Background:
Periodontal disease is the most common oral condition that affects the tissue
surrounding the teeth. The oral cavity is colonized by an impressive array of micro-organisms, many of
which can colonize the implants such as Guided Tissue Regeneration (GTR) often utilized in recovering
procedures that result in inflammation interfering with the bone regeneration.
Methods:
In the current study, a nano-hybrid GTR membrane is developed as a heliacal structure scaffold
with localized drug delivery function (Ibuprofen) as an anti-inflammatory agent. Polycaprolactone
(PCL) and a blend of Polyvinyl alcohol (PVA)/collagen (Col) (50/50) were electrospun by electrospinning.
Ibuprofen (Ibu) was loaded once in the PCL context and once in the hydrophilic portion
(PVA/Col).
Results:
The in vitro release behavior was investigated in each case. Chemical and physical properties
were studied for each item. Morphology investigation indicated a heliacal structure with the total average
diameter of 1266 nm consististing of porous pores with the average diameter of 256nm.
Conclusion:
The membranes indicated proper mechanical properties and appropriate biodegradation
rate as a potential GTR membrane. The controlled and sustained release of Ibu was obtained from both
PCL and PVA/COL loaded membranes. Kinetic model study indicated the following zero-order and
Higuchi models for the optimum case of PCL loaded and PVA/Col Ibu loaded scaffolds respectively.
It is believed that impaired extinction of fear memories is an underlying cause for the development of posttraumatic stress disorder (PTSD). Histone deacetylases (HDAC) are enzymes that modulate extinction by changing the chromatin structure and altering protein synthesis in the brain. Studies show that stress modifies both HDAC activity and cerebral cholinergic neurotransmission. The present work aims to evaluate the effect of sodium butyrate (NaBu), an HDAC inhibitor, on behavioral markers of extinction and biochemical changes in HDAC and acetylcholinesterase activity in the hippocampus. NaBu was administered for 7 days in a group of rats that were exposed to single prolonged stress (SPS), as a model for PTSD. Contextual fear conditioning was performed on the 8th day, and fear extinction was measured in the next 4 consecutive days. Other behavioral tests to measure anxiety, locomotor activity and working memory were performed for further interpretation of the results. Hippocampal acetylcholinesterase and HDAC activity were also measured through biochemical tests. Behavioral results showed that treatment with NaBu can reverse the SPS-induced extinction deficits. Biochemical data indicated that while SPS induced overactivity in hippocampal HDAC, it decreased acetylcholinesterase activity in the region. Both effects were reversed after NaBu treatment. It seems that at least part of extinction deficiency in SPS exposed rats is related to hypoacetylation of acetylcholinesterase in the hippocampus. Preemptive therapy with an HDAC inhibitor reverses this process and is worth further evaluation as a possible therapeutic approach in PTSD.
Coaxial electrospinning is a robust technique to prepare core-shell nanofibers for various biomedical applications such as tissue engineering. In this study, the coaxial electrospinning method was used to prepare two different core-shell nanofibers based on polycaprolactone/polyvinyl alcohol (PCL/PVA) and polycaprolactone/collagen (PCL/Col). The mechanical (e.g., shear viscosity and surface tension) and chemical properties of the nanofibers were characterized and compared. The results showed that PCL/Col nanofibers have higher stability and better coverage of the core compared to PCL/PVA nanofibers due to the high viscosity and low spinnability of the core polymer, collagen. The optimum voltage and feeding rate for the fabrication of nanofibers were found to be 16 kV and 1:3 (core:shell), respectively. Due to their secondary structure and their promising properties, PCL/Col nanofibers exhibited great potential for biomedical applications such as wound healing and drug delivery platforms.
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