| Objectiv①To observe morphologic changes of the submandibular gland tissues of diabetic rats under light microscope, and to analyze the influence of diabetes mellitus on acinus average circumference and GCT average diameter of the submandibular glands tissues of diabetic rats by morphometrics;㈡To study the altered experssion and significances of AQP1and AQP5in the ductal epithelial cells of the submandibular gland of diabetic rats,and to calculate MOD of AQP1and AQP5in the submandibular glands of diabetic rats;③To observe the effects and significances of Insulin on altered expression of AQP1and AQP5in the ductal epithelial cells of the submandibular glands of diabetic rats. Methods30Sprague-Dawley rats were randomly divided into the control group, the diabetic group and the therapy group. The rats of control group were given normal diet. The rats of the diabetic group were first fed with high fat diet for2months. After coming into being insulin resistance (IR) and impaired glucose tolerance symptoms, the rats of the diabetic group were intraperitoneally injected with2%Streptozotocin (STZ,35mg. Kg-1) once to selectively destruct part of the pancreatic beta cells for replication of type2diabetes model rats, and were fed with normal diet. After one week, detection of fasting blood glucose>7.0mmol/L, prompted diabetic rats model was successful. After replication of type2diabetes model rats using the same method of the diabetic group, the rats of the therapy group were given insulin therapy,3u/d, and were fed with normal diet. The rats in each group cloud drink water freely. After continuous feeding for2months, the rats in each group were sacrificed for assaying the blood glucose and serum lipids; then the submandibular gland tissues were removed for the following treatments:HE staining, immunohistochemistry staining,histomorphometric analysis of acinar average circumference, GCT average diameter; and calculate MOD of AQP1and AQP5by computer image analysis software. Results①Blood glucose test results:After feeding for2months, blood glucose of the control group (4.1919±1.1668) and the therapy group (5.8513±1.8247) was respectively compared with that of the diabetic group (15.4700±7.1032), the differences were significant (P<0.05); blood glucose of the control group was compared with that of the therapy group, the difference was not significant (P>0.05). The difference between the therapy group one week after modeling (10.9575±4.1272) and the therapy group2months after modeling (5.8513±1.8247) was significant (P<0.05).②Blood serum lipids test results:After feeding for2months, the control group TG (0.7848±0.2127) and the therapy group TG (0.8382±0.4921) were respectively compared with the diabetic group TG (1.4951±0.5567), the differences were significant (P<0.05); the control group TG was compared with that of the therapy group, the difference was not significant (P>0.05). After feeding for2months, the control group TC (1.2506±0.3539) and the therapy group TC (3.6283±0.7274) were respectively compared with the diabetic group TC (9.6081±5.2476), the differences were significant (P<0.05); the control group TC was compared with that of the therapy group, the difference was not significant (P>0.05).③HE staining:the submandibular glands of the control group were clear, composed by the acinar portion and the duct portion. The submandibular glands were mixed glands, including more serous glands and fewer mucous glands; the duct system included intercalated duct, granular convoluted tubule (GCT), striated duct and excretory duct. The acinar portion in the control group was full and clear. Ductal cpithclical cells of GCT was full; and much acidophilia secretory granules were in cytoplasm of ductal epithelical cells of GCT, besides the nucleus was round. After2months, the acinar significantly atrophy and the acinar cells were arranged irregularly in the submandibular glands of the diabetic group rats, and local connective tissue proliferation was significant, the structure of the submandibular glands of the therapy group rats was clear; the acinar cells and ductal epithelical cells were full and arranged regularly.④The result of immunohistochemistry:the expression of AQP1and AQP5was dark brown in the ductal epithelial cells of the submandibular glands of the control group, The immune response of cell nucleus and the acinus appeared negative; in comparison with the control group, the expression of AQP1and AQP5was reduced in the diabetic group, appearing light brown; in comparison with the diabetic group, the expression of AQP1and AQP5was increased in the therapy group, appearing brown.⑤histomorphometric analysis result:acinus average circumference (110.3289±14.1815) and GCT average diameter (42.2819±3.9746) in the control group, were respectively compared with acinus average circumference (83.1598±5.7230) and GCT average diameter (31.3653±2.7664) in the diabetic group, the differences were significant(p<0.05). Acinus average circumference (103.1355±12.7654) and GCT average diameter(40.6947±5.3601) of the therapy group, were respectively compared with those of the diabetic group, the differences were significant(p<0.05). Acinus average circumference and GCT average diameter of the therapy group were respectively compared with those of the control group, the differences were not significant(p>0.05).⑤computer image analysis:the MOD of AQP1(0.3041±0.0181) and AQP5(0.3299±0.0302) in the control group was respectively compared with the MOD of AQP1(0.2099±0.0240) and AQP5(0.2107±0.0180) of the diabetic group, the differences were significant(p<0.05); the MOD of AQP1(0.2834±0.0218) and AQP5(0.2946±0.0166) in the therapy group was respectively compared with those of the diabetic group, the differences were significant (P<0.05); comparison between the MOD of AQP1in the control group and that of the therapy group was not significant (P>0.05):Comparison between the MOD of AQP5in the control group and that of the therapy group was significant (P<0.05). Conclusion①the acinar atrophy and the acinar cells were arranged irregularly in the diabetic group; acinar average circumference and GCT average diameter were decreased.②Expression of AQP1and AQP5was suppressed in the ductal epithelial cells of the submandibular glands of diabetic rats; but expression of AQPland AQP5was increased of diabetic rats treated with insulin.③The reduced expression of AQP1and AQP5of the submandibular glands in the diabetic rats, may be one important reason for diabetes thirsty; then insulin can significantly reduce structure and functional damage of the submandibular gland of diabetic rats. |
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