MR 31. Impairment on the Morphology of Leydig Cells and Testosterone Synthesis Function in Rats By ⁶⁰Co-γ

Objective: To investigate the acute damage degree on the morphology of Leydig cells and testosterone synthesis function different doses of ⁶⁰Co-γin rats by.

Methods: Sixty male SD rats were equally randomized into five groups: Group A: also the normal control group, with ⁶⁰Co-γ exposure adopted only over testis; Group B: 4+4 Gy; group C: 6+6 Gy; group D: doses was 2+10 Gy; and group E: 6+8 Gy.The exposure duration was 24 h. Serum luteinizing hormone (LH) and testosterone (T) levels were determined by enzyme-linked immunoassay 48h after of the exposure. The histology of the testis tissues was observed under microscope. The mRNA levels in the steroidogenic acute regulatory protein (StAR) and in the cytochrome P450 side chain cleavage (P450scc) from the Leydig cells were determined by RT-PCR.

Results: Compared with the normal control (group A), the levels of serum LH in the groups of ⁶⁰Co-γ exposure (groups B, C, D, and E) were significantly higher (P<0.05), and the levels of serum T were significantly lower than normal (P<0.05). Under the microscope, the Leydig cells were smaller and less than normal, cytoplasms were less, cell nucleuses were shrunken, and chromatins were enriched and anachromasis. The expressions of mRNA in StAR and P450scc were also significantly lower than the control group (P<0.05).

Conclusions: The impairment on the morphology of Leydig cells and testosterone synthesis function is obviously after ⁶⁰Co- γ exposure. The damage degree is associated with both the total doses and the biggest exposure doses.