ABSTRACT
Chitosan nanoparticles conjugated with 17α-methyltestosterone (CSâ¯+â¯MT) were used for studying their effect on the testicular development of Clarias batrachus during different reproductive phases. The size of chitosan nanoparticles was 127.2â¯nm and the nano-conjugated 17α methyltestosterone (17α-MT) was 196.1â¯nm (20â¯mg/100â¯ml of chitosan). Single injections of CSâ¯+â¯MT at different doses such as 0.01, 0.1 and 0.5⯵g/g body weight were administered to adults during the pre-spawning, spawning and post-spawning phase. Nano-conjugated steroid was effective at the lower dose; showing an increase in the Gonadosomatic Index (GSI) and 11-ketotestosterone level compared to the control group. Histological observations confirmed the dose-dependent advancement in spermatogenesis. These findings indicate the possibility of using CSâ¯+â¯MT for enhancing gonadal maturity of C. batrachus.
Subject(s)
Catfishes , Chitosan/pharmacology , Methyltestosterone/pharmacology , Testis/drug effects , Testis/growth & development , Animals , Aquaculture/methods , Catfishes/growth & development , Chitosan/chemistry , Male , Methyltestosterone/chemistry , Sex Differentiation/drug effects , Sexual Maturation/drug effects , Spermatogenesis/drug effectsABSTRACT
Steroidogenic acute regulatory protein (StAR) is responsible for the relocation of cholesterol across mitochondrial membrane in vertebrates and is, therefore, a key factor in regulating the rate and timing of steroidogenesis. In the present study, we developed chitosan nanoparticle (CNP) conjugated StAR gene construct (CNP-pcDNA4-StAR) in a eukaryotic expression vector, pcDNA4/HisMax A. CNPs of 135.4nm diameter, 26.7mV zeta potential and 0.381 polydispersity index were used for conjugation. The loading efficiency (LE) of pcDNA4-StAR construct with CNPs was found to be 86%. After the 24h of intramuscular injection, the CNP-pcDNA4-StAR plasmid could be detected from testis, brain, kidney and muscle tissues of Clarias batrachus. The transcript levels of important reproductive genes viz. cyp11a1, cyp17a1, 3ß-hsd, 17ß-hsd and cyp19a1 in CNP-pcDNA4-StAR treated group were initially low up to 24h, but significantly increased subsequently up to 120h. In naked pcDNA4-StAR treated group, the mRNA level of 3ß-hsd, 17ß-hsd and cyp19a1 increased initially up to 24h, while cyp11a1 and cyp17a1 increased up to 48h and then started declining. Similar results were obtained for 11-Ketotestosterone and 17ß-estradiol. The results indicate relatively long lasting effects of nano-conjugated construct compared to the construct alone. Furthermore, the histopathology of gonads and liver authenticates its possible role in the gonadal development in fish without any adverse effect.