Effects Of Cold Stimulation And High-fat Diet On Sperm Function In Rats And Its Reproductive Biology

Objective:?1?To explore the effects of cold stimulation,high-fat diet?HFD?,and cold stimulation combined with HFD on sperm function in rats.Based on evaluation of sperm function,a asthenospermia model was established to explore its feasibility;?2?By researching the changes of HPG axis,HPA axis,HPT axis morphology and related hormones in asthenozoospermia rats,the neuroendocrine-mechanism of sperm function in rats with asthenozoospermia model was initially revealed.Methods:?1?66 SPF grade male SD rats were randomly divided into normal control group?group N,n=12?,Fed with standard feed at normal environment?22±2??;The rats in the cold stimulation group?group C,n=18?were fed with standard feed in cold environment?4±0.5?,10:00-18:00/d?.The rats in the HFD group?group H,n=18?were fed with HFD at normal environment?22±2??.The rats in cold stimulation combined HFD group?group CH,n=18?were fed with high fat diet and in cold environment?4±0.5?,10:00-18:00/d?.The growth and development of rats were detected during the modeling.After 23weeks,through the detection and evaluation of sperm function of rats in each group,the rats with asthenospermia in group C,H and CH were selected,and the group CA,HA and CHA were established.Combined with the testis and epididymal coefficients of each group of rats,a systemic evaluation was performed on the spermatozoa model rats.?2?The levels of peripheral serum lipids and liver function of rats in each group were measured by automatic biochemical detector.?3?The levels of peripheral serum gonadal axis related hormones?T,E₂,LH,FSH,PRL?and thyroid axis related hormones?T3,T4,FT3,FT4,TSH?were detected by radioimmunoassay,the adrenal axis related hormones?EPI,CORT,NA?were measured by ELISA method.The hypothalamus,pituitary,adrenal gland and thyroid were stained with HE,and the morphological changes were observed by optical microscope.Results:?1?The results of growth characteristics of rats in each group during the modeling period:the average body weight,weight gain and food intake of each period in group C and CH were not significantly different from group N,but the average values were lower than group N.The body weight of group H was significantly higher than group N from the 16th week to the end of modeling,and the weight gain of each group was mainly concentrated in the 1-8th weeks.?2?The results of sperm function test:PR sperm and PR+NP sperm in group C,H and CH were significantly lower than those in group N,but there was no significant difference in sperm concentration.The modeling rates of asthenospermia rats in group C,H and CH were50%,61.11%and 61.11%,respectively.Compared with group N,the PR sperm of group C,H and CH decreased by 82.97%,59.55%and 56.60%,respectively.And the sperm motility decreased by 57.12%,37.98%and 41.58%,respectively.There was no significant difference in sperm concentration?P>0.05?.?3?The organ coefficient of testis and epididymis in asthenospermia rats:compared with group N,the organ coefficient of testis and epididymis in group CA and HA decreased significantly?P>0.05?.?4?Blood lipids and liver function:compared with group N,TC in group CA,CHA,and LDL in group HA,CHA increased significantly.There were significant differences in HDL and LDL in group HA.Compared with group N,ALT increased significantly in group CA,but decreased significantly in group HA,and TP increased significantly in group CHA.?5?The results of HPG axis-related hormone levels:compared with group N,the level of E₂in group CA and HA was significantly increased and LH was significantly decreased?P<0.05?.T and E₂ were mainly increased in group CHA;Results of adrenal axis-related hormone levels:Compared with groupN,the level of EPI in group CA and CHA was significantly increased,and the level of NA in group HA and CHA was significantly increased in group N;Results of thyroid axis-related hormone levels:compared with group N,there was no significant change in HPT axis related hormones in group CA,but the level of T3/T4 increased significantly.The levels of T3 and T4 in group HA were significantly higher than those in group N?P<0.05?.Although TSH decreased,it was not significant?P>0.05?.The levels of T3 and T3/T4 in group CHA were significantly increased in group N?P<0.05?.?6?Histological changes of HPG axis,HPA axis and HPT axis by optical-microscope:the histological of hypothalamus,pituitary,testis,epididymis,adrenal gland and thyroid were normal in group N.Compared with group N,there were proliferation and disorder of hypothalamic paraventricular nucleus neurons in group CA,HA and CHA;The arrangement of pituitary cells was disordered in group CA,HA and CHA,chromophobe cells increased and tissue edema in group CA and CHA,and vacuolar changes were more common in group HA;Spermatozoa were also found in testicular seminiferous tubules in group CA,HA and CHA,but not as full as group N.At the same time,interstitial hyperemia and edema were more obvious in group CA,the number of Sertoli cells decreased obviously in group HA and CHA;In group CA,the epididymal epithelial cells decreased,uneven and the stroma was loose.In group HA,the epididymal epithelial cells proliferated and thickened,uneven and the stroma was more loose.The structural changes of adrenal gland in group CA were mainly disorder of cell arrangement and edema.Vacuole-like changes in fascicular zone of adrenal cortex were common in group HA and CHA,especially in group HA.The thyroid follicles in group CA and HA showed emptying,less colloid,and follicular epithelial hyperplasia was more serious in group CA and HA.Thyroid epithelial hyperplasia and destruction of follicular structure were also found in group CHA,but there were still many glial-rich follicles.Conclusions:?1?.Cold stimulation and HFD can affect sperm function by significantly reducing sperm motility and viability,and can successfully establish the rat model of asthenospermia.?2?Lipid metabolism disorder and liver function abnormality occurred in asthenospermia rats induced by HFD and cold stimulation combined with HFD.?3?The significantly increased level of E₂ had a great effect on the decrease of sperm motility.?4?The rats with asthenospermia induced by cold stimulation mainly had chronic stress response,and LDL increased significantly.Lipid metabolism disorder and hyperlipidemia in asthenospermia rats induced by HFD.Lipid metabolism disorder and chronic stress response occurred in asthenospermia rats induced by cold stimulation combined with HFD.