Effects of Local Testicular Heating on Bcl-2 and Bax Protein Expression in Spermatogenic Cells in Rats

Objective To investigate the expression of Bcl-2 and Bax in spermatogenic cells induced by local testicular heating in rats Methods Forty adult male SD rats were divided into experimental group and control group at random. According to day 0.5, 1, 3 and 6 after local testicular heating, each group was divided into 4 subgroups： experimental subgroup （n=6） and control subgroup （n=4）. The expression of Bcl-2 and Bax in the spermatogenic cells was detected on day 0.5, 1, 3 and 6 after heat exposure by using immunohistochemistry. Results Compared with control groups, the ratio of positive cells and content of Bcl-2 positive cells significantly decreased in all experimental subgroups （P〈0.01）. The content of Bax positive cells increased in all experimental subgroups （P〈0.01）, the ratio of positive cells which had no significant difference （P〉0.05） except 6 d group decreased （P〈0.01 ）. Redistribution of Bax from a cytoplasmic to perinuclear or nuclear localization could be observed after heating. Conclusions Expression of Bcl-2 would decrease and Bax would increase with redistribution in spermatogenic cells in rats after heating. The change of Bcl-2 and Bax expression in spermatogenic cells would be correlated with the spermatogenic cell apoptosis induced by heating.

Analysis of DNA Content of Various Types of Spermatogenic Cells in Rat after Testicular Heating with Flow Cytometry

To measure DNA contents of spermatogenic cells and analyze the efficiency of spermatogenesis after testicular heating in rat Methods Eighty adult male Sprague-Dawley rats were randomly divided into experimental group （43 ℃, 30 min） and control group （22 ℃, 30 min）. According to day 0.5, 1, 3, 6, 10, 25, 35 and 50 after local testicular heating, every group was divided into 8 subgroups： experimental subgroups （n=6） and control subgroups （n=4）. DNA contents of various types of germ cells were observed with flow cytometry （FCM） in all groups. Results Compared with control groups, percentages of 4C cell （primary spermatocyte） in 0.5-35 d groups and percentages of 1C cell （spermatid and sperm） in 6-50 d groups significantly decreased in experimental groups （P〈0.05）, and percentages of 2C cell （spermatogonium and second spermatocyte） in 3 -35 d experimental groups increased significantly after heating （P〈0.05）. 4C：2C in all of 8 experimental groups and 1C：2C in 3-35 d experimental groups were down （P〈0. 05）, and in 1 d experimental group 1C：4C was up after heating （P〈0.05）. Conclusions After being heated, the number of spermatocyte firstly decreased, and then that of spermatid and sperm decreased too. Heat influences several stages in spermatogenesis and results in suppression of spermatogenesis. Flow cytometry is an effective method for researching on the change of spermatogenesis and has significance on mechanism about changing of spermatogenic cells induced by heat.

Use of Random Amplified Polymorphic DNA Analysis for Economically Important Food Crops

The objective of this review is to summarize numerous studies on the use of the random amplified polymorphic DNA （RAPD） technique on rice, corn, wheat, sorghum, barley, rye, and oats to examine its feasibility and validity for assessment of genetic variation, population genetics, mapping, linkage and marker assisted selection, phylogenetic analysis, and the detection of somaclonal variation. Also we discuss the advantages and limitations of RAPD. Molecular markers have entered the scene of genetic improvement in different fields of agricultural research. The simplicity of the RAPD technique made it ideal for genetic mapping, plant and animal breeding programs, and DNA fingerprinting, with particular utility in the field of population genetics.