Tissues engineering has gained a lot of interest, since this approach has potential to restore lost tooth-supporting structures, which is one of the biggest challenges for periodontal treatment. In this study, we aimed to develop an in situ hydrogel that could conceivably support and promote the regeneration of lost periodontal tissues. The hydrogel was fabricated from methacrylated hyaluronic acid (MeHA). Fragment/short-chain hyaluronic acid (sHA) was incorporated in this hydrogel to encourage the bio-synergistic effects of two different molecular weights of hyaluronic acid. The physical properties of the hydrogel system, including gelation time, mechanical profile, swelling and degrading behavior, etc., were tested to assess the effect of incorporated sHA. Additionally, the biological properties of the hydrogels were performed in both in vitro and in vivo models. The results revealed that sHA slightly interfered with some behaviors of networking systems; however, the overall properties were not significantly changed compared to the base MeHA hydrogel. In addition, all hydrogel formulations were found to be compatible with oral tissues in both in vitro and in vivo models. Therefore, this HA-based hydrogel could be a promising delivery system for low molecular weight macromolecules. Further, this approach could be translated into the clinical applications for dental tissue regeneration.

Asiatic acid (AA), a natural triterpene found in Centalla asiatica, possesses polypharmacological properties that can contribute to the treatment and prophylaxis of various diseases. However, its hydrophobic nature and rapid metabolic rate lead to poor bioavailability. The aim of this research was to develop a thermoresponsive nanogel from hyaluronic acid (HA) for solubility and stability enhancement of AA. Poly(N-isopropylacrylamide) (pNIPAM) was conjugated onto HA using a carbodiimide reaction followed by ¹H NMR characterization. pNIPAM-grafted HA (HA-pNIPAM) nanogels were prepared with three concentrations of polymer, 0.1, 0.15 and 0.25% w/v, in water by the sonication method. AA was loaded into the nanogel by the incubation method. Size, morphology, AA loading capacity and encapsulation efficiency (EE) were analyzed. In vitro cytocompatibility was evaluated in fibroblast L-929 cells using the PrestoBlue assay. Single-dose toxicity was studied using rats. HA-pNIPAM nanogels at a 4.88% grafting degree showed reversible thermo-responsive behavior. All nanogel formulations could significantly increase AA water solubility and the stability was higher in nanogels prepared with high polymer concentrations over 180 days. The cell culture study showed that 12.5 µM AA in nanogel formulations was considered non-toxic to the L-929 cells; however, a dose-dependent cytotoxic effect was observed at higher AA-loaded concentrations. In vivo study proved the non-toxic effect of AA loaded in HA-pNIPAM nanogels compared with the control. Taken together, HA-pNIPAM nanogel is a promising biocompatible delivery system both in vitro and in vivo for hydrophobic AA molecules.

Background: Tiletamine/zolazepam is a dissociative anesthetic combination commonly used in small animals but information is limited in rats. The alpha‐2 agonist, dexmedetomidine, has gained popularity in laboratory animal anesthesia. Tramadol is a weak opioid mu agonist. The aim of this study was to assess whether the tiletamine/zolazepam/dexmedetomidine (ZD) combination effectively provides a surgical anesthesia plane comparable to tiletamine/zolazepam/dexmedetomidine with tramadol (ZDT) in a minor procedure in rats.Methods: Rats were induced with ZD or ZDT. After the loss of paw withdrawal, a small incision was made on the rats’ left thighs as a surgical stimulus. Rats were maintained under a surgical anesthesia plane by assessing the loss of the paw withdrawal reflex for 45 minutes, then atipamezole was administered. Monitored anesthesia parameters included: (a) physiological parameters – pulse rate (PR), respiratory rate (RR), tissue oxygen saturation (%SpO₂), and body temperature; (b) duration parameters – induction time, onset and duration of surgical anesthesia plane, onset of recovery, and recovery time.Results: PR was significantly lower at 10 minutes in ZD and 5 minutes in ZDT groups. No difference was observed for RR, %SpO₂, and body temperature. Likewise, there were no differences for duration parameters: induction time was less than 3 minutes; onset and duration of surgical anesthesia plane were approximately 5 and 45 minutes, respectively; onset of recovery (time to move) was 51 minutes; and recovery time was 52 minutes, respectively.Conclusion: These data suggest the ZD combination provides a surgical anesthesia plane comparable to ZDT in a rat incisional pain model.

Asiatic acid (AA) is a compound isolated from Centella asiatica, which possesses significant antihypertensive activity. Several studies have shown that its hypertensive activity can be attributed to various mechanisms, such as Angiotensin-Converting-Enzyme (ACE) inhibition in the renin-angiotensin-aldosterone system (RAAS) pathway. Meanwhile, palm oil (PO) is an antioxidant, which has proven to have synergistic effects with the compound by preventing arterial thrombosis and atherosclerosis. Despite these synergistic effects, AA dosage in antihypertensive therapy has been reported to be relatively high compared to the common synthetic drug captopril. Therefore, this study aimed to produce spray-dried powder of nanoemulsion to enhance the solubility of AA, decrease the possibility of oxidation, and increase its activity. Redispersed AA nanoparticles were also successfully obtained during the synthesis process. Several evaluations were carried out, including particle size, particle distribution, zeta potential, cell viability, and antihypertensive activity in rats to ensure the improvement of physicochemical characteristics and activity as antihypertensive agent. The results showed that AA succeeded in forming nanoemulsion with excipients. In addition, it was encapsulated in a maltodextrin carrier, exhibiting good physicochemical characteristics and safety to the Caco-2 cells. The redispersion of the spray-dried powder yielded nanoparticles with a size of 217.4 ± 10.196 nm. The spray-dried nanoemulsion of AA also had faster effect than non-formulated AA (raw powder) in lowering the blood pressure of hypertensive Sprague-Dawley (SD) rats. Graphical abstract: