Effects of tetramethylpyrazine phosphate on pancreatic islet microcirculation in SD rats
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Abnormal islet microcirculation impetus the insulin production and accelerates progression of Type 1 and 2 diabetes. In this study, we investigated whether tetramethylpyrazine phosphate (TMPP), a vasoactive substance, could regulate the islet microcirculation and insulin concentration and improve glycaemia in SD rats.
SD rats were randomly divided into two groups, the control and TMPP groups. Each group was further divided into three subgroups according to the intravenous injection of either saline, 15 or 30% glucose. The non-radioactive microsphere technique was adopted to measure the organ blood flow. Nitric oxide synthase (NOS) blocker l-NAME was used to address whether NO was involved in mediating the vasoactive effects of TMPP.
In the TMPP group, TMPP increased the PBF (pancreatic blood flow), IBF (islet blood flow), and fIBF (fraction of islet blood flow out of pancreatic blood flow) by 57, 76 and 47%, respectively, after 30% glucose infusion, compared with the control, indicating that TMPP could regulate islet microcirculation. Furthermore, TMPP induced a 66% elevation of IBF and 37% of fIBF in the 30% glucose subgroups than the 15% ones. In 30% glucose-treated subgroups, TMPP improved the blood glucose concentration by 10%, compared with the control (19.3 ± 0.64 vs 17.32 ± 0.56 mmol/l, P < 0.05), without influencing the insulin secretion. Blocking NO formation prevented the enhanced PBF and IBF, evoking by TMPP with 30% glucose.
TMPP can regulate the pancreatic islet microcirculation and possess a hypoglycemia effect after glucose infusion through affecting the islet microcirculation.
KeywordsTMPP Islet microcirculation The non-radioactive microsphere technique
The work was supported by Grants of the Shanghai Municipal Health Project grant (Grant no. 2013ZYJB0802 to Xin Gao) and Shanghai Health and Family Planning Commission Foundation (Grant nos. 12GWZX0103 and 2013SY005 to Xin Gao). The author sincerely thanks the central Laboratory of Zhongshan Hospital and Institute of chronic metabolic diseases of Fudan University.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
The study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Technical Department. The animal protocol was reviewed and approved by The Animal Ethics Committee of Zhongshan Hospital, Fudan University. This article does not contain any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
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