Patten Glen S, Adams Michael J, Dallimore Julie A, Abeywardena Mahinda Y
CSIRO Health Sciences & Nutrition, Adelaide, South Australia 5000, Australia.
J Nutr. 2004 Nov;134(11):2924-9. doi: 10.1093/jn/134.11.2924.
Dietary saturated fat (SF) has adverse effects on cardiac and vascular smooth muscle (VSM) contractility. Furthermore, VSM of spontaneously hypertensive rats (SHR) is overreactive to various biological stimuli. The aim of this study was to investigate the effects of increasing dietary fat as lard on gut contractility in SHR. Control Wistar-Kyoto (WKY) rats and SHR (13 wk old) were fed for 12 wk a diet containing 3% sunflower oil [low fat (LF), 3% total fat] or diets supplemented with 7% lard [medium fat (MF), 10% total fat] or 27% lard [high fat (HF), 30% total fat]. For ileal and colonic tissues (WKY and SHR), there was a lower total phospholipid PUFA (n-6)/(n-3) ratio with increased dietary SF (P < 0.003). For WKY, increasing SF led to lower levels of the major SCFA and lower total SCFA levels in cecal digesta (P < 0.01). This trend was evident in SHR but significant only for butyrate (P < 0.01). Contractility responses were unaltered in ileum. In colon, there was a change of sensitivity (50% effective concentration) to angiotensin II in WKY (P < 0.05) due to increased SF and a change of sensitivity to prostaglandin (PG)E(2) and carbachol in SHR (P < 0.05). When the 3 dietary groups were combined, there was lower sensitivity (P < 0.01) and lower maximal contraction (P < 0.05) in ileum and lower maximal contraction in colon of SHR in response to PGF(2alpha) (P < 0.05) and PGE(2) (P < 0.01) compared with WKY. Unlike (n-3) PUFA, dietary SF had little overall effect on gut contractility. However, this is the first report of a defect in PG responsiveness from gut tissue from hypertensive rats.
膳食饱和脂肪（SF）对心脏和血管平滑肌（VSM）的收缩性有不良影响。此外，自发性高血压大鼠（SHR）的VSM对各种生物刺激反应过度。本研究的目的是调查增加猪油形式的膳食脂肪对SHR肠道收缩性的影响。将对照Wistar-Kyoto（WKY）大鼠和SHR（13周龄）喂养12周，饲料中含有3%的向日葵油[低脂（LF），总脂肪含量3%]或添加7%猪油的饲料[中脂（MF），总脂肪含量10%]或27%猪油的饲料[高脂（HF），总脂肪含量30%]。对于回肠和结肠组织（WKY和SHR），随着膳食SF增加，总磷脂多不饱和脂肪酸（PUFA）（n-6）/（n-3）比值降低（P<0.003）。对于WKY，增加SF导致盲肠消化物中主要短链脂肪酸（SCFA）水平降低以及总SCFA水平降低（P<0.01）。这种趋势在SHR中也很明显，但仅丁酸盐有显著变化（P<0.01）。回肠的收缩反应未改变。在结肠中，由于SF增加，WKY对血管紧张素II的敏感性（半数有效浓度）发生变化（P<0.05），而SHR对前列腺素（PG）E2和卡巴胆碱的敏感性发生变化（P<0.05）。当将这三个饮食组合并时，与WKY相比，SHR回肠对PGF2α（P<0.05）和PGE2（P<0.01）的敏感性降低（P<0.01）且最大收缩力降低（P<0.05），结肠的最大收缩力降低。与多不饱和脂肪酸（n-3）不同，膳食SF对肠道收缩性总体影响较小。然而，这是关于高血压大鼠肠道组织PG反应性缺陷的首次报道。
