effect of omega-3 on renal functions and structure in experimental hyperthyroidism: possible role of angiotensin-converting enzyme 1

Hyperthyroidism is associate with reduced serum creatinine and urea, renal hypertrophy and eventually chronic renal disease. The aim of the present study was to investigate the potential therapeutic value of omega-3 on renal functions and structural changes induced by hyperthyroidism and the effect of omega-3 on angiotensin-converting enzyme 1 [ACE1] as a possible mechanism. Thirty rats were randomly divided into three groups. Control group received the vehicle. Hyperthyroid group was treated with L-thyroxine 0.1 mg/kg/day for 6 weeks and hyperthyroid-omega-3 treated group received L-thyroxine 0.1 mg/kg/day alone for 2 weeks followed by concurrent treatment with L-thyroxine 0.1 mg/kg/day and 3 g/kg/day omega-3 orally for 4 weeks. Serum creatinine, blood urea nitrogen [BUN], serum total antioxidant capacity [TAC], renal ACE1 and kidney weight to body weight [KW/BW] ratio were determined. Histopathological studies using H and E, Masson trichrome were done. Administration of L-thyroxine induced a significant decrease in serum creatinine, BUN and TAC and a significant increase in renal ACE1 and KW/BW ratio. Moreover, renal cortex thickness was increased, glomerular capillaries were congested with an increase in mesangial matrix. Proximal convoluted tubules [PCTs] were degenerated with no structural changes were observed in distal convoluted tubules [DCTs], afferent and efferent arterioles. Omega-3 administration is nearly normalized serum creatinine, BUN, TAC and renal ACE1 levels and ameliorates L-thyroxine-induced renal hypertrophy, glomerular congestion and PCTs degenerative changes. In conclusion, omega-3 administration has protective effects against hyperthyroidism-induced functional and structural changes. These reno-protective effects are possibly mediated by reducing ACE1 activity and its antioxidant activity

Gender differences in the electrophysiological properties of rabbit a trio ventricular node

There are gender differences in the electrocardiographic parameters and in the prevalence of arrhythmias. Women have faster heart rale, longer QT interval, shorter PR interval and shorter atrioventricular node [AVN] effective refractory period as compared to men. These changes may be due to gender differences in ion channel expression and thereby in currents responsible for the electrophysiological function of the AVN, Gender differences in the electrophysiological function in the AVN have been investigated using extracellular potential recording from isolated spontaneously beating A VN preparations from adult male and female New Zealand White rabbits under control conditions and after the application of ion channel b lockers. Cycle length of isolated A VN preparations was significantly longer in adult female as compared to adult male. 2 mMCs, an Ifblocker, significantly increased the cycle length of adult male [i.e. slowed the spontaneous activity of the AVN; by 120%] and tended to increase the cycle length in adult female by 28%. Hundred nM TTX, a b locker of TTX sensitive neuronal l[na] tended to increase the cycle length of both adult male and female. In conclusion, If and TTX-sensitive currents may be partly responsible for the difference in AVN cycle length and thereby in the AVN rate/ pacemaking between adult male and female