Objective:To study the mesenteric lymphatic contractility and intestinal blood perfusion in rats with type I diabetes mellitus caused by streptozocin (STZ).Methods:SPF Wistar rats (12-week-old) weighing 190～220 g (16 animals in total) were randomly divided into control group and type I diabetes group. STZ was injected intraperitoneally to induce type I diabetes. One week later, the intestinal blood perfusion was observed by PeriCam PSI System, which is a blood perfusion imager based on the laser speckle contrast analysis (LASCA) technology. The mesenteric lymphatic contractility of rats was observed by dynamic visualization microcirculation research system (Gene & I). The wet-dry ratios of intestinal tissues were measured to estimate the edema condition.Results:Compared with that of normal rats, the intestinal blood perfusion of diabetic rats was significantly increased (243.21±9.19vs199.33±10.33,P<0.05). Meanwhile, the wet-dry ratio of intestinal tissues was also significantly elevated (5.10±0.09vs4.43±0.08,P<0.05) in the type I diabetes group. Whereras, the contractility of mesenteric lymphatic vessels in the diabetic rats was comparable with that in the control group (P>0.05), evidenced by comparable lymphatic fractional contraction (Index I), overall lymphatic contractile activity (Index II) and peristalsis dynamics of lymphatic vessel (L.D. Index).Conclusion:One week after STZ induction, the rats with type I diabetes showed increased intestinal edema and increased intestinal blood perfusion, but the mesenteric lymphatic contractility was not affected.