Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.
Humans ; Peri-Implantitis/pathology* ; Titanium/pharmacology* ; Dental Implants/adverse effects* ; Osteolysis/pathology* ; Inflammation/chemically induced*

OBJECTIVETo observe the changes in pulmonary artery protein kinase C (PKC) activity in rats with chronic inflammatory pulmonary hypertension (PHT).

METHODSChronic inflammatory PHT was induced in rats with monocrotaline. The PKC activities in the rat pulmonary arteries were measured by radioactive assay during the development of PHT.

RESULTSWith the development of chronic inflammatory PHT, the total and cytosolic fractions of PKC activity in PHT rat pulmonary arteries increased initially with subsequent decrease (Plt;0.05), but the membranous fraction of PKC activity and the membrane-to-cytosol PKC activity ratio increased continuously (P<0.05).

CONCLUSIONThe up-regulation of PKC activity and the translocation of PKC might be associated with the development of chronic inflammatory PHT in rats.

Animals ; Chronic Disease ; Hypertension, Pulmonary ; chemically induced ; enzymology ; Inflammation ; chemically induced ; enzymology ; Male ; Monocrotaline ; Protein Kinase C ; metabolism ; Pulmonary Artery ; enzymology ; Rats ; Rats, Wistar

BACKGROUNDAn inflammatory response leading to organ dysfunction and failure continues to be a major problem after injury in many clinical conditions such as sepsis, severe burns, and trauma. It is increasingly recognized that atrial natriuretic peptide (ANP) possesses a broad range of biological activities, including effects on endothelial function and inflammation. A recent study has revealed that ANP exerts anti-inflammatory effects. In this study we tested the effects of human ANP (hANP) on lung injury in a model of oleic acid (OA)-induced acute lung injury (ALI) in rats.

METHODSRats were randomly assigned to three groups (n = 6 in each group). Rats in the control group received a 0.9% solution of NaCl (1 ml × kg(-1) × h(-1)) by continuous intravenous infusion, after 30 minutes a 0.9% solution of NaCl (1 ml/kg) was injected intravenously, and then the 0.9% NaCl infusion was restarted. Rats in the ALI group received a 0.9% NaCl solution (1 ml × kg(-1) × h(-1)) intravenous infusion, after 30 minutes OA was injected intravenously (0.1 ml/kg), and then the 0.9% NaCl infusion was restarted. Rats in the hANP-treated ALI group received a hANP (0.1 µg × kg(-1) × min(-1)) infusion, after 30 minutes OA was injected intravenously (0.1 ml/kg), and then the hANP infusion was restarted. The anti-inflammation effects of hANP were evaluated by histological examination and determination of serum cytokine levels.

RESULTSSerum interleukin (IL)-1β, IL-6, IL-10 and tumor necrosis factor (TNF) α were increased in the ALI group at six hours. The levels of all factors were significantly lower in the hANP treated rats (P < 0.005). Similarly, levels of IL-1β, IL-6, IL-10 and TNF-α were higher in the lung tissue in the ALI group at six hours. hANP treatment significantly reduced the levels of these factors in the lungs (P < 0.005). Histological examination revealed marked reduction in interstitial congestion, edema, and inflammation.

CONCLUSIONhANP can attenuate inflammation in an OA-induced lung injury in rat model.

Acute Lung Injury ; chemically induced ; drug therapy ; Animals ; Atrial Natriuretic Factor ; therapeutic use ; Disease Models, Animal ; Inflammation ; chemically induced ; drug therapy ; Male ; Oleic Acid ; toxicity ; Rats ; Rats, Wistar

BACKGROUNDExcessive iodine intake and viral infection are recognized as both critical factors associated with autoimmune thyroid diseases. Toll-like receptors (TLRs) have been reported to play an important role in autoimmune and inflammatory disorders. In this study, we aimed to clarify the possible mechanism of TLR3 involved in polyinosine-polycytidylic acid (poly(I:C)) promoting excessive iodine intake induced thyroiditis in non-obese diabetic (NOD) mice.

METHODSBoth NOD and BALB/c mice were randomly assigned to four groups: control group (n = 5), high iodine intake (HI) group (n = 7), poly(I:C) group (n = 7) and combination of excessive iodine and poly(I:C) injection (HIP) group (n = 7). After 8 weeks, mice were weighed and blood samples were collected. All the mice were sacrificed before dissection of spleen and thyroid gland. Then, thyroid histology, thyroid secreted hormone, expression of CD3(+) cells and TLR3 as well as inflammatory mRNA level were evaluated.

RESULTSBoth NOD and BALB/c mice from HI and HIP group represented goiter and increasing thyroid relative weight. Thyroid histology evidence indicated that only HIP group of NOD mice showed severe thyroiditis with lymphocytes infiltration in majority of thyroid tissue, severe damage of follicles and general fibrosis. Immunofluorescence staining results displayed a large number of CD3(+) cells in HIP NOD mice. Real-time polymerase chain reaction (PCR) results suggested interferon (IFN)-α increased over 30 folds and IFN-γ expression was doubled compared with control group, but interleukin (IL)-4 remained unchanged in HIP group of NOD mice thyroid. Meanwhile, over one third decrease of blood total thyroxine (TT4) and increased thyroid-stimulating hormone (TSH) was observed in HIP group of NOD mice. Only HIP group of NOD mice represented significantly elevation of TLR3 expression.

