PDLLA/PRGD/β‐TCP conduits build the neurotrophin‐rich microenvironment suppressing the oxidative stress and promoting the sciatic nerve regeneration

Abstract

A novel nerve guidance conduit comprising poly{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]} (PRGD), poly (d,l-lactic acid) (PDLLA) and β-tricalcium phosphate (β-TCP) was constructed to facilitate the peripheral nerve regeneration. From the comparative study, PDLLA/PRGD/β-TCP conduit achieved the best recovery in regard of the ultrastructure observation and the SFI evaluation. At the first stage of the injury (7 days), the maximum expression augments in ZnSOD (6.4 folds) and GPX4 (6.8 folds) were observed in PDLLA/PRGD/β-TCP group; while striking rise in actin (6.8 folds), tubulin (5.6 folds), and ERM components expressions were observed later (35 days). Meanwhile, compared with PDLLA and PDLLA/PRGD conduits, PDLLA/PRGD/β-TCP conduits achieved the highest local nerve growth factor (NGF) content and an accumulating BDNF content. We speculated that addition of RGD and β-TCP in the composites were the main positive factors to build the microenvironment rich in NGF and BDNF, which help to counteract with the oxidative stress and to boost the cytoskeletal protein expressions. Therefore, PDLLA/PRGD/β-TCP could be promising composites used in peripheral nerve regeneration.

Collagen/β‐TCP nerve guidance conduits promote facial nerve regeneration in mini‐swine and the underlying biological mechanism: A pilot in vivo study

“…Interestingly, the regenerative effects achieved in the collagen/β‐TCP groups were superior to that in the collagen groups. This outcome came in a good agreement with others, in which the addition of β‐TCP added to the PRGD/PDLLA conduit‐enhanced sciatic nerve regeneration …”

Effect of a nerve graft substitute single-walled carbon nanotubes on rat pheochromocytoma cells

“…It was increased to more than 10 folds in the 100 µg/mL group, while it was increased to less than 6 folds in the group of 25 µg/mL. SWNTs-COOH treatments lead to more elevation in the GST expression in the 100 µg/mL after 24 h. [24] demonstrated the oxidative stress responses to carboxylic acid functionalized SWNTs on Similarly, Qiu et al [25] verified the rapid elevation of mRNA expressions of CAT, SOD, GPx after the nerve damaged to counteract oxidative stress. Therefore, the antioxidant system in neuron cells was greatly induced when cells were co-cultured with SWNTs in the present study.…”

Preparation and characterization of GRGDY modified poly(dl-lactic acid)/hydroxyapatite porous composite

“…Studies have shown that cell adhesion and growth was improved by adding a small amount of GRGDY. 11,12 of hydroxyapatite, interface bonding deteriorated and poor interfacial compatibility. The main reason is the lack of effective adhesion between HA and PDLLA interface.…”