Super Activated Platelet Lysate, a Novel Autologous Platelet Lysate, Regulates the Expression of Inflammasome and Cytokine in the Experimental Periodontitis in Rats

Effects of the DL76 Antagonist/Inverse Agonist of Histamine H3 Receptors on Experimental Periodontitis in Rats: Morphological Studies

BACKGROUND

Periodontitis preceded by gingivitis is the most common form of periodontal disease and occurs due to the interaction of microorganisms present in the complex bacterial aggregates of dental plaque biofilm and their metabolism products with periodontal tissues. Histamine is a heterocyclic biogenic amine acting via four types of receptors. Histamine H3 receptors act as presynaptic auto/heteroreceptors to regulate the release of histamine and other neurotransmitters.

AIM

Since the nervous system is able to regulate the progression of the inflammatory process and bone metabolism, the aim of this study was to investigate the effects of DL76, which acts as an antagonist/inverse agonist of H3 receptors, on the course of experimental periodontitis.

MATERIALS AND METHODS

This study was conducted in 24 mature male Wistar rats weighing 245-360 g, aged 6-8 weeks. A silk ligature was placed on the second maxillary molar of the right maxilla under general anesthesia. From the day of ligating, DL76 and 0.9% NaCl solutions were administered subcutaneously for 28 days in the experimental and control groups, respectively. After the experiment, histopathological, immunohistochemical and radiological examinations were performed.

RESULTS

Ligation led to the development of the inflammatory process with lymphocytic infiltration, increased epithelial RANKL and OPG expression as well as bone resorption. DL76 evoked a reduction in (1) lymphocytic infiltration, (2) RANKL and OPG expression as well as (3) bone resorption since the medians of the mesial and distal interdental spaces in the molars with induced periodontitis were 3.56-fold and 10-fold lower compared to the corresponding values in saline-treated animals with periodontitis.

CONCLUSION

DL76 is able to inhibit the progression of experimental periodontitis in rats, as demonstrated by a reduction in the inflammatory cell infiltration, a decrease in the RANKL/RANK OPG pathway expression and a reduction in the alveolar bone resorption.

Effects of AIM2 and IFI16 on Infectious Diseases and Inflammation

Both absent in melanoma 2 (AIM2) and interferon-inducible protein 16 (IFI16) are intracellular innate immune receptors that recognize double-stranded DNA released during pathogenic infection, leading to the assembly of the inflammasome. The assembly of the inflammasome results in the secretion of bioactive interleukin (IL)-1β and IL-18 and induces cell death through an inflammatory process called pyroptosis. Although the AIM2 inflammasome is generally harmful in the context of some aseptic inflammatory illnesses, it plays a protective role in infectious diseases. During inflammatory processes, there is competition between IFI16 and AIM2. In this review, we explore the impacts of IFI16 and AIM2 in infectious disease and aseptic inflammation, respectively, and how they compete.

Effect of super activated platelet lysate on cell proliferation, repair and osteogenesis

BACKGROUND

Platelet lysate (PL) is considered as an alternative to fetal bovine serum (FBS) and facilitates the proliferation and differentiation of mesenchymal cells.

OBJECTIVE

The aim of this study is to explore whether super activated platelet lysate (sPL), a novel autologous platelet lysate, has the ability to inhibit inflammation and promote cell proliferation, repair and osteogenesis as a culture medium.

METHODS

Different concentrations of sPL on human fetal osteoblastic 1.19 cell line (hFOB1.19) proliferation and apoptotic repair were investigated; And detected proliferative capacity, inflammatory factor expressions and osteogenic differentiation of human dental pulp cells (hDPCs) stimulated by LPS under 10% FBS and 5% sPL mediums.

RESULTS

sPL promoted hFOB1.19 proliferation and had repairing effects on apoptotic cells. No significant difference in proliferation and IL-1α, IL-6 and TNF-α expressions of hDPCs in FBS and sPL medium stimulated by LPS. hDPCs in sPL osteogenic medium had higher osteogenic-related factor expressions and ALP activity. LPS promoted osteogenic-related factor expressions and ALP activity of hDPCs in FBS osteogenic medium, but opposite effect showed in sPL medium.

