Pirnik Zdeno, Bundzikova Jana, Mikkelsen Jens D, Zelezna Blanka, Maletinska Lenka, Kiss Alexander
Laboratory of Functional Neuromorphology, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Endocr Regul. 2008 Sep;42(4):137-46.
It is generally known that hypocretin (Hcrt) neurons in lateral hypothalamus (LH) are involved in feeding behaviour. The aim of this study was to reveal the activity response of Hcrt neurons, as measured by Fos protein incidence, to prolonged high fat (HF) diet in the LH of both genders of C57B1/6 mice.
Standard (St) and high fat (HF) diets were available to mice for 16 weeks and thereafter the animals were perfused transcardially with fixative. Then the brains were removed, soaked with 15 % sucrose in 0.1 M phosphate buffer (PB), and cryo-sectioned throughout the hypothalamus into 35 microm thick coronal sections. Fos/Hcrt co-localizations were processed by employing avidin-biotin-peroxidase (ABC) complex and diaminobenzidine chromogen for Hcrt labeling. Fos immunoproduct was intensified by nickel chloride as a black color inducer. Evaluation of the incidence of Fos/Hcrt co-labeled perikarya was performed using a computerized Leica light microscopy.
The effect of of mice gender, applied diet, and gender plus applied diet on the activation of Hcrt neurons was found. Turkey s test revealed significant (p<0.05) rise in Fos labeled Hcrt neurons in male vs. female mice after consumption of both types of diets: St (44.64 +/- 2.28 % vs. 1.47 +/- 0.195 %, resp.) and HF (44.15 +/- 3.77 % vs. 24.32 +/- 0.7 %, resp.). This showed that HF diet significantly elevated the number of activated Hcrt neurons only in female mice (24.32 +/- 0.7 % in HF fed vs. 1.47 +/- 0.195 % in St fed, p<0.05). The body weight and accumulation of body fat in animals (body fat weight expressed as % of body weight) were influenced by gender and applied diet, although the body fat weight was influenced by HF diet (more noticeably in females).
The data indicated a positive correlation between body weight, fat gain, and Hcrt activities in females but not in males, thus accentuating the importance of the gender impact.
众所周知，下丘脑外侧区（LH）的食欲素（Hcrt）神经元参与进食行为。本研究旨在揭示通过Fos蛋白发生率测量的C57B1/6小鼠两性LH中Hcrt神经元对长期高脂（HF）饮食的活动反应。
小鼠可自由选择标准（St）和高脂（HF）饮食16周，之后经心脏灌注固定剂处死动物。然后取出大脑，用含15%蔗糖的0.1M磷酸盐缓冲液（PB）浸泡，将下丘脑整个区域冷冻切片成35微米厚的冠状切片。采用抗生物素蛋白-生物素-过氧化物酶（ABC）复合物和二氨基联苯胺显色剂对Hcrt进行标记，处理Fos/Hcrt共定位。用氯化镍作为黑色显色剂增强Fos免疫产物。使用计算机化的徕卡光学显微镜评估Fos/Hcrt共标记核周体的发生率。
发现小鼠性别、所用饮食以及性别加所用饮食对Hcrt神经元激活有影响。t检验显示，食用两种类型饮食后，雄性小鼠中Fos标记的Hcrt神经元显著（p<0.05）多于雌性小鼠：标准饮食（分别为44.64±2.28%和1.47±0.195%）和高脂饮食（分别为44.15±3.77%和24.32±0.7%）。这表明高脂饮食仅显著增加了雌性小鼠中活化的Hcrt神经元数量（高脂饮食组为24.32±0.7%，标准饮食组为1.47±0.195%，p<0.05）。动物的体重和体脂积累（体脂重量以体重的百分比表示）受性别和所用饮食影响，尽管体脂重量受高脂饮食影响（雌性更明显）。
数据表明雌性小鼠体重、脂肪增加与Hcrt活性之间呈正相关，而雄性小鼠则不然，从而突出了性别影响的重要性。
