Histological and immunohistochemical studies on the effects of natural honey on the acetic acid induced colitis in the albino rats

Natural honey are effective for healing of major wounds, abscesses and burn. CoIonic tissue lesions of intestinal inflammatory disease patients seem to be related to the increased local production of proinflammatory cytokines such as IL-I, IL-6 and TNF-alpha. To assess f there is any beneficial effect of honey on the acetic acid induced colitis through histological and immunohistochemical studies for TNF-alpha. Adult male albino rats [n= 60] were randomly divided into 3 main groups [preventive, 24 hr; acute induced colitis, 3 days and chronic induced colitis, 7 days,]: each group was subdivided into 4 subgroups [n=S/each,]: All subgroups were treated endoanally as follows: the first subgroup [control one,] treated with saline; the second [control 2] treated with honey; the third treated with acetic acid to induce colitis and the last subgroup treated with both acetic acid and honey. The studied rats of the different groups were sacrificed [24 hr; 3 and 7 days respectively]. Macroscopic and microscopic alterations in colonic tissue were evaluated. TNF-alpha expressions were assessed through immunohistochemistry. There were good effects of honey in all the 3 studied groups expressed by significant decrease in ulcer, mucosal and submucosal inflammatory cellular infiltrates and expression of TNF-alpha. Moreover, there was a positive correlation between the inflammatory cellular infiltrates and expression of TNF-alpha[p value < 0. 05] Honey has a role in prevention and treatment of ulcerative colitis in rats. Further studies are required to explore tile active ingredients responsible for the antioxidant effect of honey and its therapeutic potential in humans

Alteration of nitrergic neuromuscular transmission as a result of acute experimental colitis in rat

Nitric oxide (NO) is a non-adrenergic, non-cholinergic neurotransmitter found in the enteric nervous system that plays a role in a variety of enteropathies, including inflammatory bowel disease. Alteration of nitrergic neurons has been reported to be dependent on the manner by which inflammation is caused. However, this observed alteration has not been reported with acetic acid-induced colitis. Therefore, the purpose of the current study was to investigate changes in nitrergic neuromuscular transmission in experimental colitis in a rat model. Distal colitis was induced by intracolonic administration of 4% acetic acid in the rat. Animals were sacrificed at 4 h and 48 h postacetic acid treatment. Myeloperoxidase activity was significantly increased in the acetic acid-treated groups. However, the response to 60 mM KCl was not significantly different in the three groups studied. The amplitude of phasic contractions was increased by Nomega-nitro-L-arginine methyl ester (L-NAME) in the normal control group, but not in the acetic acid-treated groups. Spontaneous contractions disappeared during electrical field stimulation (EFS) in normal group. However, for the colitis groups, these contractions initially disappeared, and then reappeared during EFS. Moreover, the observed disappearance was diminished by L-NAME; this suggests that these responses were NO-mediated. In addition, the number of NADPH-diaphorase positive nerve cell bodies, in the myenteric plexus, was not altered in the distal colon; whereas the area of NADPH-diaphorase positive fibers, in the circular muscle layer, was decreased in the acetic acidtreated groups. These results suggest that NO-mediated inhibitory neural input, to the circular muscle, was decreased in the acetic acid-treated groups.

Synthesis, biological evaluation and kinetic studies of glyceride prodrugs of diclofenac.

