新型卵母细胞载体降温速率的实验研究
Experimental Study on the Cooling Rate of a New Type of Oocyte Carriers

降温速率是决定细胞低温保存效果的关键，而冷冻载体的形式和使用方式对细胞的降温速率有重要影响。使用数字示波器、线径80 μm的T型热电偶建立起高速测温系统，研究了一种新型封闭式卵母细胞冷冻载体以不同的方式从空气插入液氮的降温速率，结果发现载体的降温主要通过对流换热实现；载体横卧时，载体的气孔方向与液氮垂直时降温速率高于气孔与液氮相切时的降温速率；将载体直接插入液氮时的降温速度大于插入后左右摆动的操作方法的降温速率；当采用载体倒置插入时，降温速度高于采用载体正置和横卧的降温速率。当采用载体倒置直接插入时，其降温速率最高，可以达到54572 ± 1338 K/min，有利于卵母细胞的玻璃化保存。
Cooling rate is the key factor that determines the cryopreserving effect of cells, which has much to do with the forms and the usages of freezing carrier. In this study, digital oscilloscopes and type T thermocouple of 80 μm diameter were employed to establish a high speed temperature measurement system. The cooling rates of cells were measured by using a new type of enclosed oocyte freezing carrier in different ways of being inserted from air to liquid nitrogen. The results showed that the cooling of freezing carrier is mainly fulfilled via heat convection; When the carriers were horizontally placed, the cooling rate of carrier when the air hole was perpendicular to liquid nitrogen is higher than that when the air hole was tangent to liquid nitrogen; when the freezing carrier was directly inserted into liquid nitrogen, the cooling rate of carrier was higher than that when the freezing carrier was inserted into liquid nitrogen and then swayed; when the freezing carrier was placed downwards, the cooling rate of carrier was higher than that vertically or horizontally placed. Based on the results mentioned above, when the carrier was directly inserted into liquid nitrogen downwards, the cooling rate could reach as high as 54572 ± 1338 K/min, which is the highest and favorable to verification of oocytes