Sakonju I, Taura Y, Mamba K, Suzuki T, Takimoto K, Nakaichi M, Nakama S
Department of Veterinary Surgery, Yamaguchi University, Japan.
J Vet Med Sci. 1995 Oct;57(5):859-63. doi: 10.1292/jvms.57.859.
We have investigated the freezing tolerance of rat pancreatic islets. Freshly isolated rat pancreatic islets were divided into three groups based on their longest diameter (small; 100 - 200 microns, medium; 201 - 300 microns, large; > 300 microns). They were then cryopreserved at a slow cooling rate (-0.3 degrees C/min) in the presence of dimethyl sulfoxide (Me2SO) or ethylene glycol (EG). After storage at -196 degrees C for 1 - 4 weeks, they were thawed and their ability to secrete insulin in response to fluctuations in glucose concentration was examined during three consecutive static incubations in vitro (1st; 2.8 mM, 2nd; 16.7 mM, 3rd; 2.8 mM). Morphological examination of the beta-granule population was determined by image analysis, and correlation with islets size was analyzed. The amount of insulin released from large-sized islets was significantly suppressed in EG (p < 0.05) and Me2SO (p < 0.01) groups compared to unfrozen islets. However, the mean volume of the large-sized islets isolated from one rat accounted for 43.0% of the total volume. On the other hand, the amount of insulin released from small- and medium-sized islets did not differ from those of unfrozen islets, and their mean volumes were 13.2 and 43.8% respectively. The percentage of cells with beta-granules was significantly correlated with size in both EG (r = -0.52) and Me2SO (r = -0.35) groups, but no significant correlation was observed in the unfrozen islets groups. These findings suggest that large-sized islets are more susceptible to freezing injury than small- or medium-sized islets. Moreover, the volume distribution of isolated islets indicated that it may be important to retain the ability of insulin secretion from the large-sized islets.
我们研究了大鼠胰岛的耐冻性。将新鲜分离的大鼠胰岛根据其最长直径分为三组（小；100 - 200微米，中；201 - 300微米，大；> 300微米）。然后在二甲基亚砜（Me2SO）或乙二醇（EG）存在下以缓慢冷却速率（-0.3℃/分钟）进行冷冻保存。在-196℃储存1 - 4周后，将其解冻，并在连续三次体外静态孵育期间（第一次；2.8 mM，第二次；16.7 mM，第三次；2.8 mM）检测其响应葡萄糖浓度波动分泌胰岛素的能力。通过图像分析确定β颗粒群体的形态学检查，并分析与胰岛大小的相关性。与未冷冻的胰岛相比，在EG（p < 0.05）和Me2SO（p < 0.01）组中，大尺寸胰岛释放的胰岛素量显著受到抑制。然而，从一只大鼠分离的大尺寸胰岛的平均体积占总体积的43.0%。另一方面，小尺寸和中尺寸胰岛释放的胰岛素量与未冷冻的胰岛没有差异，它们的平均体积分别为13.2%和43.8%。在EG（r = -0.52）和Me2SO（r = -0.35）组中，具有β颗粒的细胞百分比与大小显著相关，但在未冷冻的胰岛组中未观察到显著相关性。这些发现表明，大尺寸胰岛比小尺寸或中尺寸胰岛更容易受到冷冻损伤。此外，分离胰岛的体积分布表明，保留大尺寸胰岛的胰岛素分泌能力可能很重要。
