Effect of IR Laser Radiation on Germ Cell DNA Content after One Cycle of the Seminiferous Epithelium

Abstract

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.

Quantitative and qualitative changes of the seminiferous epithelium induced by Ga. Al. As. (830 nm) laser radiation

“…This implies that laser irradiation can result in modifications in cell cycle phases and acceleration of spermiogenesis, which is in agreement with results obtained by Bermudez et al [3,4] and Porras et al [26], suggesting that IR laser light probably modifies the phase lengths of the spermatogonia cell cycle and accelerates the mitotic rhythm.…”

“…laser radiation on the seminiferous epithelium were found to depend on the doses applied. This point has been reported previously by Bermudez et al [4] who showed an increase in the germ cell DNA content after IR laser radiation, depending on the applied doses and the stage of germ cell differentiation. Karu [32,33] reported a biostimulatory effect for low doses of laser light and contend that the photocontrol of the cell metabolism from the viewpoint of positive effect takes place only in a narrow dose range of light; the increase in dose is accompanied by growth inhibition and cell lethality.…”

“…Bermudez et al [3,4], working on the germ cell DNA content, suggested the existence of greater number of abnormal gametes after IR laser irradiation, which would imply a higher degree of cell degeneration. So, chromosomal abnormality induced by 46.80 J/cm 2 laser irradiation may be one of the reasons involved in the increased germ cell degeneration and structural abnormality of spermatids found in these testes agrees with results obtained by Bermudez et al [3,4] and Porras et al [26]. Moreover, considering the changes occurred in mitochondria and abnormalities revealed in the tail region of elongating spermatids, it is suggested that high doses of laser light can led to immotile sperm production by seminiferous epithelium.…”

“…Evidences show that low-intensity laser light stimulates both nucleic acid synthesis and cellular proliferation in E. coli, Hela tumor cells, fibroblasts, lymphocyte, and thyroid cells other than germ cells. These stimulatory effects reach their maximum level in a few hours or days after irradiation [4].…”

“…Porras et al [26], working with testicular cells, showed an increase in the number of spermatogonia and Celani et al [27][28][29] reported a significant increase of testosterone production by mouse interstitial cells after laser irradiation. Bermudez et al [3,4] reported an increase in the germ cell DNA content shortly after IR laser radiation and after one cycle of the seminiferous epithelium. They studied two different levels of radiation: one according to clinical application (28.05 J/cm 2 ) and another known to increase the germ cell number (46.80 J/cm 2 ).…”