He-Ne Laser  Irradiation  Alters Bothrops jararacussu  Venom Effects In Skeletal Muscle

RD. Almeida-Silva¹; GB Leite¹; L Rodrigues-Simioni¹; MA Cruz-Höfling².

1 Department of Pharmacology, 2 Department of Histology and Embryology,  UNICAMP, Campinas, SP, Brazil.

Antivenom therapy is ineffective in neutralizing the severe local tissue damage following a snakebite envenoming. The need for an effective first-aid regimen aimed at minimizing these effects is of uttermost importance. Here we describe some effects of HeNe laser irradiation on muscle injected with B. jararacussu crude venom. The tibialisanterior muscle of adult anesthetized Wistar rats were injected in its medium third either with venom (60 g/0.02 ml) or saline (control). Three He-Ne laser incident energy densities (l = 632.8 nm, 3 mW) were administered after 60 min of venom: 3.5 J/cm² (single exposure); 3.5 J/cm² (three exposures at interval of 20 min each) and 10.5 J/cm². A myographic record, serum CK levels, histopathological  and morphometrical analysis was done and compared to unirradiated muscles. The energy density of 3.5 J/cm² (single or three exposures) induced a significant decrease of 64% and 40.5%, respectively, of the injured area (15.9 ± 1.5% and 26.3 ± 4.5%, respectively, against 44.2 ± 5.7% in unirradiated ones) and a significant (62%) decrease of the neuromuscular blockade (3.5 J/cm², single dose) compared to the unirradiated group. Serum CK levels ranged from 455 ± 4.5% in unirradiated envenomed rats to 190.3 ± 23.4% in irradiated rats (3.5 J/cm², single exposure) (p<0.05). We suggest  that HeNe laser irradiation at appropriate dosage, reduces myonecrosis caused by B. jararacussu venom and improves muscle performance.

Support: CAPES, CNPq, FAEP, FAPESP.

Correspondence to: rosanydoin@hotmail.com