CONCLUSION

sPL promoted osteoblast proliferation and had restorative effects. Under LPS stimulation, sPL did not promote hDPCs proliferation or inhibit inflammation. sPL promotes osteogenic differentiation of hDPCs.

Effects of Super-Activated Platelet Lysate on Early Healing of Tooth Extraction Sockets in Rats

Purpose

To evaluate the effect of super-activated platelet lysate (sPL) on wound healing of tooth extraction sockets in rats.

Methods

Rat models of the tooth extraction socket were established. Thirty-six rats were divided into control and sPL groups and sacrificed on days 7, 14, and 28 after tooth extraction. Bone formation in tooth extraction sockets were observed by microscopic computed tomography (micro-CT) and hematoxylin and eosin (HE) staining; osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), interleukin 6(IL-6), and tumor necrosis factor-alpha (TNF-α) proteins were detected by immunohistochemistry; and chemokine and osteogenic gene expressions were detected by polymerase chain reaction (PCR).

Results

sPL accelerated soft tissue wound healing in the extraction socket of rats. Micro-CT showed that the amount of bone formation and bone volume fraction were higher in the sPL group than the control 14 days after extraction. HE staining showed promotion of the formation of bony trabeculae by sPL in the apical third of the extraction socket 7 days after extraction and more mature and organized bony trabeculae in the sPL group than the control 14 days after extraction; mature bony trabeculae filling most of the fossa with lesser bone porosity in the socket in the sPL group than the control 28 days after extraction. Immunohistochemistry showed that sPL induced OPG expressions 7 and 14 days after tooth extraction but did not affect the RANKL expression while transiently promoting the IL-6 expression 7 days after extraction. PCR showed that sPL promoted chemokine expressions 7 and 14 days after extraction. The expressions of osteogenesis-related factors were higher in the sPL group than the control 7 and 28 days after extraction, while the opposite trend was observed 14 days after extraction.

Conclusion

sPL has a transient pro-inflammatory effect and promotes soft tissue healing and bone formation during early wound healing of extraction sockets in rats.

Interaction of periodontitis and orthodontic tooth movement-an in vitro and in vivo study

OBJECTIVES

The aim of this in vitro and in vivo study was to investigate the interaction of periodontitis and orthodontic tooth movement on interleukin (IL)-6 and C-X-C motif chemokine 2 (CXCL2).

MATERIALS AND METHODS

The effect of periodontitis and/or orthodontic tooth movement (OTM) on alveolar bone and gingival IL-6 and CXCL2 expressions was studied in rats by histology and RT-PCR, respectively. The animals were assigned to four groups (control, periodontitis, OTM, and combination of periodontitis and OTM). The IL-6 and CXCL2 levels were also studied in human gingival biopsies from periodontally healthy and periodontitis subjects by RT-PCR and immunohistochemistry. Additionally, the synthesis of IL-6 and CXCL2 in response to the periodontopathogen Fusobacterium nucleatum and/or mechanical strain was studied in periodontal fibroblasts by RT-PCR and ELISA.

RESULTS

Periodontitis caused an increase in gingival levels of IL-6 and CXCL2 in the animal model. Moreover, orthodontic tooth movement further enhanced the bacteria-induced periodontal destruction and gingival IL-6 gene expression. Elevated IL-6 and CXCL2 gingival levels were also found in human periodontitis. Furthermore, mechanical strain increased the stimulatory effect of F. nucleatum on IL-6 protein in vitro.

CONCLUSIONS

Our study suggests that orthodontic tooth movement can enhance bacteria-induced periodontal inflammation and thus destruction and that IL-6 may play a pivotal role in this process.

CLINICAL RELEVANCE

Orthodontic tooth movement should only be performed after periodontal therapy. In case of periodontitis relapse, orthodontic therapy should be suspended until the periodontal inflammation has been successfully treated and thus the periodontal disease is controlled again.