Angiogenic effect of intramuscular administration of basic fibroblast growth factor in atrophied muscles: an experimental study in the rat.

BACKGROUND: Although angiogenic therapy using recombinant growth factors holds much hope for the treatment of ischaemic diseases, there are still many unanswered questions, including its effectiveness on atrophic muscles. OBJECTIVE: To evaluate the angiogenic effects of intramuscularly administered basic fibroblast growth factor (b-FGF) on normal gastrocnemius muscles of rats and atrophic gastrocnemius muscles after tenotomy. METHODS: Forty rats were divided into groups as follows: group A, controls; group B, injected with 1 microg b-FGF; group C, tenotomy performed on the right gastrocnemius muscle; group D, tenotomy and 1 microg b-FGF. Mouse anti-rat CD31 antibody was used to evaluate the number of blood vessels present in histological preparations. RESULTS: There was a significant (p<0.01) decrease in the number of blood vessels compared with the controls in the atrophic muscles of group C. This was similar to the decrease in muscle weight in this group. However, there was a significant (p<0.01) increase in the number of blood vessels compared with the controls in groups B and D. Similarly, there was a significant (p<0.01) increase in the number of blood vessels in group D compared with the atrophic muscles in group C. CONCLUSION: Intramuscular administration of b-FGF increases angiogenesis in both normal and atrophic rat gastrocnemius muscles at the injection area.

Angiogenic effect of intramuscular administration of basic and acidic fibroblast growth factor on skeletal muscles and influence of exercise on muscle angiogenesis.

BACKGROUND: Angiogenic factors which control the angiogenic process represent a promising strategy for restoration of blood flow, but require further evaluation before clinical use. Exercise has also been reported to induce neovascularisation in muscles. OBJECTIVES: To evaluate the angiogenic effects of basic fibroblast growth factor (b-FGF) and acidic fibroblast growth factor (a-FGF) on rat gastrocnemius muscle, when administered intramuscularly, and to compare them with those obtained by daily exercise. METHODS: Forty nine rats were allotted to the following groups: A, controls; B, exercise by swimming; C1 and C2, intramuscular injection of b-FGF and a-FGF respectively; D1 and D2, b-FGF and a-FGF injection in combination with exercise. The antibody mouse anti-rat CD31 was used to evaluate the numbers of blood vessels present in histological preparations of gastrocnemius muscle. RESULTS: Significant increases in the numbers of blood vessels of the right gastrocnemius muscles in groups C1 and D1 were observed compared with controls (p<0.05). There was only a slight increase in angiogenesis in the left gastrocnemius muscle of groups C1 and D1 compared with controls (p>0.05), and there was a decrease in angiogenesis in the gastrocnemius muscle of the swimming group compared with controls. CONCLUSION: The intramuscular administration of b-FGF, but not a-FGF, induced significant local angiogenesis in gastrocnemius muscle at the site of injection.