Effect of calponin on fibroblast proliferation and apoptosis in burn wound of diabetic rats

Abstract

Objective To discuss the expression of calponin in burn wound healing process of diabetic rats and its effect on the proliferation and apoptosis of fibroblasts. Methods Sixty-four Wistar male rats were selected and divided into the experimental group and the control group according to the random number table method, with 32 rats in each group. Rats in the experimental group were given intraperitoneal injections with streptozotoci by 60 mg/kg to create diabetic animal model. Rats in the control group were given 0.9% sodium chloride solution with 1.0 mL. Deep partial-thickness scald models (hereinafter referred to as burns) were produced in all rats at the time of adaptive feeding after 2 weeks. Liquid recovery and routine treatment were immediately followed after injury. Then the rats were under observation for calculation of wound healing time and the rates on post injury day 7, 14, 21, 28. The tissue samples of wound were collected for observation of the histomorphology changes with hematoxylin-eosin staining, for analysis of the expression of calponin and proliferating cell nuclear antigen (PCNA) of fibroblasts by immunohistochemical SP method, and for measure of the apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. Data were processed with analysis of variance and t test. Results The average wound healing time of the experimental group [(25.6±2.8)d] was longer than that of the control group[(19.1±2.1) d], the difference was statistically significant (t=10.49, P<0.05). On post injury day 7, 14, 21, 28, the wound healing rates of the rats in the experimental group [(18.8±4.6)%, (37.6±7.9)%, (66.3±11.4)%, (85.4±4.8)%] were obviously lower than those of the rats in the control group[(40.8±4.5)%, (62.1±6.7)%, (90.2±9.7), (95.4±5.5)%], and the differences were statistically significant(t=9.69, 6.69, 4.51, 3.87; with P values below 0.05). On post injury day 7, 14, 21, the wound lasted and would heal gradually; fibroblasts and nascent capillaries in unhealed wound tissue of rats in the two groups both gradually increased, and more fibroblasts, and nascent capillaries were seen in unhealed wound tissue of rats in the control group. On post injury day 7, 14, 21, 28, the expressions of calponin in the experimental group (1.43±0.07, 1.17±0.11, 0.73± 0.06, 0.77±0.07) were higher than those in the control group (0.75±0.09, 0.60±0.10, 0.63±0.06, 0.64±0.10), and the differences were statistically significant (t=17.58, 10.92, 3.44, 3.10; with P values below 0.05). The expressions of PCNA in fibroblasts of the the experimental group (654.19±102.80, 820.84±112.86, 766.68±156.63, 232.75±55.37)were lower than those of the control group (766.85±73.30, 1322.22±121.44, 1112.35±142.32, 740.79±106.90), and the differences were statistically significant (t=2.52, 8.55, 4.62, 11.94; with P values below 0.05). The expressions of fibroblast apoptosis in the experimental group (58.51±10.89, 41.53±9.95, 27.28±6.58, 20.13±4.23) were higher than those in the control group (30.70±6.41, 25.31±5.74, 17.46±5.36, 15.29±4.10), and the differences were statistically significant(t=6.23, 4.00, 3.27, 2.32; with P values below 0.05). Conclusion The increased expression of calponin during burn wound healing in diabetic rats may regulate the proliferation and (or) apoptosis of fibroblasts in the wound tissue, which is one of the reasons for delayed healing of diabetic wounds. Key words: Diabetes mellitus; Skin; Wound healing; Rats; Fibroblasts; Calponin