$connection = new \PDO("mysql:host=$host;dbname=$db;charset=$charset", $db_user, $db_pass, array(
    \PDO::ATTR_ERRMODE            => \PDO::ERRMODE_EXCEPTION,
    \PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC
));
$statement = $connection->query("SELECT * articles ORDER BY id DESC LIMIT 10");
while ($row = $statement->fetch()) {
   echo mb_substr($row['content'], 0, 300, mb_detect_encoding($row['content']));
}