Do oral amino acid supplements facilitate the healing of rat lung injuries?

OBJECTIVES

Prolonged air leaks following lung injury cause extended hospital stays. This study investigated the effect of nutritional supplements containing arginine, glutamine and β-hydroxy β-methyl butyrate, which were theoretically proven to accelerate wound healing, on air leak and wound healing parameters in a rat lung injury model.

METHODS

Twenty-eight female rats were randomly divided into 4 groups. Experimental groups were given glutamine (Resource Glutamine®) or a mixture of arginine, glutamine and β-hydroxy β-methyl butyrate (Abound®) as a dietary supplement at isonitrogenous and isocaloric doses. On day 3, standard sized lung injuries were created in all rats except the sham group. The rats were sacrificed on day 6, and the lungs were removed for air-leak threshold pressure measurement and histopathological and biochemical analyses.

RESULTS

Loss of body mass was greater in the glutamine group than in the other groups (P = 0.004). Rats that received the amino acid mixture had better results for mature collagen fibre density (P = 0.002) and inflammation suppression (P = 0.003). The sham group had higher values for air-leak threshold pressure and all other histochemical parameters compared to the other groups. Hydroxyproline level did not differ significantly in any of the groups.

CONCLUSIONS

Our results indicated that an oral amino acid mixture was effective in the healing of lung injuries. Isolated glutamine supplementation had an adverse impact on body mass. Randomized clinical studies including larger series are needed. Hydroxyproline does not seem to be a suitable marker for this purpose.

The effect of melatonin on experimentally-induced myringosclerosis in rats

OBJECTIVES

This study determined the preventive effect of melatonin on the occurrence of experimentally-induced myringosclerosis of the tympanic membrane (TM).

MATERIALS AND METHODS

Twenty Wistar albino-type rats weighing approximately 300 g each were randomly separated into two groups and myringotomized on the left TMs: group 1 rats (n=6) received intraperitoneal melatonin injections 10 mg/kg/day whereas group 2 rats (n=12) were treated with physiological serum only. The remaining two rats were served as the control group for histological comparison and standardization. After 15 days of treatment, myringotomized membranes were examined by otomicroscopy and harvested for histopathological evaluation. The functional effect of myringosclerotic plaques in the TMs of the two groups were compared with tympanometric measurements.

RESULTS

Tympanic membranes in group 2 revealed extensive myringosclerotic plaques, on the other hand, TMs in group 1 showed faint or no existence of myringosclerosis. The mean magnitude of the maximum admittance from group 2 measured by tympanometry reduced to about 40% of the values obtained from group 1 (Z=-2,067, p=0.041). The mean magnitude of the maximum admittance from melatonin group was very close to the mean tympanometric value of non-myringotomized Wistar albino rats, demonstrating a functional outcome.

CONCLUSION

The occurrence of myringosclerosis following experimental myringotomy can be hindered by systemic melatonin treatment.

Comparison of efficacy of ivermectin and doramectin against mange mite (Sarcoptes scabiei) in naturally infested rabbits in Turkey

The authors used 14 New Zealand rabbits (5 naturally infested rabbits and 9 in-contact rabbits) for Sarcoptes scabiei treatment in this study. Signs, such as itchy ears, eyes, tail and abdominal skin, alopecia and pyoderma, were considered to be the cause of these disorders. Infested rabbits were grouped according to the intensity of S. scabiei infestation (low, medium and high). Each group was then divided into two subgroups; in one subgroup the rabbits received ivermectin (1%) and, in the other, doramectin (1%). All subgroups received a subcutaneous injection at a dosage of 400 microg/kg body weight every 80 h on three occasions. On day 28 after commencing the treatment, all the rabbits in the first two groups had recovered completely. Although both drugs were applied at the same time and at the same dose, the third group (high degree of infestation), revealed, both microscopically and macroscopically, that ivermectin has more rapid effect than doramectin. Treatment was effective in all groups.