CONCLUSIONPoly(I:C) enhanced excessive dietary iodine induced thyroiditis in NOD mice through increasing TLR3 mediated inflammation.

Animals ; Female ; Inflammation ; chemically induced ; metabolism ; Iodine ; toxicity ; Mice ; Mice, Inbred NOD ; Poly I-C ; pharmacology ; Thyroiditis ; chemically induced ; immunology ; metabolism ; Toll-Like Receptor 3 ; metabolism

Using the latency of paw withdrawal (PWL) from a noxious thermal stimulus as a measure of hyperalgesia, the effects of i.p. injection of meptazinol and its isomers, 112824 and 112825, on carrageenan-induced thermal hyperalgesia were studied in awaked carrageenan-inflamed rats. Peripheral inflammation was induced by intraplantar (i.pl.) injection of carrageenan (2 mg/100 microl) into one hindpaw in rats. Carrageenan produced marked inflammation (edema and erythema) and thermal hyperalgesia in the injected paws, which peaked at 3 h after injection and showed little change in magnitude for another 3 h. Injection of 0.1 mg/kg meptazinol (i.p.) at 3 h after carrageenan had no effect on the PWLs of either inflamed or non-inflamed hindpaw during the next 100 min (P>0.05, n=8). At the dosage of 1 and 10 mg/kg, meptazinol produced marked anti-nociception and anti-hyperalgesia in non-inflamed and inflamed hindpaw, respectively (P<0.05, n=8-11). The prolonging effect of meptazinol on PWL in inflamed hindpaw was more potent than that in non-inflamed hindpaw. Pre-administration of 1.5 mg/kg naloxone significantly antagonized meptazinol-induced anti-nociception and anti-hyperalgesia. Intraperitoneal injection of an isomer of meptazinol, 112825 (1.5 mg/kg), but not 112824 (1 mg/kg), markedly increased the PWL of the non-inflamed hindpaw. Nevertheless, both the isomers produced similar anti-hyperalgesic effect to that of meptazinol (P<0.05, n=8), which was completely reversed by naloxone (1.5 mg/mg). The results suggest that meptazinol and its isomers have anti-nociceptive and anti-hyperalgesic properties with the former more potent. The effects are mainly mediated by mu opioid receptors. This study provides an important clue for extending clinical utilization of meptazinol and its isomers.
Analgesics, Opioid ; pharmacology ; Animals ; Carrageenan ; Hyperalgesia ; chemically induced ; physiopathology ; Inflammation ; chemically induced ; Isomerism ; Male ; Meptazinol ; pharmacology ; Nociceptors ; drug effects ; Pain ; physiopathology ; Pain Measurement ; methods ; Rats ; Rats, Sprague-Dawley

AIMTo investigate whether formalin inflammatory pain can induce hippocampal neuronal apoptosis of rats or not.

METHODSRats were subcutaneously injected with 0.2 ml 0.5% formalin into the ventral surface of right hind paw to induce periphery inflammatory pain. The flinches of rats were counted to observe their painful reaction. Flow cytometry was used to assay the ratio of apoptosis of hippocampal neurons. The immunohistochemistry was used to observe the expression of p53 protein in hippocampal subregions.

RESULTSCompared with control group, the apoptotic ratio of hippocampal neurons was significantly increased in rats with inflammatory pain, and formalin inflammatory pain induced upregulation of p53 protein expression in all hippocampal subregions. Both the apoptotic ratio and the p53 protein expression peaked on the third day after the formalin injection. The twice injection of formalin into the hind paws of rats resulted in an enhancement of painful reaction and increase in apoptotic ratio of hippocampal neurons compared with the rats of injection formalin once group.

CONCLUSIONFormalin inflammatory pain can induce the hippocampal neuronal apoptosis in rats with a certain time course. Neuronal apoptosis is relevant to the intensity of pain. The up-regulation of p53 protein expression may implicate in the induction of hippocampal neuronal apoptosis in rats with inflammatory pain.

Animals ; Apoptosis ; Formaldehyde ; Hippocampus ; pathology ; physiopathology ; Inflammation ; chemically induced ; physiopathology ; Male ; Neurons ; pathology ; Pain ; chemically induced ; physiopathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tumor Suppressor Protein p53 ; metabolism

The aim of the present study is to evaluate the ability and mechanism by which grape seed procyanidin extract (GSPE) relieves arsenic trioxide (As2O3)-induced renal inflammatory injury. Therefore, male Kunming mice were treated with As2O3 and/or GSPE by gavage for 5 weeks. Mice were then sacrificed and inflammatory cytokines of kidneys were examined by ELISA, whereas the expression levels of molecules involved in the nuclear factor (NF)-κB signaling pathway were evaluated by both qRT-PCR and Western blot. Our results indicate that GSPE prevents As2O3-mediated renal inflammatory injury by inhibiting activation of the NF-κB signaling pathway and inflammatory cytokine production, while promoting expression of anti-inflammatory cytokines.
Animals ; Arsenic ; toxicity ; Grape Seed Extract ; therapeutic use ; Inflammation ; chemically induced ; drug therapy ; Kidney Diseases ; chemically induced ; drug therapy ; Male ; Mice ; Proanthocyanidins ; therapeutic use

AIMTo observe the changes of nitric oxide synthase (NOS) activity and nitric oxide (NO) content of hippocampus including their time course and region distribution character in rat during the process of formalin-induced inflammatory pain as well as the pain behavior of rat.

