Exploration for unknown substances in rapeseed oil that shorten survival time of stroke-prone spontaneously hypertensive rats

Ohara, Naoki; Naito, Yukiko; Nagata, Tomoko; Tatematsu, Kenjiro; Fuma, Shin-ya; Tachibana, Shigehiro; Okuyama, Harumi

doi:10.1016/j.fct.2005.11.004

Cited by 21 publications

(20 citation statements)

References 23 publications

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“…Similar anti-nutritional activities of canola oil have been observed in rats of other strains (Naito et al, 2000b), mice (Kameyama et al, 1996) and pigs (Sauer et al, 1997;Innis and Dyer, 1999). Although the survival-shortening factor in canola oil had been assumed to be phytosterols (Ratnayake et al, 2000b), the factor and the phytosterols have been partially separated by a CO 2 -supercritical fluid extraction method, indicating that a factor other than triacylglycerol and phytosterols is involved in the survival shortening (Tatematsu et al, 2004a;Ohara et al, 2006). The purpose of this study was to obtain clues for finding the factor.…”

Section: Introductionmentioning

confidence: 71%

Testosterone-lowering activity of canola and hydrogenated soybean oil in the stroke-prone spontaneously hypertensive rat

et al. 2010

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-Canola and some other types of oil unusually shorten the survival of stroke-prone spontaneously hypertensive rats (SHRSP), compared with soybean oil, perilla oil and animal fats. Since differential effects of canola and soybean oil on steroid hormone metabolism were suggested by a preliminary DNA microarray analysis as a reason for this, the steroid hormone levels in the serum and tissues of SHR-SP fed different oils were investigated. The testosterone levels in the serum and the testes were found to be significantly lower in the canola oil group than in the soybean oil group, while no significant differences were detected in the corticosterone and estradiol levels in tissues. In a second experiment, it was found that hydrogenated soybean oil, with a survival-shortening activity comparable to that of canola oil, also decreased the testosterone level in testes to a similar degree. The testosterone-lowering activity of canola and hydrogenated soybean oil observed in SHRSP was considered in relation to other factors possibly affecting the physiology of SHRSP.

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Section: Introductionmentioning

confidence: 71%

Testosterone-lowering activity of canola and hydrogenated soybean oil in the stroke-prone spontaneously hypertensive rat

et al. 2010

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“…Previous studies suggested that CO ingestion shortens the life of SHRSP via an acceleration of hypertension-related conditions, including elevation of blood pressure and tissue lesions in the kidney and heart (Naito et al, 2003;Ohara et al, 2006). On the other hand, it was found that CO ingestion elevated blood pressure and plasma lipids and caused vascular lesions not only in SHRSP but in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats (Naito et al, 2000a(Naito et al, , 2000b.…”

Section: Introductionmentioning

confidence: 96%

“…CO ingestion induced renal lesions and a tendency towards increased plasma lipids and decreased platelet counts (Ohara et al, 2006). In SHRSP, an 8-week period was thought to be a limit, as it would have been dif--lar deterioration in conditions and death due to stroke.…”

Section: Animals and Breedingmentioning

confidence: 99%

“…In this study, the single concentration of 10 w/w% (24.8 energy percentage) was adopted because the purpose of the study was not to detect dose-dependent changes due to CO ingestion, but rather, merely to confirm whether or not the increase in plasma lipids and renal lesions found in SHRSP, SHR and WKY rats given 10 w/w% CO (Naito et al, 2000a(Naito et al, , 2000b(Naito et al, , 2003Ohara et al, 2006) would also be found in Wistar rats.…”

Section: Animals and Breedingmentioning

confidence: 99%

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Dietary intake of rapeseed oil as the sole fat nutrient in wistar rats - Lack of increase in plasma lipids and renal lesions -

