Probing the chemoprevention potential of the antidepressant fluoxetine combined with epigallocatechin gallate or kaempferol in rats with induced early stage colon carcinogenesis.

The enhanced chemopreventive action against 1,2 Dimethylhydrazine (DMH)-induced preneoplastic lesion in rats could be achieved via simultaneous administration of the antidepressant fluoxetine (FLX) with two natural polyphenolic compounds viz., kaempferol (KMP) and/or epigallocatechin-gallate (EGCG). The obtained results revealed that single FLX pre-treatment possess a significant apoptotic effect by increasing the activity of serum and colon tissue caspase 3. It also attenuated the DMH driven increase in, colon tissue MDA, NO, PCNA and COX-2 expression as well as serum and colon tissue ß-catenin, with a decrease in the multiplicity of ACF and number of MPLs. The combination of FLX with either KMP or EGCG improved the antioxidant, anti-inflammatory and antiproliferating activities but with higher apoptotic activity in case of KMP. Eventually, histopathological assessment of colon tissues exposed that while sole pre-treatment can improve DMH-induced hyperplasia with only moderate inflammatory infiltration, tissues from the combined pre-treatment regimens groups exhibited almost a normal colonic architecture with slight submucosal edema. The study proved that single FLX administration prior to DMH exerts a chemopreventive effect and that the investigated combined pre-treatment regimens demonstrated more potent chemopreventive and antiproliferative actions.

[Results of study concerning possible influence of rocket space activities on public health].

Using special medical examination results and specified criteria of objective evaluation, the authors summarized results of studies concerning health state of population dwelling in area possibly influenced by rocket space activities factors.

[Effects of Coptis chinensis and Evodia rutaecarpa water extract on DMH-induced precancerous lesion of colon].

OBJECTIVE: To investigate the effects of Coptis chinensis and Evodia rutaecarpa water extract on precancerous lesion of colon induced by DMH and proliferation and apoptosis changes of colon mucosa crypts. METHOD: Precancerous lesion of colon was induced by DMH. The changes of proliferation and apoptosis of colon mucosa crypts were detected by morphological analysis. The numbers of aberrant crypt foci (ACF) were measured by feulgen staining. RESULT: C. chinensis and E. rutaecarpa water extract could significantly inhibit the formation of ACF in model animals. The proliferative crypts were increased obviously in middle and distal colon, and decreased by C. chinensis and E. rutaecarpa water extract. The apoptosis crypts were increased in distal colon but not middle colon. C. chinensis and E. rutaecarpa water extract could promote apoptosis of both middle and distal colon. CONCLUSION: C. chinensis and E. rutaecarpa water extract could significantly inhibit the formation of ACF in model animals. These results indicated that C. chinensis and E. rutaecarpa water extract maybe have an inhibitory and clinically therapeutic effect on colon cancer, which were partly resulted from inhibiting proliferation and promoting apoptosis of crypts in middle and distal colon.

Suppression of colonic aberrant crypt foci by soy isoflavones is dose-independent in dimethylhydrazine-treated rats.

The potential of soy isoflavones (SIs) to reduce colon cancer has been investigated in animal models. These studies have found that outcomes are variable and depend on SI dose. The present study investigated dose-response effects of SIs on colon carcinogenesis in a chemically induced rat cancer model. Sprague-Dawley male rats were injected with 1,2-dimethylhydrazine (DMH) and were provided experimental diets that contained 0, 10, 50, 150, or 500 mg of SI aglycones/kg of diet for 12 weeks. Plasma concentrations of genistein, daidzein, and equol were determined using time-resolved fluoroimmunoassay. Plasma concentrations of these SIs tended to increase in a dose-dependent manner in DMH-treated rats. The numbers of aberrant crypt foci (ACF) and the expression of cyclooxygenase-2 (COX-2) proteins of colons were significantly decreased in the SI-fed groups compared with the control group; however, suppression was not dose-dependent. Furthermore, there were no significant correlations between plasma SI concentrations and ACF or COX-2 expression. Increased SI intake and increased plasma levels of SIs and metabolites were not associated with tissue levels of lipid peroxidation. We conclude that dietary supplementation of SIs suppresses DMH-induced ACF formation and COX-2 expression in a dose-independent manner.

Calcium inhibits colon carcinogenesis in an experimental model in the rat.

Different dietary factors can affect colorectal cancer incidence. However, the effect of increased levels of dietary calcium on neoplasms is unclear. The present study was designed to examine the effect of a low calcium supplement on experimental colon carcinogenesis induced by parenteral administration of dimethylhydrazine (DMH). One hundred and twenty 10-week-old Sprague-Dawley rats were divided into five groups of equal sex distribution. The 10 rats in group A (control group) received no treatment; the 30 rats in group B (DMH group) were injected subcutaneously with 18 weekly doses of 21 mg/kg DMH; the 20 rats in group C (EDTA control group) received EDTA solution only; the 30 rats in group D (calcium group) received calcium at 3.2 g/l by adding calcium lactate to the drinking water from the start until the conclusion of the experiment; and the 30 rats in group E (DMH + calcium group) received oral calcium supplements at the same dose as the rats in group D (calcium group) and the same DMH injections as the rats in group B (DMH group). The rats were sacrificed at 25-34 weeks. In group E, we observed a significant diminution in the number of tumours (P = 0.01); an increase in the number of tumour-free animals (P = 0.006); a change in tumour location towards the distal colon (P < 0.025); more adenomas (P = 0.02); and a diminution of adenocarcinomas and mucinous carcinomas, although this was not significant. We conclude that a low dietary calcium supplement in rats inhibits colon cancer carcinogenesis induced by DMH, and changes tumour location towards the distal colon.

Experimental colitis as a promoter in large-bowel tumorigenesis.

To study the effect of acetic acid colitis on 1,2-dimethylhydrazine-induced colon tumorigenesis, fischer 344 male rats, 10 weeks of age, were divided into three groups: one receiving 5% acetic acid enema (subgroup 1a); one receiving 10% acetic acid enema (subgroup 1b); and one not receiving acetic acid enema (group 2). Colitis developed in rats in groups 1a and 1b, resulting in early death in some cases. Rats of all three groups received the same subcutaneous dose of dimethylhydrazine given once a week for 20 weeks starting at 11 weeks of age; they were killed at 31 weeks after the first dimethylhydrazine injection. The percentage of animals having tumors in the large bowel was greatest in subgroup 1b and least in group 2. The mean number of large-bowel tumors per animal in which large-bowel had developed was determined in each group. The mean number of subgroup 1 was greater than that of group 2 and also greater than that of groups 1a and 2 combined. The results of the study suggest that colonic mucosal injury may render the colonic epithelium susceptible to tumor induction by carcinogens in the fecal stream.