METHODSThe pain threshold (PT) was determined by radiant heat-induced tail flick test. NOS expression in the hippocampus was determined by using NADPH-d histochemical staining. NO production in hippocampus was determined by assaying NO3- and NO2-.

RESULTSSubcutaneous injection of formalin elicited nociceptive behavioural response and led to decrease in PT of rat. The number and staining degree of NADPH-d positive neurons began to increase at 6 h after the formalin injection in CA1, CA2 - 3 and DG of hippocampus as well as NO content, which increased most obviously at 12 h and returned to control level at 48 h.

CONCLUSIONFormalin-induced inflammatory pain could induce the elevation of NOS activity in CA1, CA2 - 3 and DG of hippocampus with a certain time course, which further led to a increase of NO production in hippocampus.

Animals ; Formaldehyde ; adverse effects ; Hippocampus ; metabolism ; Inflammation ; chemically induced ; metabolism ; Male ; Nitric Oxide ; biosynthesis ; Nitric Oxide Synthase ; metabolism ; Pain ; chemically induced ; metabolism ; Pain Threshold ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To observe the relation between the expression of CTNNAL1 and the airway resistance in rats with airway hyperresponsiveness. METHODS: Thirty Wister rats were randomly divided into 5 groups: a normal control group, a 2 d ozone attack group, a 4 d ozone attack group, a 6 d ozone attack group, and a 6 d ozone attack+2 d dexamethasone treatment group (6 rats in each group). The distribution of CTNNAL1 was observed by in situ hybridization; the expression of CTNNAL1 was detected by fluorescence quantitative RT-PCR; the airway resistance was detected in by Buxco pulmonary function analysis system; and the relevance of the expression of CTNNAL1 and the resistance of respiratory tract in rat with airway hyperresponsiveness were analyzed. RESULTS: CTNNAL1 was distributed in bronchial epithelial cells, goblet cells, endothelial cells, and the alveolar wall. With the increase of the ozone attack, the expression of CTNNAL1 mRNA gradually reduced, the airway hyperresponsiveness was aggravated, and the airway resistance was increased. CONCLUSION During airway hyperresponse, the reduction of CTNNAL1 mRNA can increase the airway resistance. There is a negative correlation between the reduction of CTNNAL1 mRNA and the airway hyperresponsiveness. CTNNAL1 is an adhesion molecule related to airway hyperresponsiveness susceptibility.
Airway Resistance ; Animals ; Bronchial Hyperreactivity ; chemically induced ; metabolism ; physiopathology ; Female ; Inflammation ; chemically induced ; physiopathology ; Male ; Ozone ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; alpha Catenin ; genetics ; metabolism

OBJECTIVETo investigate the changes in the levels of monocarboxylate transporter-2 in spinal cord horn in a rat model of chronic inflammatory pain.

METHODSMale SD rats weighting 180 - 220 g were randomly divided into two groups(n = 48): normal saline group (NS group), complete Freund's adjuvant group (CFA group). Rats were given injections of CFA 100 µl in left hind paw in group CFA, and an equal volume of saline was given injection in group NS. Mechanical withdraw threshold(MWT) and thermal withdraw latency(TWL) were measured at before injection(T0 and 3 h, 1 d, 3 d, 7 d, 14 d, and 21 d after injection(T1-7). Four rats were chosen from each group at T0-7 and sacrificed, and L4-5 segments of the spinal cord horn were removed for measurement of the expression of monocarboxylate transporter-2 by Western blot analysis.

RESULTSIn CFA group, mechanical hyperalgesia and allodynia appeared on the 3 h after CFA injection, then until the day 14. The expression of monocarboxylate transporter-2 in the spinal dorsal horn of rats in CFA group was significantly higher than that in normal control group at T1-6(P <0.05). The protein level of monocarboxylate transporter-2 was apparently correlated with MWT and TWL(P <0.01 and P <0.05) in CFA group.

CONCLUSIONThe level of monocarboxylate transporter-2 in spinal dorsal horn is significantly increased in a rat model of chronic inflammatory pain and the change may involve in the formation and maintenance of central sensitization in spinal cord of chronic inflammatory uain.

Animals ; Disease Models, Animal ; Freund's Adjuvant ; Hyperalgesia ; chemically induced ; Inflammation ; chemically induced ; metabolism ; Male ; Monocarboxylic Acid Transporters ; metabolism ; Pain ; chemically induced ; metabolism ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; metabolism ; physiopathology