An in vivo study of the effects on serum glucose, amylase and histopathology of the feline pancreatic tissue treated by focused ultrasound

Abstract

Pancreatic cancer is one of the most malignant neoplasms originating in the digestive system. Focused ultrasound (FUS) treatment instead of the surgery operation has been used to treat Pancreatic cancer noninvasively in clinical trials. The endocrine and exocrine glands in pancreas provide the two unique functions for a person to be healthy. It is critically important to find out if the FUS treatment can still keep the normal functions of the two glands. The goal of this study is to examine and analyze changes in histopathology and serum glucose and amylase levels of the targeted in-vivo felines after the FUS treatment. Various percentage volumes of pancreas of felines were insonified. The FUS treatment (7.5 MHz of central frequency; 5 W of acoustical power; transducer f-number = 0.33; 6 s insonification time per point) effectively generated coagulative necrosis at the insonified site while leaving tissue outside the insonified site intact. It was also observed that all felines endured well with the FUS treatment; changes introduced to pancreatic tissue after up to 50% of a pancreas by volume was insonified by the FUS procedure did not affect its normal endocrine and exocrine functions.

Figure 1. Focused ultrasound treatment system.

Figure 2. Illustration of FUS treatment on pancreas.

Figure 3. Optical and electron microscope performance of insonified and non-insonified sites after Focused Ultrasound: A (H.E×200), Immediately after FUS, the noninsonified site, islets and exocrine cells were normal in morphology and structure; B(H.E×400) and G(×4000), immediately after Focused Ultrasound, cells in the insonified sites started irreversible necrosis process;C (H.E×200) and H(×5000), 3 days after treatment, the acinar structures were “destroyed,” karyolysis, nuclear fragmentation were observed. D (H.E×100) and I (×3500), 7 days after operation, repair process started and newborn pancreatic ducts formed; E (H.E×100) and J(×4000), 14days after operation, insonified site was replaced by fibrous connective tissue and abundant newborn pancreatic ducts formed; F(H.E×100) and K(×4000), 21days after operation, the necrosis site was replaced by fibrous tissue, pancreatic duct hyperplasia was clearly observed.

Figure 4. Changes of serum glucose level of different groups at different time-scales.

Figure 5. Changes of serum amylase of different groups at different time-scales.