Effect of water-soluble Silicon on Fatty Liver and Reducing Faecal Odour in mice fed a High-fat Diet

Suppressive Effects of Water-Soluble Silicon on

Fatty Liver and Fecal Odor in High-Fat Diet-Fed Mice

Kazutoshi Sugita, Asami Kawai, Akishi Shirai, Takahiko Takagi,

Sumio Goto, Fumitoshi Asai

JVM, Vol. 68, No. 11, November 2015, pp. 843-847

Abstract This study examined the effects of supplementation with water-soluble silicon on liver injury and fecal indole concentration in C57BL/6NCr mice fed a high-fat diet. Nine weeks of high-fat diet feeding (60% kcal) induced hepatic steatosis and an increase in fecal indole concentration. Seven weeks of administration of water-soluble silicon reduced hepatic steatosis and significantly suppressed the increase in fecal indole concentration.

Keywords: water-soluble silicon, high-fat diet, indole, fecal odor, mice

1. Introduction

Silicon (Si; atomic number 14) is considered an essential trace element because it is necessary for bone formation and deficiency leads to abnormalities in connective and bone tissues. It is known to be highly distributed in connective tissues such as bone, skin, arteries, hair, and nails. Silicon has been used as a supplement to prevent postmenopausal osteoporosis because it suppresses bone loss in ovariectomized rats, but its effects on lifestyle-related diseases are largely unknown. This study investigated the effects of water-soluble silicon on lifestyle-related diseases, especially fatty liver, and on unpleasant odors such as fecal odor, using high-fat diet-fed mice. Water-soluble silicon is produced by treating high-purity quartz raw stones and specific silicate plant fibers in a high-temperature vapor extraction system, yielding a silicon-oxygen compound solution.

1 Kazutoshi SUGITA, Yukihiko TAKAGI & Sumio GOTO: Laboratory of Public Health, Azabu University, School of Veterinary Medicine, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan2 Asami KAWAI, Mitsuyuki SHIRAI & Fumitoshi ASAI: Laboratory of Pharmacology, Azabu University, School of Veterinary MedicineCorresponding Author: Akishi Shirai, E-mail: shirai@azabu-u.ac.jp

2. Materials and Methods

1) AnimalsMale C57BL/6NCr mice purchased from Japan SLC Inc. were used. Animals were housed in SPF rooms (temperature 21 ± 2°C, humidity 55 ± 5%, 12-hour light-dark cycle). Standard diet (CRF-1, Oriental Yeast Co., Ltd.) and high-fat diet (lard-based, 60% energy solid feed, DIO/60% Energy F/Fat PD Blue:58Y1, Japan SLC Inc.) were used. All experiments were approved by the Azabu University Animal Experiment Committee.

2) Test SubstanceA concentrated solution of water-soluble silicon (UMO concentrated solution, 8.37 mg/mL water-soluble silicon; APA Corporation) was used. It was administered by adding it to drinking water. The low-dose group received 1% (v/v) and the high-dose group 10% (v/v) silicon solution.

3) Experimental ProtocolMice were divided into four groups:

1. Control group (standard diet + tap water, n=12)

2. High-fat diet + tap water group (n=12)

3. High-fat diet + low-dose silicon (83.7 μg/mL, n=11)

4. High-fat diet + high-dose silicon (837 μg/mL, n=12)

High-fat diet feeding began at 5 weeks of age, and water-soluble silicon administration started at 7 weeks. Food and water were provided ad libitum. Body weight, food intake, and water intake were measured weekly. The study concluded at 14 weeks of age.

4) Blood Sampling and Liver CollectionAfter a 12-hour fast, mice were anesthetized with pentobarbital sodium, and blood was collected from the abdominal vena cava with heparin as an anticoagulant. Plasma was separated by centrifugation (3000 rpm, 15 min). Mice were euthanized with an overdose of pentobarbital, and livers were collected, weighed, and fixed in 10% neutral buffered formalin. Fresh feces were collected in sterile tubes and stored at -20°C until analysis of fecal odor components.

5) Blood Biochemical AnalysisAST, ALT, glucose (Glu), triglycerides (Tg), total cholesterol (TC), and phospholipids (PL) were measured using an automated analyzer JCA-BM2250 (JEOL Ltd.).

6) Histopathological Examination of the LiverCollected livers were sectioned according to standard methods. Hematoxylin-eosin (HE) staining and Oil Red O staining for fat were performed.

7) Measurement of Fecal Indole ConcentrationFecal indole was measured using solid-phase microextraction (SPME) and GC/MS. Approximately 20 mg of feces was placed in a 2 mL vial, capped with a Teflon septum, and frozen until analysis (-20°C). A 100 μm PDMS SPME fiber was used to adsorb gas from the vial at 40°C for 30 min, followed by GC/MS analysis (Agilent GC7890/MSD5975C).

