Effect of Kaiyu Qingwei Jianji on the morphometry and residual strain distribution of small intestine in experimental diabetic rats

Abstract

Aim: To investigate the effect of a Chinese medicine, Kaiyu Qingwei Jianji (KYQWJJ) used for diabetic treatment, on the morphometry and residual strain distribution of the small intestine in streptozotocin (STZ) -induced diabetic rats. Correlation analysis was also performed between the opening angle and residual strain with the blood glucose level.

Methods: Forty-two male Wistar rats weighing 220-240 g were included in this study. Thirty-two STZ-induced diabetic rats were subdivided into four groups (n = 8 in each group), i.e. diabetic control group (DM); high dose of KYQWJJ (T1, 36 g/kg per day); low dose of KYQWJJ (T2, 17 g/kg per day) and Gliclazide (T3, 50 mg/kg per day). Another ten rats were used as non-diabetic control (CON). The medicines were poured directly into stomach lumen by gastric lavage twice daily. The rats of CON and DM groups were only poured the physiological saline. Blood glucose and plasma insulin levels were measured. Experimental period was 35 d. At the end of experiment, three 5-cm long segments were harvested from the duodenum, jejunum and ileum. Three rings of 1-2 mm in length for no-load and zero-stress state tests were cut from the middle of different segments. The morphometric data, such as the circumferential length, the wall thickness and the opening angle were measured from the digitized images of intestinal segments in the no-load state and zero-stress state. The residual strain was computed from the morphometry data. Furthermore, the linear regression analysis was performed between blood glucose level with morphometric and biomechanical data in the different intestinal segments.

Results: The blood glucose level of DM group was consistent 4-fold to 5-fold higher than those in CON group during the experiment (16.89+/-1.11 vs 3.44+/-0.15 mmol/L, P < 0.001). The blood glucose level in the T1 (16.89+/-1.11 vs 11.08+/-2.67 mmol/L, P < 0.01) and T3 groups (16.89+/-1.11 vs 13.54+/-1.73 mmol/L, P < 0.05), but not in T2 group (P > 0.05) was significantly lower than those in DM group. The plasma insulin levels of DM, T1, T2 and T3 groups were significantly lower than those in CON group (10.98+/-1.02, 12.52+/-1.42,13.54+/-1.56,10.96+/-0.96 vs 17.84+/-2.34 pmol/L respectively, P < 0.05), but no significantly difference among the groups with exception of CON group. The wet weight/cm and total wall thickness of duodenum, jejunum and ileum in DM group were significantly higher than those in CON group (wet weight (g/cm): duodenum 0.209+/-0.012 vs 0.166+/-0.010, jejunum 0.149+/-0.008 vs 0.121+/-0.004, ileum 0.134+/-0.013 vs 0.112+/-0.007; Wall thickness (mm): duodenum 0.849+/-0.027 vs 0.710+/-0.026, jejunum 0.7259+/-0.034 vs 0.627+/-0.025, ileum 0.532+/-0.023 vs 0.470+/-0.010, all P < 0.05), T1 and T3 treatment could partly restore change of wall thickness, but T2 could not. The opening angle and absolute value of inner and outer residual stain were significantly smaller in duodenal segment (188+/-11 degrees, -0.31+/-0.02 and 0.35+/-0.03 vs 259+/-15 degrees, -0.40+/-0.02 and 0.43+/-0.05) and larger in jejunal (215+/-20 degrees, -0.30+/-0.03 and 0.36+/-0.06 vs 172+/-19 degrees, -0.25+/-0.02 and 0.27+/-0.02) and ileal segments (183+/-20 degrees, -0.28+/-0.01 and 0.34+/-0.05 vs 153+/-14 degrees, -0.23+/-0.03 and 0.29+/-0.04) in DM group than in CON group (P < 0.01). T1 and T3 treatment could partly restore this biomechanical alteration, but strong effect was found in T1 treatment (duodenum 243+/-14 degrees, -0.36+/-0.02 and 0.42+/-0.06, jejunum 180+/-15 degrees, -0.26+/-0.03 and 0.30+/-0.06 and ileum 163+/-17 degrees, -0.23+/-0.03 and 0.30+/-0.05, compared with DM, P < 0.05). The linear association was found between the glucose level with most morphometric and biomechanical data.

Conclusion: KYQWJJ (high dose) treatment could partly restore the changes of blood glucose level and the remodeling of morphometry and residual strain of small intestine in diabetic rats. The linear regression analysis demonstrated that the effect of KYQWJJ on intestinal opening angle and residual strain is partially through its effect on the blood glucose level.

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Figure 1

The blood glucose levels in different groups, compared with DM group (^bP < 0.01).

Figure 2

The serum insulin levels in different groups, compared with DM group (^aP < 0.05).

Figure 3

The intestinal wet weight of different segments per centimeter long in different groups, compared with DM group (^bP < 0.01).

Figure 4

The intestinal wall thickness of different segments in different groups, compared with DM group (^aP < 0.05; ^bP < 0.01).

Figure 5

The opening angles of different intestinal segments in different groups, compared with DM group (^aP < 0.05; ^bP < 0.01).

Figure 6

The inner (A) and outer (B) residual strain distribution of different intestinal segments in different groups, compared with DM group (^aP < 0.05; ^bP < 0.01).

Figure 7

The examples of association between the glucose with opening angle (A) and inner residual strain (B) in duodenal segment.