The prodrugs (glyceride derivatives) 3a and 3b of diclofenac were prepared by reacting 1, 2, 3-trihydroxy propane-1,3-dipalmitate/stearate with the acid chloride of diclofenac as potential prodrugs to reduce the gastrointestinal toxicity associated with them. These prodrugs were evaluated for their ulcerogenicity, anti-inflammatory and analgesic activity. It was found that the prodrugs were significantly less irritating to the gastric mucosa as indicated by severity index of 0.86, 0.78 compared to 1.6 of diclofenac. The prodrugs 3a and 3b showed better anti-inflammatory and analgesic activity than the parent drugs. The hydrolysis of prodrugs 3a and 3b were studied at pH 3, 4, 5 and 7.4. The HPLC analysis showed that the prodrugs were resistant to hydrolysis at pH 3, 4 and 5 indicating that they did not hydrolyze in acidic environment, whereas at pH 7.4 the prodrugs readily released the parent drug in significant quantities. The plasma levels of diclofenac were also analyzed by HPLC in rats after single oral dose of the prodrugs. The results indicated that the parent drugs were readily released. The concentration of diclofenac during the study was found higher in animals treated with prodrugs 3a and 3b compared with animals treated with diclofenac. The concentration of diclofenac was found to be 38.59, 33.6 and 30.36 microg/ml in animals treated with prodrugs 3a, 3b and diclofenac respectively. In conclusion, all these studies indicated that the glyceride prodrugs of diclofenac might be considered as potential biolabile prodrugs of diclofenac.

Effect of Bacopa monniera and Azadirachta indica on gastric ulceration and healing in experimental NIDDM rats.

Gastric ulcers were induced in normal/NIDDM rats by various physical (2 hr cold restraint stress and 4 hr pylorus ligation) and chemical agents (ethanol, 1 ml/200 g, oral, 1 hr before; aspirin, 200 mg/kg, oral, 4 hr) and duodenal ulcers were induced by cysteamine (40 mg/200 g). Ulcer healing activity was studied in gastric ulcers induced by acetic acid (50%) and HCI (0.6 M). The result indicated that in both, normal and NIDDM rats, B. monniera extract (BME, 20-100 mg/kg) did not show any significant effect on blood glucose level, while A. indica (AIE, 250-1000 mg/kg) significantly decreased it. However, both BME (50 mg/kg) and AIE (500 mg/kg) showed significant anti-ulcer and ulcer-healing activities in normal and NIDDM rats. Further, the present results also indicated that the ulcer protective effects of BME was more pronounced in non-diabetic, while that of AIE was more in NIDDM rats. The anti-ulcer and ulcer-healing activities of BME and AIE may be due to their effects on various mucosal offensive and defensive factors, and correction of blood sugar level by AIE may help to have more ulcer protective effect in NIDDM rats.

Role of mucosal mast cells in visceral hypersensitivity in a rat model of irritable bowel syndrome

The involvement of mucosal mast cells (MMC) in the pathophysiology of irritable bowel syndrome (IBS) is still controversial. We aimed to re-evaluate the role of MMC in visceral hypersensitivity associated with IBS using a rat IBS model that develops the IBS symptom after a subsidence of acetic acid-induced colitis. No significant difference in the number of MMC was observed between normal rat colon and IBS rat colon. (61.7 +/-2.9/mm 2 in normal vs. 88.7 +/-13.3/mm 2 in IBS, p >0.29). However, the degranulation rate of MMC was significantly higher in IBS rat colon (49.5 +/-2.4% in normal vs. 68.8 +/-3.4% in IBS, p >0.05). Pretreatment of a mast cell stabilizer, doxantrazole (5 mg/kg, i.p.), reduced the degranulation rate of MMC and significantly attenuated visceral hypersensitivity to rectal distension in IBS rat, whereas it had no effect on the visceral sensory responses in normal rat. These results suggest that, although the number of MMC is not significantly changed in IBS rat colon, the higher degranulation rate of MMC is responsible for visceral hypersensitivity in this model IBS.

Evaluation of Pongamia pinnata root extract on gastric ulcers and mucosal offensive and defensive factors in rats.

Effect of methanolic extract of P. Pinnata roots (PPRM) was studied against various experimental gastric ulcer models and offensive and defensive gastric mucosal factors in rats. An initial dose-response study using 12.5-50 mg/kg P. Pinnata root extract, when given orally in two divided dose for 4 days + 5th full dose on the day of experiment 60 min before the experiment, indicated 25 mg/kg as an optimal regimen and was used for further study. PPRM showed significant protection against aspirin and 4 hr PL, but not against ethanol-induced gastric ulceration. It showed tendency to decrease acetic acid-induced ulcer after 10 days treatment. Ulcer protective effect of PPRM was due to augmentation of mucosal defensive factors like mucin secretion, life span of mucosal cells, mucosal cell glycoproteins, cell proliferation and prevention of lipid per oxidation rather than on the offensive acid-pepsin secretion.

