Quantitative study of the morphological changes in the thyroid gland following IR laser radiation

Effect of IR laser radiation on germ cell DNA content after one cycle of the seminiferous epithelium

The effect of IR laser radiation on rat germ cells was investigated by cytophotometric quantification of the nuclear DNA content after a 15-day resting period. Two different doses of radiation energy were applied: 28.05 J/cm2 and 46.80 J/cm2. Both doses were found to increase the percentages of both spermatogonia with a 4c DNA content and primary spermatocytes with a > 4c DNA content. The elongating and elongated spermatids had a c DNA nuclear content, except for a small proportion (5%) of elongating cells that displayed a 2c DNA content at 28.05 J/cm2. Results revealed an increase in the germ cell DNA content after one cycle of the seminiferous epithelium after in vivo exposure to IR laser light. The laser sensitivity of the germ cells appeared to be related to their stage of differentiation and to the radiation energy applied, and the spermatogonia were the most sensitive. In all cases the lowest dosage induced the highest alteration.