et al. 2008

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INTRODUCTIONLow erucic acid rapeseed (canola) oil (CO) has been reported to shorten survival times in stroke-prone spontaneously hypertensive rats (SHRSP), compared with rats given soybean oil (SO), when each oil was added at 10 w/w% to standard rat chow (Huang et al., , 1997Miyazaki et al., 1998). Previous studies suggested that CO ingestion shortens the life of SHRSP via an acceleration of hypertension-related conditions, including elevation of blood pressure and tissue lesions in the kidney and heart (Naito et al., 2003;Ohara et al., 2006). On the other hand, it was found that CO ingestion elevated blood pressure and plasma lipids and caused vascular lesions not only in SHRSP but in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats (Naito et al., 2000a(Naito et al., , 2000b. However, such unfavorable effects have been found exclusively in SHRSP and its closely related strains, and there have been no reports on CO-induced effects using rats of other strains. Therefore, the present study examined whether or not such unfavorable effects of CO are restricted to SHRSP and its related strains. For this purpose Wistar rats, the strain from which WKY rats, SHR and SHRSP were derived, were fed a diet containing 10 w/w% CO as the sole fat nutrient for 10 weeks, and the resulting changes in clinical signs were compared with those in control rats fed SO instead of CO. MATERIALS AND METHODS Animals and breedingSixteen male Wistar rats, 4 weeks old, were purchased ABSTRACT -Dietary rapeseed (canola) oil (CO) given as the only fat nutrient shortens life in strokeprone spontaneously hypertensive rats (SHRSP), compared with SHRSP given soybean oil (SO) instead of CO. CO ingestion increases plasma lipids and causes renal lesions in SHRSP and in spontaneously hypertensive rats (SHR), and increases plasma lipids also in Wistar Kyoto (WKY) rats, a normotensive counterpart of SHR. This study examined whether or not such unfavorable effects of CO are restricted to these closely related strains. For this purpose Wistar rats, the strain from which these strains were derived, were fed a diet containing 10% CO or SO as the sole fat nutrient for 10 weeks, and changes in clinical signs, urinalysis, blood biochemistry and pathology were compared. CO ingestion did not induce Na + , compared with the SO group. Thus, the unfavorable effects of CO ingestion appear to be restricted to SHRSP and its closely related strains. The role of increased aldosterone and Na + in the unfavorable events caused by CO in SHRSP, SHR and WKY rats, and any factors which could induce such increases in aldosterone and Na + , remain to be elucidated.

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“…However, conflicting results have shown no clear correlation between the content of phytosterols in the diet and tissues and survival time observed. [9,10] In addition, it has been common practice that SHRSP fed canola oil also receive a 1% NaCl loading to accelerate the development of hypertension. [1][2][3][4][5][6] A potential shortcoming of previous studies is the NaCl loading may be masking the effects of canola oil consumption alone in the SHRSP rat.…”

Section: Introductionmentioning

confidence: 99%

Salt Loading in Canola Oil Fed SHRSP Rats Induces Endothelial Dysfunction

Papazzo¹,

Lexis²,

Lewandowski³

2011

Journal of Hypertension

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This study aimed to determine if 50 days of canola oil intake in the absence or presence of salt loading affects: (1) antioxidant and oxidative stress markers, (2) aortic mRNA of NADPH oxidase (NOX) subunits and superoxide dismutase (SOD) isoforms and (3) endothelial function in SHRSP rats. SHRSP rats were fed a diet containing 10 wt/wt% soybean oil or 10 wt/wt% canola oil, and given tap water or water containing 1% NaCl for 50 days. Without salt, canola oil significantly increased RBC SOD, plasma cholesterol and triglycerides, aortic p22phox , NOX2 and CuZn-SOD mRNA, and decreased RBC glutathione peroxidase activity. With salt, canola oil reduced RBC SOD and catalase activity, LDL-C, and p22phox mRNA compared with canola oil alone, whereas plasma malondialdehyde (MDA) was reduced and RBC MDA and LDL-C were higher. With salt, the canola oil group had significantly reduced endothelium-dependent vasodilating responses to ACh and contractile responses to norepinephrine compared with the canola oil group without salt and to the WKY rats. These results indicate that ingestion of canola oil increases O 2 2 generation, and that canola oil ingestion in combination with salt leads to endothelial dysfunction in the SHRSP model.

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Exploration for unknown substances in rapeseed oil that shorten survival time of stroke-prone spontaneously hypertensive rats

Cited by 21 publications

References 23 publications

Testosterone-lowering activity of canola and hydrogenated soybean oil in the stroke-prone spontaneously hypertensive rat

Testosterone-lowering activity of canola and hydrogenated soybean oil in the stroke-prone spontaneously hypertensive rat

Dietary intake of rapeseed oil as the sole fat nutrient in wistar rats - Lack of increase in plasma lipids and renal lesions -

Salt Loading in Canola Oil Fed SHRSP Rats Induces Endothelial Dysfunction

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