Fig. 4

Hematoxylin–eosin staining and Masson’s trichrome staining of penile specimens. A Representative images of smooth muscle subjected to hematoxylin–eosin staining. Scale bars = 100 μm. B Representative images of smooth muscle stained with Masson’s trichrome staining. The red arrows indicate smooth muscle, and the black arrows indicate collagen fibers. Scale bars = 100 μm. C The ratio of smooth muscle to collagen contents in penile section of T1DM rats. D The ratio of smooth muscle to collagen contents in penile section of T2DM rats. Data are expressed as means ± standard deviation. *P < 0.05 versus the control group; #P < 0.05 versus the DMED group. T1DM type 1 diabetes mellitus, T2DM type 2 diabetes mellitus, Con control, DMED diabetes mellitus erectile dysfunction, CI corpus cavernosum injection, VI tail vein injection