Modulation by insulin rather than blood glucose of the pain threshold in acute physiological and flavone induced antinociception in mice.

The present study investigated the cause effect relationship between glycemic and algesic states. The hypo- and hyperglycemic conditions were induced physiologically through exercise (3 min swim at room temperature 28 degrees - 30 degrees C) and external dextrose (2 g/kg, ip) administration respectively in mice. Besides, flavone (50 mg/kg, sc) a known antinociceptive drug was chosen to study such a cause effect relationship. The anti-nociception was assessed by acetic acid assay, blood glucose measured using glucometer (Ames) and serum insulin by radioimmunoassay. The findings revealed that irrespective of the glycemic state whether hypo-, hyper, or euglycemic induced by swim stress, dextrose or flavone per se respectively, significant antinociceptive response was recorded. Pretreatment with flavone (50 mg/kg, sc) always exhibited a tendency to reverse the hyperglycemia, if any, but enhanced the antinociceptive response either after swim stress or after dextrose. These data support the contention that changes in the glycemic state in acute condition is not responsible for antinociceptive response and thereby suggesting dissociation between these two parameters. Extended studies estimating serum insulin level after the above mentioned maneuvers showed a significant rise whenever antinociceptive response was recorded irrespective of the glycemic state. It is suggested that serum insulin level, a hormonal parameter rather than the blood glucose level, which is a metabolic parameter, appears more reliable. It appears that the changes in serum insulin level produced by various treatments may have a relationship with the antinociceptive response. However, this study has the limitation that the results can apply only for acute conditions and extrapolation to clinical conditions is debatable.

Analgesic and anti-inflammatory effects of phosphodiesterase inhibitors.

The aim of the present study was to investigate the role of phosphodiesterase (PDE) enzyme inhibitors namely rolipram and theophylline in pain and inflammation in experimental animals. Rolipram, a selective PDE IV inhibitor and theophylline a nonspecific PDE inhibitor exerted dose dependent analgesic and anti-inflammatory effect against acetic acid-induced writhing in mice and carrageenan-induced paw edema in rats, respectively. Nimesulide (1, 2 mg/kg) produced significant anti-inflammatory effect. Further, nimesulide (0.5 mg/kg) potentiated analgesic effect of rolipram but it failed to modulate the anti-inflammatory effect of PDE inhibitors. Present study suggests that PDE enzymes might be playing a role in nociceptive and inflammatory responses in animals.

Diuretics physiology pharmacology and clinical use

Uricosuric diuretics have been developed to counteract renal urate retention accompanying diuretic-induced extracellular volume contraction. Their intrinsic uricosuric activity would prevent diuretic-induced hyperuricemia. Ticrynafen, a prototype uricosuric diuretic, has largely fallen into disuse because of hepatic toxicity. However, one lesson learned during the short period that ticrynafen was available in the US is that the administration of a potent uricosuric agent to a patient previously trated with diuretics can precipitate acute renal failure, possibly as a consequence of uric acid nephropathy. Another novel uricosuric diuretic, indacrinone, is composed of two enantiomorphic isomers exhibiting predominantly either a uricosuric or a natriuretic action. Manipulation of the isomer ratio currently is being attempted with a view toward obtaining a combination that produces little change in the serum urate during chronic diuretic therapy. Uricosuric diuretics have the therapeutic potential to treat hypertension and edematous states without increasing the serum urate. Although current information suggests that chronic asymptomatic hyperuricemia poses very little health hazard, future data could indicate that it may be desirable to maintain the serum urate near the normal range