血脂异常对C57BL小鼠巩膜顺应性的影响

An affect of dyslipidemia on scleral compliance in experimental C57BL mice

目的探讨血脂异常对C57BL小鼠巩膜顺应性的影响。方法选用3月和8月龄C57BL雄性小鼠,按体重随机分为3组。3月龄和8月龄普食组各12只,8月龄高脂组18只。3月龄组喂养1周后处死;8月龄组喂养22周后处死;8月龄高脂组喂养4周后随机取6只处死,检测血清胆固醇(TC)和低密度脂蛋白(LDL-C),其余12只喂养至22周处死。各组动物检测血脂,同时取主动脉和眼球标本,经油红“O”、苦味酸天狼腥红等染色,用偏振光显微镜等进行组织学观察。结果造模4周后8月龄高脂组的TC和LDL-C已明显升高,与3月龄普食组比较有极显著性差异(P<0·01),确认血脂异常的动物模型。8月龄高脂组血脂指标高于3月龄、8月龄普食组,比较有显著性差异(P<0·01)。发现8月龄高脂组的主动脉和巩膜油红“O”染色有红色脂滴着染。C57BL小鼠巩膜胶原纤维主要是Ⅰ型和Ⅲ型。对Ⅰ型和Ⅲ胶原纤维的平均光密度、积分光密度、厚度及Ⅲ型/Ⅰ型胶原(ColⅢ/ColⅠ)面积比指标的检测显示,3组间Ⅰ型和Ⅲ型胶原纤维的平均光密度无差异(P>0·05),而积分光密度、厚度及ColⅢ/ColⅠ面积比均有差异(P<0·01或P<0·05)。结论血脂异常引起巩膜发生类似于动脉粥样硬化的胶原纤维Ⅲ型增生,是巩膜顺应性降低的前奏。

OBJECTIVE To observe affect of dyslipidemia on scleral compliance and changes of scleral collagen in experimental C57BL mice.METHODS Three - month - old and 8 - month - old C57BL mice were chosen, they were divided into three groups： group 1, 12 mice, 3 - month- old with normal feeding for one week and killed; group 2, 12 mice, 22 weeks with normal feeding up to 8 - month- old and killed; and group 3, 18 mice with cholesterol- rich diet for 4 weeks. At 4 weeks take 6 mice from group 3 and killed for testing TC and LDL- C.The rest 1：2 mice will be fed with same food for 22 weeks and then killed. For three groups, the serum lipid levels were determined, the eyes and aorta were uhrastructurally examined using picrosirius and oil - red “O” dyed methods to measure the changes of it. Histology study had been done with polarization microscope. RESULTS At 4 weeks, the 8 - month - old cholesterol - rich feeding group showed increase of the TC and LDL and had big difference compared with 3 - month normal feeding group （P 〈 0.01）, It confirmed the animal model of dyslipidemia. In the 8 month cholesterol- rich feeding group by using oil - red “O” dyed method the red grease dyed drops on the aorta and sclera were observed. By using picrosirius - polarizationmethod, type Ⅰ and Ⅲ were found in the scleral collagen. The mean light density, integrad light density, thickness and Col Ⅲ/Col Ⅰ area ratio have been tested towards type Ⅰ and Ⅲ. The mean light density have no difference （P 〉 0.05） among three groups, while the integral light density, thickness and Col Ⅲ/Col Ⅰ area ratio are different （P 〈 0.01 or P 〈 0.05） . CONCLUSIONS The model of dyslipidemia in C57BL mice was made successfully. Dyslipidemia can cause hyperplasia of collagen Ⅲ on the sclera. It indicates that there is an early change of reduction in scleral compliance. There is a relationship between dyslipidemia and AMD.