The Nikkei stock index on Friday extended its losing streak to eight days for the first time since October 2021, as gains after a plunge were erased amid uncertainty over whether the Bank of Japan will raise interest rates next week. The 225-issue Nikkei Stock Average ended down 202.10 points, or 0.53 percent, from Thursday at 37,667.41, its lowest closing since April 25. The broader Topix index finished 10.32 points, or 0.38 percent, lower at 2,699.54. On the top-tier Prime Market, top decliners were transportation equipment, electric power and gas, and insurance issues. The U.S. dollar edged…