Epidural scarring occurs inevitably in the defect after spinal laminectomy

and thus how to prevent or reduce it becomes a challenging topic. In the present study

an injectable hydrogel and its dexamethasone (DEX)-loaded hydrogel systems were adopted to prevent epidural scarring in a postlaminectomy rat model. The hydrogel system composed of poly(D

L-lactic acid-

co

-glycolic acid)-poly(ethylene glycol)-poly(D

L-lactic acid-

co

-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers was a free-flowing sol at room temperature

and spontaneously turned into a semi-solid gel at body temperature. A lumbar 3 total laminectomy was performed on Sprague Dawley (SD) rats

and the efficacy of the injectable hydrogel with or without drugs in preventing epidural scar formation was evaluated

via

the gross anatomical observation and histological examination at one month post-surgery. The results demonstrate that the use of hydrogel alone reduced epidural scarring significantly

whereas the efficacy of the DEX-loaded hydrogels presented an irregular dose-dependency of drug and even the inappropriate drug doses resulted in the negative results. Therefore

the present study confirms that the PLGA-PEGPLGA hydrogel holds potential as a barrier device to decrease peridural scarring

and reveals that the sustained delivery of the steroid hormone DEX to prevent surgery-related adhesions in the laminectomy defect is complex. Moreover

our

in vivo

studies also remind the researchers to pay attention to the irregular dose-dependency of the hormone drugs.