Roles of free radicals in reproduction and immune modulations in goats: A review

Abstract

In the body physiology, gonads (i.e. testes and ovaries) and lymphoid organs are most important tissues in terms of metabolism and dynamicity as functional activities of lymphoid organ and gonad are multistep and energy consuming processes they are always performing a number of biochemical reactions. As a causative effect of the same generation of free radicals are quite obvious. Thus, enormous production of free radicals can limit the proper functional management of lymphoid organ and gonad. We noted significantly high levels of SOD, Catalase, GPx activities and ABTS levels in lymphoid organs and gonads of goats during monsoon and significantly low during winter particularly in lymphoid organs. However, all the parameters were significantly high in gonads during winter only. Malonaldihyde; MDA a marker for lipid peroxidation presented a reverse pattern of activity level than SOD being significantly high during summer but the level was significantly low during monsoon and winter. The glucocorticoid receptor expression was significantly high in spleen and thymus of males during monsoon but the level was significantly high only during monsoon in lymphoid organs of males. All the free radical parameters cumulatively suggest that, monsoon and winter are the seasons of stress for both the sexes of goats as suggested by elevated level of glucocorticoid receptor and thus to counteract the elevated stress level melatonin acted as a “coupler” which not only increased the free radical scavenging enzymes but also scavenged free radicals as an amphipatic free molecules particularly during winter. Winter is the most challenging season for female goats due to “cold stress” as well as “gestational stress” along with energy demanding mega two major events i.e. Maintenance of immunity and gestation is occurring simultaneously.