Roberto César Pereira Lima Júnior

Effect of different doses of zoledronic acid in establishing of bisphosphonate-related osteonecrosis

OBJECTIVES To establish osteonecrosis of the jaws in rats treated with different doses of zoledronic acid (ZA). METHODS Male Wistar rats (n=6-7) received three consecutive weekly intravenous ZA infusions at doses of 0.04, 0.20 or 1.00mg/kg ZA or saline (control). Four weeks after the last administration, the animals were submitted to simple extraction of the lower left first molar. An additional dose of ZA was administered seven days later, and the animals were sacrificed 28 days after exodontia. Weight was measured and blood was collected weekly for analysis. The jaw was radiographically and microscopically examined along with the liver, spleen, kidney and stomach. RESULTS All ZA doses showed a higher radiolucent area than the control (p<0.0001), but the dose of 0.04mg/kg did not show BRONJ. Doses of 0.20 and 1.00mg/kg ZA showed histological evidence of bone necrosis (p=0.0004). Anaemia (p<0.0001, r(2)=0.8073) and leucocytosis (p<0.0001, r(2)=0.9699) are seen with an increase of lymphocytes (p<0.0001, r(2)=0.6431) and neutrophils and monocytes (p=0.0218, r(2)=0.8724) in all the animals treated with an increasing dose of ZA. Haemorrhage and ectasia were observed in the spleen (p=0.0004) and stomach (p=0.0168) in a dose-dependent manner, and the animals treated with ZA showed a lower rate of weight gain (p<0.0001). CONCLUSIONS We designed a bisphosphonate-related osteonecrosis of the jaw model that reproduces radiographic and histological parameters and mimics clinical alterations such as leucocytosis, anaemia and idiosyncratic inflammatory post infusion reactions.

Gastroprotective potential of frutalin, a d-galactose binding lectin, against ethanol-induced gastric lesions

The present study was designed to verify whether frutalin (FTL) affords gastroprotection against the ethanol-induced gastric damage and to examine the underlying mechanism(s). Gastric damage was induced by intragastric administration of 0.2 ml of ethanol (96%). Mice in groups were pretreated with FTL (0.25, 0.5 and 1 mg/kg; i.p.), cimetidine (100 mg/kg; p.o.), or vehicle (0.9% of NaCl, 10 mL/kg; p.o.), 30 min before ethanol administration. They were sacrificed 30 min later, the stomachs excised, and the mucosal lesion area (mm²) measured by planimetry. Gastroprotection was assessed in relation to inhibition of gastric lesion area. To study the gastroprotective mechanism(s), its relations to capsaicin-sensitive fibers, endogenous prostaglandins, nitric oxide, sulphydryls, ATP-sensitive potassium channels, adrenoceptors, opioid receptors and calcium channels were analyzed. Treatments effects on ethanol-associated oxidative stress markers GSH and MDA were measured in gastric tissue. FTL afforded a dose-unrelated gastroprotection against the ethanol damage. However, it failed to prevent the ethanol-induced changes in the levels of GSH and MDA. It was observed that the gastroprotection by FTL was greatly reduced in animals pretreated with capsazepine, indomethacin, L-NAME or glibenclamide. Considering the results, it is suggested that the FTL could probably be a good therapeutic agent for the development of new medicine for the treatment of gastric ulcer.

Electroacupuncture ameliorates experimental colitis induced by TNBS through activation of interleukin-10 and inhibition of iNOS in mice

PURPOSE To study the anti-inflammatory actions of electroacupuncture (EAc) on an experimental colitis model in mice. METHODS Thirty-eight male Swiss mice, divided in five groups, were subjected to induction of colitis by TNBS in 50% ethanol. Saline (SAL) and ethanol (ETNL) groups served as controls. TNBS+EAc and TNBS+ dexamethasone subgroups were treated with EAc 100Hz and dexamethasone (DEXA) 1 mg/Kg/day, respectively. After three days, a colon segment was obtained for quantification of myeloperoxidase (MPO) activity, immunohistochemistry for iNOS, malondialdehyde (MDA) and cytokines (IL-1β and IL-10). RESULTS Neutrophilic activity, assayed as MPO activity, was significantly higher in the TNBS colitis group than that in the saline control group. TNBS+EAc group showed suppression of IL-10 in the colon. EAc treatment significantly reduced the concentration of MDA and the expression of iNOS, as compared to the other groups. CONCLUSION Electroacupuncture 100Hz applied to acupoint ST-36 promotes an anti-inflammatory action on the TNBS-induced colitis, mediated by increase of IL-10 and decrease of iNOS expression.

