Sodium butyrate does not decrease the evolution of precancerous lesions in rats

Role of short-chain fatty acids in colonic inflammation, carcinogenesis, and mucosal protection and healing

Short-chain fatty acids (SCFAs), mainly acetate, propionate, and butyrate, produced by microbial fermentation of undigested food substances are believed to play a beneficial role in human gut health. Short-chain fatty acids influence colonic health through various mechanisms. In vitro and ex vivo studies show that SCFAs have anti-inflammatory and anticarcinogenic effects, play an important role in maintaining metabolic homeostasis in colonocytes, and protect colonocytes from external harm. Animal studies have found substantial positive effects of SCFAs or dietary fiber on colonic disease, but convincing evidence in humans is lacking. Most human intervention trials have been conducted in the context of inflammatory bowel disease. Only a limited number of those trials are of high quality, showing little or no favorable effect of SCFA treatment over placebo. Opportunities for future research include exploring the use of combination therapies with anti-inflammatory drugs, prebiotics, or probiotics; the use of prodrugs in the setting of carcinogenesis; or the direct application of SCFAs to improve mucosal healing after colonic surgery.

Use of defatted flaxseed meal reduces precancerous colon lesions in C57BL/6 mice

PURPOSE

To investigate the hemopreventive effect of defatted flaxseed meal in C57BL/6 mice after induction of precancerous colon lesions with 1.2-dimethylhydrazine (DMH).

METHODS

Thirty-six 12-week-old C57BL/6 mice were divided into three treatment groups(n=12 in each group): (1) diet with 10% defatted flaxseed meal; (2) diet with defatted flaxseed meal and precancerous colon lesions induced by DMH; and (3) precancerous colon lesions induced by DMH, without defatted flaxseed meal. The incidence of aberrant crypt foci (ACF), oxidative processes, expression of tumor suppressor proteins and cyclins, as well as the profile of short-chain fatty acids (SCFA) in animal feces were investigated in the presence and absence of DMH.

RESULTS

The rats consuming defatted flaxseed meals showed lesions with lower multiplicity and a reduced incidence of lesions. No changes in the expression of tumor suppressor proteins and those involved in cell cycle control were detected.

CONCLUSION

Defatted flaxseed meal protected the distal colon of mice from precancerous lesions.

Butyrate: implications for intestinal function

PURPOSE OF REVIEW

Butyrate is physiologically produced by the microbial fermentation of dietary fibers and plays a plurifunctional role in intestinal cells. This review examines the recent findings regarding the role and mechanisms by which butyrate regulates intestinal metabolism and discusses how these findings could improve the treatment of several gastrointestinal disorders.

RECENT FINDINGS

Butyrate is more than a primary nutrient that provides energy to colonocytes and acts as a cellular mediator in those cells through several mechanisms. One remarkable property of butyrate is its ability to inhibit histone deacetylases, which is associated with the direct effects of butyrate and results in gene regulation, immune modulation, cancer suppression, cell differentiation, intestinal barrier regulation, oxidative stress reduction, diarrhea control, visceral sensitivity and intestinal motility modulation. All of these actions make butyrate an important factor for the maintenance of gut health.

SUMMARY

From studies published over 30 years, there is no doubt of the important role that butyrate plays in maintaining intestinal homeostasis. However, despite these effects, clinical studies are still required to validate the routine use of butyrate in clinical practice and, specifically, in the treatment of intestinal diseases.

Effect of sodium butyrate on DMH-induced small intestinal and large intestinal tumors in rats

AIM: To investigate whether 1,2-dimethylhydrazine (DMH) can induce small intestinal tumors in rats and to examine the effect of sodium butyrate on DMH-induced small intestinal and large intestinal tumors.

METHODS: Eighty male Wistar rats were randomly divided into four groups: DMH group, DMH + NaBt group, NaBt group, and control group. After 30-32 weeks, rats were euthanized with an overdose of intravenous pentobarbital (200 mg/kg). After laparotomy, the small intestine and large intestine were dissected. The location, number, shape and size of intestinal tumors were examined and recorded. All tissues were subjected to hematoxylin and eosin (H&E) staining to observe histological changes.

RESULTS: The mortality rate of rats was 60.00% (18/30) in the DMH group and 48.00% (12/25) in the DMH + NaBt group. The intestinal tumor incidence was 66. 67% (8/12) in the DMH group with four small intestinal tumors and twelve large intestinal tumors observed. Four rats beared a single tumor while other four rats had multiple tumors. The mean number of beared tumors was 1.33. The intestinal tumor incidence was 84.62% (11/13) in the DMH + NaBt group with three small intestinal tumors and sixty large intestinal tumors observed. Six rats beared a single tumor while other five rats had multiple tumors. The mean number of beared tumors was 1.46. There were no significant differences in tumor incidence and mean tumor number between te DMH + NaBt group and DMH group. The large intestinal tumor incidence was significantly higher than the small intestinal tumor incidence in both the DMH group and DMH + NaBt group (75.00% vs 25.00%, P < 0.05; 84.21% vs 15.79%, P < 0.01). There were significant differences in average tumor volume (37.50% vs 73.68%, P < 0.05) and tumor infiltration depth (43.75% vs 10.53%, P < 0.05) between the DMH group and DMH + NaBt group.

CONCLUSION: These results suggest that small intestinal tumors can also be induced by DMH. Sodium butyrate can increase tumor malignancy by increasing tumor volume and infiltration depth.

Fish oil improves the lipid profile and reduces inflammatory cytokines in Wistar rats with precancerous colon lesions

A fatty diet is regarded as one of the most important risk factors related to the etiology of colorectal cancer, and this effect is linked to the quantity and principal types of fatty acids consumed. In this study, the chemopreventive effects of different oils on rats were investigated. Forty Wistar rats received 1,2-dimetilhidrazine (DMH) and were divided into 4 groups fed normal lipid diets to which 4% olive, fish, flaxseed, or soybean oils (control) were added. The group fed with fish oil presented higher levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid in hepatic tissue and greater levels of linolenic acid and EPA in adipose tissue compared to the other treatments. In the proximal portion of the colon, lower levels of aberrant crypt foci were found in the fish and flaxseed oil groups; however, this behavior was not observed in the middle and distal regions. Via a benchmarking method, the fish oil group showed a greater transforming growth factor β expression and lower interleukin-8 expression in relation to the other treatments. Fish oil in a normal lipid diet demonstrated a limited protective effect on the colonic precancerous mucosa in carcinogen-treated rodents, whereas it had a beneficial effect on inflammatory modulation.