Effect of basic fibroblast growth factor coacervates on experimental neuropathy in diabetic rats / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To explore the therapeutic effect of basic fibroblast growth factor (bFGF) coacervates on diabetic peripheral neuropathy (DPN) in diabetic rats.METHODS Poly (ethylene argininylaspartate diglyceride) (PEAD), heparin and bFGF were dissolved in saline at the mass ratio of 50101 to obtain bFGF coacervates. The loading efficiency of bFGF in the coacervates was analyzed by Western blotting. The release profile of bFGF from the coacevates was detected by ELISA. Male SD rats were ip injected with streptozotocin 65 mg · kg- 1 to establish a diabetic model,and DPN occurred 8 weeks later. The DPN rats were randomly divided into free-coacervate group, bFGF group and bFGFcoacervate group. For bFGF group, bFGF 200 μg·kg-1 was im injected once daily for 3 d. In bFGF-coacervate group, bFGF coacervate solution (244 μL) equal to bFGF 200 μg · k - 1, was im given only once. DPN rats in free- coacervate group were im given the same volume of vehicle(PEAD + heparin) only once. Ten normal age peer rats were taken as normal control group.Footprint analysis was conducted each week to evaluate motor function. On the 30th day after treatment,the rats were sacrificed, and sciatic nerves of both sides were harvested for pathological observation through HE staining. Apoptosis in nerve tissue was detected by DAPI staining, and Ki67 and proliferating cell nuclear antigen (PCNA) protein levels were detected by Western blotting. RESULTS Western blotting and ELISA analysis indicated that bFGF-coacervates were well prepared at a mass ratio of 50101,and controlled bFGF release for at least 35 d. The result of rat behavior evaluation and pathological index test indicated that, compared with normal control group, the sciatic function index (SFI) in free-coacervate group decreased significantly(P<0.01), the internal nerve fibers were accompanied by irregularity and serious demyelination, and there was a large number of apoptotic nuclei and low expressions of Ki67 and PCNA proteins (P<0.01).After injection with bFGF or bFGF-coacervates, the SFI increased progressively (P<0.05, P<0.01), and the proportion of fibers with myelin abnormalities and apoptotic cells was significantly reversed. Moreover, the levels of Ki67 and PCNA was evidently enhanced on the 30th day post- operation (P<0.05, P<0.01). Compared with bFGF group, the results of those detection indicators in bFGF-coacervate group were better (P<0.05, P<0.01). CONCLUSION PEAD and heparin complex can load bFGF with high efficiency, and control its release in a steady manner. For DPN rats,treatment with bFGF-coacervates is more effective than bFGF alone.