In an experimental animal model of a skeletal muscle injury, the administration of an angiotensin receptor blocker significantly improved muscle regeneration and reduced fibrous tissue formation within the injured area

▸ Bedair HS, Karthikeyan T, Quintero A, et al. Angiotensin II receptor blockade administered after injury improves muscle regeneration and decreases fibrosis in normal skeletal muscle. Am J Sports Med 2008;36:1548–54.

Background:

Inhibition of fibrosis and improving regeneration after injury in skeletal muscle may be achieved by transforming growth factor β1 antagonists such as angiotensin receptor blockers

Research question/s:

In an animal model of a laceration injury of the skeletal muscle, does an angiotensin receptor blocker decrease fibrosis and improve muscle regeneration?

Methodology:

Subjects: 40 mice

Experimental procedure: All the animals underwent bilateral gastrocnemius lacerations and were then assigned randomly to three treatment groups: a control group (CON — tap water), a low-dose angiotensin receptor blocker group (losartan, 0.05 mg/ml, dissolved in tap water and administered enterally) (ARBld), or a high-dose angiotensin receptor blocker group (0.5 mg/ml) (ARBhd). Animals were killed 3 or 5 weeks after injury, and the lacerated muscles were examined histologically for muscle regeneration and fibrosis

Measures of outcome: Muscle regeneration (number of regenerating myofibres within a high power field), area of fibrosis (%) at 3 weeks and 5 weeks

Main finding/s:

Conclusion/s:

• In an experimental animal model of a skeletal muscle injury, the administration of an angiotensin receptor …