Hidenori Matsushita

Muscle-specific β-enolase concentrations after cross- and random innervation of soleus and extensor digitorum longus in rats

The concentration of beta-enolase, a highly specific marker of the skeletal muscle of rats, was determined in a slow-twitch muscle, the soleus (SOL) and a fast-twitch muscle, the extensor digitorum longus (EDL) after cross-innervation, random reinnervation, or denervation. The beta-enolase concentration is normally high in EDL and low in SOL. When the nerves entering into these muscles were cross-sutured, the beta-enolase concentration in EDL decreased and that in SOL increased to reach an almost equal value in 20 weeks and by the 35th week the SOL ultimately had a higher beta-enolase concentration than the EDL. When the sciatic nerve trunk was completely transected and sutured immediately, the beta-enolase concentration in EDL decreased and that of SOL increased; in 20 weeks SOL had a beta-enolase concentration similar to that of the EDL. When these muscles were denervated by cutting the sciatic nerve trunk, their beta-enolase concentrations were markedly lowered, but EDL still retained on the 12th week a beta-enolase value comparable to the normal SOL. Possible mechanisms behind the observed changes in beta-enolase concentration are discussed.

The Effect of Low-Power Laser Irradiation

We postulated that low-power laser irradiation could produce analgesia, nerv ous activation, and enhancement of wound healing in association with changes in the microcirculation. In order to confirm this hypothesis, we monitored blood flow in rats be fore and after laser treatment. A Ga-Al-As semiconductor laser (wave length: 810nm) was used. Rats were treated at either (1) 300mW×3min, (2) 500mW×3min, (3) 700mW×3min, (4) 300mW×20min, (5) 500mW×20min, or (6) 700mW×20min. Blood flow was monitored in the dorsal skin before and after irradiation using a Laser-Doppler flowmeter. The peripheral circu lation was improved by 20min of irradiation with a 300mW or 500mW semiconductor laser without any irreversible tissue damage, and it was inferred that tissue restoration would result from this change. Different responses were produced depending on the irradiation condi tions, and this suggested that there is a safe range between transition from non effective to effective and from effective to irreversible damage. This range was considered to be the saf est and most effective for low-power laser treatment.