Therapeutic and prophylactic thalidomide in TNBS-induced colitis: Synergistic effects on TNF-α, IL-12 and VEGF production

AIM: To evaluated the therapeutic and prophylactic effect of thalidomide on 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Thalidomide has been reported to downregulate the expression of tumor necrosis factor a (TNF-α), IL-12, and vascular endothelial growth factor (VEGF), hallmarks of intestinal inflammation in Crohn's disease (CD). METHODS: Male Wistar rats were divided in five groups of ten animals each. Four groups received a rectal infusion of TNBS in ethanol. The first group was sacrificed 7 d after colitis induction. The second and third groups received either thalidomide or placebo by gavage and were sacrificed at 14 d. The fourth group received thalidomide 6 h before TNBS administration, and was sacrificed 7 d after induction. The fifth group acted as the control group and colitis was not induced. Histological inflammatory scores of the colon were performed and lamina propria CD4+ T cells, macrophages, and VEGF+ cells were detected by immunohistochemistry. TNF-a and IL-12 were quantified in the supernatant of organ cultures by ELISA. RESULTS: Significant reduction in the inflammatory score and in the percentage of VEGF+ cells was observed in the group treated with thalidomide compared with animals not treated with thalidomide. Both TNF-αand IL-12 levels were significantly reduced among TNBS induced colitis animals treated with thalidomide compared with animals that did not receive thalidomide. TNF-αlevels were also significantly reduced among the animals receiving thalidomide prophylaxis compared with untreated animals with TNBS-induced colitis. Intestinal levels of TNF-αand IL-12 were significantly correlated with the inflammatory score and the number of VEGF+ cells. CONCLUSION: Thalidomide significantly attenuates TNBS-induced colitis by inhibiting the intestinal production of TNF-α, IL-12, and VEGF. This effect may support the use of thalidomide as an alternate approach in selected patients with CD.

Toxoplasma gondii causes death and plastic alteration in the jejunal myenteric plexus

AIM:To assess the effects of ME-49 Toxoplasma gondii(T.gondii) strain infection on the myenteric plexus and external muscle of the jejunum in rats.METHODS:Thirty rats were distributed into two groups:the control group(CG)(n = 15) received 1 m L of saline solution orally, and the infected group(IG)(n=15)inoculated with 1 m L of saline solution containing500 oocysts of M-49 T.gondii strain orally.After 36 d of infection,the rats were euthanized.Infection with T.gondii was confirmed by blood samples collected from all rats at the beginning and end of the experiment.The jejunum of five animals was removed and submitted to routine histological processing(paraffin)for analysis of external muscle thickness.The remaining jejunum from the others animals was used to analyze the general population and the NADH-diaphorase,VIPergic and nitrergic subpopulations of myenteric neurons;and the enteric glial cells(S100-IR).RESULTS:Serological analysis showed that animals from the IG were infected with the parasite.Hypertrophy affecting jejunal muscle thickness was observed in the IG rats(77.02±42.71)in relation to the CG(51.40±12.34),P<0.05.In addition,31.2%of the total number of myenteric neurons died(CG:39839.3±5362.3;IG:26766.6±2177.6;P<0.05);hyperplasia of nitrergic myenteric neurons was observed(CG:7959.0±1290.4;IG:10893.0±1156.3;P<0.05);general hypertrophy of the cell body in the remaining myenteric neurons was noted[CG:232.5(187.2-286.0);IG:248.2(204.4-293.0);P<0.05];hypertrophy of the smallest varicosities containing VIP neurotransmitter was seen(CG:0.46±0.10;IG:0.80±0.16;P<0.05)and a reduction of 25.3%in enteric glia cells(CG:12.64±1.27;IG:10.09±2.10;P<0.05)was observed in the infected rats.CONCLUSION:It was concluded that infection with oocysts of ME-49 T.gondii strain caused quantitative and plastic alterations in the myenteric plexus of the jejunum in rats.

Distinct patterns of mucosal apoptosis in H pylori-associated gastric ulcer are associated with altered FasL and perforin cytotoxic pathways

AIM: To analyze the level of apoptosis in different mucosal compartments and the differential expression of Fas/Fas-ligand and perforin in H pylori-associated gastric ulcer. METHODS: Antral specimens from patients with H pylori-related active gastric ulcer (GU), H pylori-related gastritis, and non-infected controls were analysed for densities and distribution of apoptotic cells determined by the TdT-mediated dUDP-biotin nick-end-labelling method. GU patients were submitted to eradication therapy with follow-up biopsy after 60 d. Fas, FasL, and perforin-expressing cells were assessed by immunoper- oxidase, and with anti-CD3, anti-CD20 and anti-CD68 by double immunofluorescence and confocal microscopy. Quantitative analysis was performed using a computer- assisted image analyser. RESULTS: H pylori-infected antrum showed greater surface epithelial apoptosis which decreased after eradi- cation therapy. In the lamina propria, higher rates of mononuclear cell apoptosis were observed in H pylori- gastritis. Co-expression of Fas with T-cell and macro- phage markers was reduced in GU. FasL- and perforin-expressing cells were increased in H pylori-infection and correlated with epithelial apoptosis. Perforin-expressing cells were also increased in GU compared with H pylori- gastritis. CONCLUSION: Epithelial apoptosis is increased in H pylori-infection and correlates to FasL- and perforin- expression by T cells. Expression of perforin is correlated with the tissue damage, and may represent the enhance- ment of a distinct cytotoxic pathway in GU. Increased expression of FasL not paralleled by Fas on T-cells and macrophages may indicate a reduced susceptibility to the Fas/FasL-mediated apoptosis of lymphoid cells in H pylori-infection.