8) Statistical AnalysisResults were expressed as mean ± standard error. One-way ANOVA was performed, followed by Tukey’s multiple comparison test if differences were observed. p<0.05 was considered statistically significant.

3. Results

1) Body Weight, Food Intake, and Water IntakeMice fed a high-fat diet + tap water showed significant weight gain from 9 to 14 weeks of age compared to the control group, indicating diet-induced obesity. High-fat diet + high-dose silicon showed similar weight gain to the high-fat + water group, while the low-dose silicon group tended to have suppressed weight gain.

Food intake increased, and water intake decreased in high-fat diet-fed mice. Water intake tended to decrease in the low- and high-dose silicon groups compared to high-fat + water, possibly due to the bitter taste of silicon.

2) Blood Biochemical AnalysisGlu, Tg, TC, and PL were significantly increased in high-fat diet-fed mice. AST and ALT tended to be higher but were not statistically significant. Both low- and high-dose silicon groups showed lower AST and ALT values compared to high-fat + water group (Table 1).

3) Liver Weight and HistopathologyLiver weight significantly increased in high-fat + water mice compared to controls. The low-dose silicon group showed no significant difference from control and tended to have lower liver weight than high-fat + water (Fig. 2).

Histologically, control livers showed no abnormalities (Fig. 3A).

High-fat + water group exhibited moderate centrilobular hepatic steatosis (Fig. 3B). High-fat + high-dose silicon showed similar steatosis (Fig. 3D),

whereas the low-dose silicon group had only very mild to mild centrilobular and scattered/diffuse steatosis (Fig. 3C).

4) Fecal Indole Concentration

Fecal indole concentration approximately doubled in high-fat diet-fed mice compared to control. Both low- and high-dose silicon groups had significantly lower indole concentrations compared to high-fat + water, close to control levels (Fig. 4).

4. Discussion

High-fat diet feeding increased liver weight and induced hepatic steatosis, causing fatty liver. Low-dose water-soluble silicon (83.7 μg/mL in drinking water) suppressed liver weight gain and limited hepatic steatosis to very mild levels, suggesting potential prevention of fatty liver. However, high-dose silicon (837 μg/mL) did not show preventive effects, indicating no dose-dependent effect; further studies are needed to determine the optimal dose and mechanism.

High-fat diet also increased fecal indole concentration, which was significantly suppressed by silicon supplementation. Although the mechanism requires further investigation, the mild antibacterial properties of water-soluble silicon may act against indole-producing bacteria. Since indole is a major component of fecal odor, water-soluble silicon is expected to reduce not only fecal odor but also potentially breath and body odor.

Referrence

1) Carlisle.E.M. (1972):Science 10,178,619-621.

2) Carlisle,E.M. (1981) :Calcif. Tissue Int.239,333-334.

3) Jugdaohsingh,R. (2007) : J. Nutr. Health Aging. 11.99-110.

4) Nielsen,F.H. & Sandstead,H.H. (1974) : Am. J. Clin. Nutr. 27, 515-520.

5) Rico, H., Gallego-Lago.J.L., Hernández, E.R. et al. (2000): Calcif Tissue Int. 66, 53-55.

6) Schwarz, K. & Milne,D.B. (1972) :Nature 239, 333-334.JVM Vol. 68 No.11, 2015　　　　　　　　　　　　　　846

Effect of Water-soluble Silicon on Liver Damage and Fecal Odor in High-fat Diet-fed Mice

Kazutoshi SUGITA 1. Asami KAWAI2, Mitsuyuki SHIRAI*2, Yukihiko TAKAGI*1. Sumio GOTO 1, Fumitoshi ASAI 2

*1Laboratory of Veterinary Public Health I, School of Veterinary Medicine, Azabu University. Sagamihara, Kanagawa 252-5201, Japan.

*2 Laboratory of Veterinary Pharmacology. School of Veterinary Medicine, Azabu University

Summary

The present study was performed to examine the effects of dietary supplementation with water-soluble silicon on the fecal indole level and liver damage in C57BL/6NCr mice fed a high-fat diet. Increases in fecal indole levels and fatty degeneration in the liver were observed in mice fed the high-fat diet (60% kcal) for 9 weeks. Seven-week supplementation with water-soluble silicon attenuated the liver damage, and significantly and dose-dependently reduced fecal indole concentrations.

Key words: water-soluble silicon, high-fat diet, indole, fecal odor, mice

J. Vet. Med. (Tokyo) Vol.68 No.11, 843-847

847JVMVol. 68 No.11, 2015

Note: This paper is translated from the following URL. The content is provided for reference on the scientific research of the raw material only. Whether APA raw materials are used or not, we hope this research will help increase understanding and awareness of body minerals.