Effects of different collagenase digestion on yield rate of purified islets in rats

Abstract

Objective To compare the yield rate of rats islets between different collagenase digestion groups.Methods The SD rats were randomly divided into two groups as following by using random digits table:collagenase P group (pancreas digested by 1 mg/ml collagenase P) and type Ⅴ collagenase group (pancreas digested by 1 mg/ml type Ⅴ collagenase).After pancreas digestion,rat islet cells in two groups were culture,purified and stained with DTZ.The mean islet number and islet equivalent (IEQ) before and after purification were measured under an inverted microscope.The viability of purified islets was assessed by fluorescence staining of aridine orange (AO) and propidium iodide (PI) under the fluorescence microscopy.After purification and culture for two days,islets function was evaluated by insulin releasing tests in the two groups.Results Before purification,there was no significant difference in the islets number obtained from the pancreas between two groups (P＞0.05),but there was significant difference in the IEQ (P＜0.05).After purification,the islets number in type Ⅴcollagenase group and collagenase P group was (485 ± 113)/pancrease and (643 ± 82)/pancrease,and IEQ was (674 ± 157)/pancreas and (989 ± 126)/pancreas,respectively (P＜0.05).Islet viability in type Ⅴcollagenase group and collagenase P group was (96.13 ±1.13) ％ and (96.38 ± 0.92) ％ respectively (P＞0.05).The results of insulin releasing tests revealed there was no significant difference in islet function stimulated by hypoglycemia and hyperglycemia between two groups (P＞0.05).Conclusion Two types of collagenase are suitable for the islets digestion in rats.The stability of digestion and yield rate of purified islets in collagenase P group are higher than in type Ⅴ collagenase group. Key words: Rats; Pancreas; Digestion; Collagenases