Mitochondrial electron transport chain complexes in aging rat brain and lymphocytes

Several lines of evidence suggest thatmitochondria not only plays a key role in thecausation of aging, but it is also the mostadversely affected organelle during aging. Theaim of the present study was to examine therole of mitochondria in the aging process bydetermining whether the activities of various`electron transport chain' (ETC) complexes aredeleteriously affected during aging in the ratbrain and lymphocytes. The enzyme activity ofETC complexes I–V, and citrate synthase (CS)were assayed from discrete brain areas viz.,cerebral hemisphere (CH), cerebellum (CB),brain stem (BS) and diencephalon (DC), along withthe lymphocytes from four different age groups ofrats, namely, 1-month-old rats, 3–4-month-oldadults, 12-month-old adults and24-month-old aged rats. Significant decline wasobserved in all the enzyme activities in 12 and24-month-old rats as compared to 3–4-month-oldadult rats. Moreover, one-month-old ratsshowed lower levels of ETC complexes ascompared to three to four-month-old rats. Lymphocytes anddiscrete brain areas showed a parallel patternof age-related alterations in the mitochondrialETC complexes and CS. The analysis of suchalterations is important in determining theultimate basis of neuronal dysfunctionassociated with aging, and defining thenature of these changes may also help to developtherapeutic means to cure not only the elderly butalso individuals suffering from certain organicor psychiatric disorders.