酸性成纤维细胞生长因子片段脑室内及皮下注射对大鼠夜间摄食的影响

Effect of subcutaneous injection of [Ala]16-aFGF(1-29) on slow transit constipation in mice

AIM: To investigate the potential therapeutical effect of a new acidic fibroblast growth factor (aFGF) fragment - [Ala]¹⁶-aFGF(1-29) against slow transit constipation (STC) in mice and to explore possible mechanisms involved.

METHODS: Sixty ICR mice were divided randomly and equally into test group and control group. A mouse model of STC was established by subcutaneous injection (SC) of morphine [2.5 mg/(kg•d)] for 45 days. The control group was treated with normal saline for the same duration. The fecal character was observed according to the Bristol Stool Form Scale (BSFS), and only mice producing stools conforming to BSFS 1 and 2 were used as STC models. On day 45, six mice were chosen randomly from each group and used to confirm if STC was successfully induced by charcoal propulsion test. The rest mice in each group were divided into test group 1, test group 2, control group 1, and control group 2 (n = 12 each). The test group 1 and control group 1 were treated with [Ala]¹⁶-aFGF(1-29) (300 µg/kg each time, SC) twice per week for 8 weeks, while the test group 2 and control group 2 were treated with the same volume of vehicle. Fecal character was observed in all mice. Eight weeks later, the intestinal propulsion rate (IPR) in mice of each group was measured and the expression of neuron-specific enolase (NSE, a neuronal maker) in the colon was detected by immunohistochemistry and Western blot.

RESULTS: On day 45, the feces in the test group was drier and harder (BSFS 1 and 2) than the control group (BSFS 4 and 5). Both the IPR and expression level of NSE in the test group were significantly lower than those in the control group (63.422% ± 1.791% vs 55.702% ± 1.806%, 1.18800 ± 0.03176 vs 0.88730 ± 0.03554, 0.90520 ± 0.02268 vs 0.71300 ± 0.01654, all P < 0.05 or 0.01). Eight weeks after treatment, the feces in the test group 1 gradually became as smooth and soft (BSFS 4 and 5) as that in the control groups 1 and 2; the IPR and expression level of NSE in colonic tissue in the test group 1 were obviously improved compared to the test group 2 (62.250% ± 5.283% vs 57.190% ± 4.291%, 0.6543 ± 0.0069 vs 0.4193 ± 0.0158, 0.5823 ± 0.019 vs 0.5171 ± 0.0124, all P < 0.05) but showed no significant difference with those in the control groups 1 and 2.

CONCLUSION: Treatment with [Ala]¹⁶-aFGF (1-29) improved constipation symptoms and IPR in STC mice at least partially by protection of the enteric nervous system.