The Study On The Effects Of Aging And Growth Hormone On Erectile Function Of Aged Rat

The study consists of two parts: (1) To investigate the alteration of erectile function and nNOS-containing nerve fibers in aged rats; (2)To investigate the effects of growth hormone(GH) on the erectile function and the number of nNOS-containing nerve fibers in penis of aging rats.Part oneObjective: To investigate the alteration of erectile function and nNOS-containing nerve fibers in aged rats. Methods: Sixteen male SD rats were grouped by age into young group(8 3-month-old rats) and aged group(8 18-month-old rats). The two groups of rats were tested for erectile function after APO injection and then sacrificed for the detection of nNOS-containing nerve fibers in the corpus cavernosum by S-P method. Results: Compared with young group, the erectile frequency and rate decreased significantly in aged group(P<0.05); the number of nNOS-containing nerve fibers in aged group was lower than in young group (P<0.01). Conclusions: The erectile function in aged rats decreased significantly, which may be related with the decrease of nNOS-containing nerve fibers in the corpus cavernosum.Part twoObjectives: To investigate the effects of growth hormone(GH) on the erectile function and the number of nNOS-containing nerve fibers in penis of aging rats. Methods: Twenty-four aging male SD rats(18 months) were divided into two groups randomly :GH intervention group and control group. After four weeks and eight weeks, one second rats of each group were selected respectively and tested for erectile function after APO injection and then sacrificed for the detection of nNOS-containing nerve fibers in the penis by streptavidin-peroxidase conjugated method(S-P method). Results: After four weeks, the erectile function and the number of nNOS-containing nerve fibers had no significant difference(P>0.05) between GH intervention group and control group. After eight weeks, the erectile frequency had significant difference(P<0.05) between the two groups, while the erectile rate had no difference; the number of nNOS-containing nerve fibers in GH intervention group was higher than that in control group, and there was significant difference(P<0.01). Conclusions: Growth hormone enhances regeneration of nNOS-containing nerve fibers in aging rat penis and improves erectile function to some extent.