEG-NH₂, methoxy poly(ethylene glycol) amine; PBLG, poly(γ-benzyl l-glutamate); PEG-b-(PG-g-PEI), poly(ethylene glycol)-b-(poly(l-glutamic acid)-g-polyethylenimine).

Figure S2 Characterization of PEG-b-(PG-g-PEI) and phycocyanin/PEG-b-(PG-g-PEI).

Notes: (A) ¹H NMR spectra of PEG-b-PBLG (a) and PEG-b-(PG-g-PEI) (b); (B) TEM image of PEG-b-PBLG and phycocyanin/PEG-b-(PG-g-PEI); (C) cellular viability of HIT-T15 cells cultured with different concentrations of PEG-b-(PG-g-PEI); (D) diameter of PEG-b-(PG-g-PEI) (left) and phycocyanin/PEG-b-(PG-g-PEI) complexes (right) in PB.

Abbreviations: ¹H NMR, ¹H-nuclear magnetic resonance; PBLG, poly(γ-benzyl l-glutamate); PEG-b-(PG-g-PEI), poly(ethylene glycol)-b-(poly(l-glutamic acid)-g-polyethyl-enimine); TEM, transmission electron microscopy.

Acknowledgments

This study was financially supported by the Science and Technology Planning Project of Jiaxing, Zhejiang Province (2017AY33076).

Disclosure

This study was supported by the Zhejiang Province Nature Fund, Zhejiang Province (LY19B040003, Fei Tong). The authors report no other conflicts of interest in this work.

Author contributions

All authors contributed equally to this work and share equal responsibility as the first author. All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.