We overviewed the pathophysiological features of diabetes and its complications in obese
type 2 diabetic rat models: Otsuka Long-Evans Tokushima fatty (OLETF) rat, Wistar fatty
rat, Zucker diabetic fatty (ZDF) rat and Spontaneously diabetic Torii (SDT) fatty rat.
Pancreatic changes with progression of diabetes were classified into early changes, such
as islet hypertrophy and degranulation of β cells, and degenerative changes, such as islet
atrophy and fibrosis of islet with infiltration of inflammatory cells. Renal lesions in
tubuli and glomeruli were observed, and nodular lesions in glomeruli were notable changes
in OLETF and SDT fatty rats. Among retinal changes, folding and thickening were
interesting findings in SDT fatty rats. A decrease of motor nerve conduction velocity with
progression of diabetes was presented in obese diabetic rats. Other diabetic
complications, osteoporosis and sexual dysfunction, were also observed. Observation of
bone metabolic abnormalities, including decrease of osteogenesis and bone mineral density,
and sexual dysfunction, including hypotestosteronemia and erectile dysfunction, in obese
type 2 diabetic rats have been reported.