Progressive loss of E-cadherin immunoexpression during cervical carcinogenesis

PURPOSE To investigate E-cadherin immunoexpression during cervical carcinogenesis. METHODS We assessed the immunohistochemical expression of E-cadherin in squamous intraepithelial lesions (SIL - 52 cases), squamous cell carcinoma (SCC) of the uterine cervix (23 cases) and also in eight cases of cervicitis. RESULTS The results show very different E-cadherin membrane expression levels when cervicitis (88%), SILs (73%) and SCC (17%) were compared. In SILs, higher E-cadherin loss was seen in less differentiated cells in the basal third of the epithelium. This study suggests that the absence of E-cadherin expression in the membrane is a molecular event that is observed more often in SCC of the uterine cervix than in SILs or cervicitis. CONCLUSIONS E-cadherin is an essential molecule during the process of cervical carcinogenesis and in this context exhibits a different expression pattern according to the epithelial thickness layer.

Involvement of Nitric Oxide on Bothropoides insularis Venom Biological Effects on Murine Macrophages In Vitro

Viperidae venom has several local and systemic effects, such as pain, edema, inflammation, kidney failure and coagulopathy. Additionally, bothropic venom and its isolated components directly interfere on cellular metabolism, causing alterations such as cell death and proliferation. Inflammatory cells are particularly involved in pathological envenomation mechanisms due to their capacity of releasing many mediators, such as nitric oxide (NO). NO has many effects on cell viability and it is associated to the development of inflammation and tissue damage caused by Bothrops and Bothropoides venom. Bothropoides insularis is a snake found only in Queimada Grande Island, which has markedly toxic venom. Thus, the aim of this work was to evaluate the biological effects of Bothropoides insularis venom (BiV) on RAW 264.7 cells and assess NO involvement. The venom was submitted to colorimetric assays to identify the presence of some enzymatic components. We observed that BiV induced H2O2 production and showed proteolytic and phospholipasic activities. RAW 264.7 murine macrophages were incubated with different concentrations of BiV and then cell viability was assessed by MTT reduction assay after 2, 6, 12 and 24 hours of incubation. A time- and concentration-dependent effect was observed, with a tendency to cell proliferation at lower BiV concentrations and cell death at higher concentrations. The cytotoxic effect was confirmed after lactate dehydrogenase (LDH) measurement in the supernatant from the experimental groups. Flow cytometry analyses revealed that necrosis is the main cell death pathway caused by BiV. Also, BiV induced NO release. The inhibition of both proliferative and cytotoxic effects with L-NAME were demonstrated, indicating that NO is important for these effects. Finally, BiV induced an increase in iNOS expression. Altogether, these results demonstrate that B. insularis venom have proliferative and cytotoxic effects on macrophages, with necrosis participation. We also suggest that BiV acts by inducing iNOS expression and causing NO release.

Bases da Resposta Inflamatória do Trato Gastrintestinal

A inflamacao e uma resposta vascular, celular e humoral, responsavel pelo processo de defesa dos organismos vivos ante agentes agressores. Essa resposta fisiologica e resultante da acao coordenada entre o sistema imunologico e o tecido no qual ocorreu a lesao. Por incorporar varios mecanismos biologicos, como a formacao de edema, fagocitose, angiogenese, fibroplasia, liberacao de mediadores quimicos, alem de outros fatores, a inflamacao passou a ser entendida como um processo, proveniente de uma soma de eventos, que, de acordo com o tempo de evolucao e as caracteristicas patologicas envolvidas, pode ser classificada em in - flamacao aguda ou cronica (KUMAR, 2010)