Abstract Pancreatic islet microcirculation, consisting of pancreatic islet microvascular endothelial cells (IMECs) and pericytes (IMPCs), provides crucial support for the physiological function of pancreatic islet. Emerging evidence suggests that pancreatic islet microcirculation is impaired in type 1 diabetes mellitus (T1DM). Here, we investigated the potential ultrastructural protective effects of insulin against streptozotocin (STZ)-induced ultrastructural abnormalities of the pancreatic islet microcirculation in T1DM mouse model. For this purpose, pancreatic tissues were collected from control, STZ-induced T1DM and insulin-treated mice, and a pancreatic IMECs cell line (MS1) was cultured under control, 35 mM glucose with or without 10−8 M insulin conditions. Transmission and scanning electron microscopies were employed to evaluate the ultrastructure of the pancreatic islet microcirculation. We observed ultrastructural damage to IMECs and IMPCs in the type 1 diabetic group, as demonstrated by destruction of the cytoplasmic membrane and organelles (mainly mitochondria), and this damage was substantially reversed by insulin treatment. Furthermore, insulin inhibited collagenous fiber proliferation and alleviated edema of the widened pancreatic islet exocrine interface in T1DM mice. We conclude that insulin protects against T1DM-induced ultrastructural abnormalities of the pancreatic islet microcirculation.

中文翻译：

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胰岛素预防 1 型糖尿病引起的胰岛微循环超微结构异常

摘要 胰岛微循环由胰岛微血管内皮细胞（IMECs）和周细胞（IMPCs）组成，为胰岛的生理功能提供重要支持。新出现的证据表明胰岛微循环在 1 型糖尿病 (T1DM) 中受损。在这里，我们研究了胰岛素对链脲佐菌素 (STZ) 诱导的 T1DM 小鼠模型胰岛微循环超微结构异常的潜在超微结构保护作用。为此，从对照、STZ 诱导的 T1DM 和胰岛素治疗的小鼠中收集胰腺组织，并在对照、35 mM 葡萄糖和 10-8 M 胰岛素条件下培养胰腺 IMECs 细胞系 (MS1)。采用透射和扫描电子显微镜评估胰岛微循环的超微结构。我们观察到 1 型糖尿病组中 IMEC 和 IMPC 的超微结构损伤，如细胞质膜和细胞器（主要是线粒体）的破坏所证明的，并且这种损伤被胰岛素治疗显着逆转。此外，胰岛素抑制胶原纤维增殖并减轻 T1DM 小鼠扩大的胰岛外分泌界面的水肿。我们得出结论，胰岛素可以防止 T1DM 引起的胰岛微循环超微结构异常。正如细胞质膜和细胞器（主要是线粒体）的破坏所证明的那样，胰岛素治疗可以大大逆转这种损伤。此外，胰岛素抑制胶原纤维增殖并减轻 T1DM 小鼠扩大的胰岛外分泌界面的水肿。我们得出结论，胰岛素可以防止 T1DM 引起的胰岛微循环超微结构异常。正如细胞质膜和细胞器（主要是线粒体）的破坏所证明的那样，胰岛素治疗可以大大逆转这种损伤。此外，胰岛素抑制胶原纤维增殖并减轻 T1DM 小鼠扩大的胰岛外分泌界面的水肿。我们得出结论，胰岛素可以防止 T1DM 引起的胰岛微循环超微结构异常。